diff --git a/datasette/app.py b/datasette/app.py index 42be7425..7499c6f9 100644 --- a/datasette/app.py +++ b/datasette/app.py @@ -49,6 +49,8 @@ from .events import Event from .plugins import DEFAULT_PLUGINS, get_plugins, pm from .renderer import json_renderer from .resources import DatabaseResource, TableResource +from .telemetry import tracer +from .telemetry_registry import STARTUP from .tokens import TokenInvalid from .tracer import AsgiTracer from .url_builder import Urls @@ -778,57 +780,69 @@ class Datasette: # This must be called for Datasette to be in a usable state if self._startup_invoked: return - # Register event classes - event_classes = [] - for hook in pm.hook.register_events(datasette=self): - extra_classes = await await_me_maybe(hook) - if extra_classes: - event_classes.extend(extra_classes) - self.event_classes = tuple(event_classes) + # invoke_startup() runs before any request exists, so every span its + # children create - the register_* hook dispatches, the internal + # catalog's db.query/db.write spans, and the prepare_connection + # warm-up of the read connections those touch - would otherwise be + # its own orphan root trace: around twenty of them on a fresh + # instance. Bracketing the whole thing gives them somewhere to belong. + # A connection warmed lazily later, by a request touching a new + # database for the first time, nests under that request instead: + # this span has already ended by then. + with tracer.start_as_current_span(STARTUP): + # Register event classes + event_classes = [] + for hook in pm.hook.register_events(datasette=self): + extra_classes = await await_me_maybe(hook) + if extra_classes: + event_classes.extend(extra_classes) + self.event_classes = tuple(event_classes) - # Register actions, but watch out for duplicate name/abbr - action_names = {} - action_abbrs = {} - for hook in pm.hook.register_actions(datasette=self): - if hook: - for action in hook: - if ( - action.name in action_names - and action != action_names[action.name] - ): - raise StartupError(f"Duplicate action name: {action.name}") - if ( - action.abbr - and action.abbr in action_abbrs - and action != action_abbrs[action.abbr] - ): - raise StartupError(f"Duplicate action abbr: {action.abbr}") - action_names[action.name] = action - if action.abbr: - action_abbrs[action.abbr] = action - self.actions[action.name] = action + # Register actions, but watch out for duplicate name/abbr + action_names = {} + action_abbrs = {} + for hook in pm.hook.register_actions(datasette=self): + if hook: + for action in hook: + if ( + action.name in action_names + and action != action_names[action.name] + ): + raise StartupError(f"Duplicate action name: {action.name}") + if ( + action.abbr + and action.abbr in action_abbrs + and action != action_abbrs[action.abbr] + ): + raise StartupError(f"Duplicate action abbr: {action.abbr}") + action_names[action.name] = action + if action.abbr: + action_abbrs[action.abbr] = action + self.actions[action.name] = action - # Register column types (classes, not instances) - self._column_types = {} - for hook in pm.hook.register_column_types(datasette=self): - if hook: - for ct_cls in hook: - if ct_cls.name in self._column_types: - raise StartupError(f"Duplicate column type name: {ct_cls.name}") - self._column_types[ct_cls.name] = ct_cls + # Register column types (classes, not instances) + self._column_types = {} + for hook in pm.hook.register_column_types(datasette=self): + if hook: + for ct_cls in hook: + if ct_cls.name in self._column_types: + raise StartupError( + f"Duplicate column type name: {ct_cls.name}" + ) + self._column_types[ct_cls.name] = ct_cls - for hook in pm.hook.prepare_jinja2_environment( - env=self._jinja_env, datasette=self - ): - await await_me_maybe(hook) - # Ensure internal tables and metadata are populated before startup hooks - await self._refresh_schemas() - await self._save_queries_from_config() - # Load column_types from config into internal DB - await self._apply_column_types_config() - for hook in pm.hook.startup(datasette=self): - await await_me_maybe(hook) - self._startup_invoked = True + for hook in pm.hook.prepare_jinja2_environment( + env=self._jinja_env, datasette=self + ): + await await_me_maybe(hook) + # Ensure internal tables and metadata are populated before startup hooks + await self._refresh_schemas() + await self._save_queries_from_config() + # Load column_types from config into internal DB + await self._apply_column_types_config() + for hook in pm.hook.startup(datasette=self): + await await_me_maybe(hook) + self._startup_invoked = True def sign(self, value, namespace="default"): return URLSafeSerializer(self._secret, namespace).dumps(value) diff --git a/datasette/database.py b/datasette/database.py index e162d34e..7114a691 100644 --- a/datasette/database.py +++ b/datasette/database.py @@ -1,18 +1,45 @@ import asyncio import atexit +import contextvars import inspect import os import queue import sys import tempfile import threading +import time import uuid from collections import namedtuple from pathlib import Path import sqlite_utils +from opentelemetry import context as otel_context_api +from opentelemetry.trace import Link, Status, StatusCode, get_current_span from .inspect import inspect_hash +from .telemetry import sql_attribute, sql_operation_name, tracer +from .telemetry_registry import ( + DB_COLLECTION_NAME, + DB_NAMESPACE, + DB_OPERATION_NAME, + DB_QUERY, + DB_QUERY_EXECUTE, + DB_QUERY_TEXT, + DB_SYSTEM, + DB_WRITE_EXECUTE, + DB_WRITE_QUEUE_WAIT, + EXECUTEMANY, + EXECUTESCRIPT, + INTERRUPTED, + ISOLATED_CONNECTION, + PARAM_COUNT, + PARAM_SETS, + ROWS_RETURNED, + SQL_ERROR_SUPPRESSED, + TIME_LIMIT_MS, + TRANSACTION, + TRUNCATED, +) from .tracer import trace from .utils import ( call_with_supported_arguments, @@ -257,10 +284,24 @@ class Database: cursor, return_all=return_all, returning_limit=returning_limit ) - with trace("sql", database=self.name, sql=sql.strip(), params=params): - results = await self.execute_write_fn( - _inner, block=block, request=request, transaction=transaction - ) + # SIM117 wants these two context managers merged. They are kept nested + # deliberately: the hand-rolled tracer's wrapper is on its way out, and + # nesting makes removing it a single-line deletion. + with trace( # noqa: SIM117 + "sql", database=self.name, sql=sql.strip(), params=params + ): + with tracer.start_as_current_span(DB_QUERY, kind=DB_QUERY.kind) as span: + span.set_attribute(DB_SYSTEM, "sqlite") + span.set_attribute(DB_NAMESPACE, self.name) + span.set_attribute(DB_QUERY_TEXT, sql_attribute(sql)) + operation_name = sql_operation_name(sql) + if operation_name: + span.set_attribute(DB_OPERATION_NAME, operation_name) + if params: + span.set_attribute(PARAM_COUNT, len(params)) + results = await self.execute_write_fn( + _inner, block=block, request=request, transaction=transaction + ) return results async def execute_write_script(self, sql, block=True, request=None): @@ -269,10 +310,22 @@ class Database: def _inner(conn): return conn.executescript(sql) - with trace("sql", database=self.name, sql=sql.strip(), executescript=True): - results = await self.execute_write_fn( - _inner, block=block, transaction=False, request=request - ) + # Nested on purpose - see the note in execute_write(). + with trace( # noqa: SIM117 + "sql", database=self.name, sql=sql.strip(), executescript=True + ): + # No db.operation.name here, deliberately: executescript() runs + # several semicolon-separated statements, and semantic conventions + # say the attribute should not be extracted from query text that + # can hold more than one operation - see sql_operation_name(). + with tracer.start_as_current_span(DB_QUERY, kind=DB_QUERY.kind) as span: + span.set_attribute(DB_SYSTEM, "sqlite") + span.set_attribute(DB_NAMESPACE, self.name) + span.set_attribute(DB_QUERY_TEXT, sql_attribute(sql)) + span.set_attribute(EXECUTESCRIPT, True) + results = await self.execute_write_fn( + _inner, block=block, transaction=False, request=request + ) return results async def execute_write_many(self, sql, params_seq, block=True, request=None): @@ -289,12 +342,26 @@ class Database: return conn.executemany(sql, count_params(params_seq)), count + # Nested on purpose - see the note in execute_write(). with trace( "sql", database=self.name, sql=sql.strip(), executemany=True ) as kwargs: - results, count = await self.execute_write_fn( - _inner, block=block, request=request - ) + with tracer.start_as_current_span(DB_QUERY, kind=DB_QUERY.kind) as span: + span.set_attribute(DB_SYSTEM, "sqlite") + span.set_attribute(DB_NAMESPACE, self.name) + span.set_attribute(DB_QUERY_TEXT, sql_attribute(sql)) + span.set_attribute(EXECUTEMANY, True) + # A single statement run with many parameter sets, so unlike + # execute_write_script() there is exactly one operation to name. + operation_name = sql_operation_name(sql) + if operation_name: + span.set_attribute(DB_OPERATION_NAME, operation_name) + results, count = await self.execute_write_fn( + _inner, block=block, request=request + ) + # count is the number of parameter *sets* consumed by + # executemany(), not a row count - executemany returns no rows. + span.set_attribute(PARAM_SETS, count) kwargs["count"] = count return results @@ -321,9 +388,18 @@ class Database: return _run() if not write: # Immutable database - no writes can ever occur, so there is no - # write queue to block; run against a fresh read-only connection + # write queue to block; run against a fresh read-only connection. + # A fresh copy_context() is required per submit (not one shared + # copy reused across calls): concurrent execution of the same + # Context raises "RuntimeError: cannot enter context ... already + # entered". This propagates the caller's otel context (e.g. the + # enclosing db.query span) onto the worker thread. + # + # It also propagates every *other* ContextVar - see the note in + # execute_fn() for why that is safe. + ctx = contextvars.copy_context() return await asyncio.get_running_loop().run_in_executor( - self.ds.executor, _run + self.ds.executor, ctx.run, _run ) # Threaded mode - send to write thread return await self._send_to_write_thread(fn, isolated_connection=True) @@ -428,8 +504,24 @@ class Database: task_id = uuid.uuid5(uuid.NAMESPACE_DNS, "datasette.io") loop = asyncio.get_running_loop() reply_future = loop.create_future() + # Captured here, on the event loop, at enqueue time: the otel + # Context (carrying the enclosing db.query span, if any) and the + # timestamp used to build the db.write.queue_wait span once this + # task is dequeued on the write thread. `block` travels with the + # task too, because it decides whether that context is this task's + # parent or only a link target - see `_execute_writes`. self._write_queue.put( - WriteTask(fn, task_id, loop, reply_future, isolated_connection, transaction) + WriteTask( + fn, + task_id, + loop, + reply_future, + isolated_connection, + transaction, + otel_context_api.get_current(), + time.time_ns(), + block, + ) ) if block: return await reply_future @@ -443,6 +535,16 @@ class Database: conn = None try: conn = self.connect(write=True) + # This warm-up runs before any write has ever been queued, so + # there is no captured caller context to attach - and a raw + # threading.Thread does not inherit the context of whoever started + # it. Spans created by plugin hooks here are therefore roots even + # when the write thread is started from inside invoke_startup(): + # its datasette.startup span is current on the event loop but does + # not cross this thread boundary. Read connections differ - they + # warm up inside executor tasks submitted with copy_context(), so + # their prepare_connection spans do nest under whoever triggered + # them. self.ds._prepare_connection(conn, self.name) except Exception as e: # noqa: BLE001 # Stored and re-raised to whoever queues the next write @@ -457,40 +559,119 @@ class Database: # Best-effort close as the write thread exits pass return - exception = None - result = None - if conn_exception is not None: - exception = conn_exception - elif task.isolated_connection: - try: - isolated_connection = self.connect(write=True) - try: - result = task.fn(isolated_connection) - finally: - isolated_connection.close() - try: - self._all_file_connections.remove(isolated_connection) - except ValueError: - # Was probably a memory connection - pass - except Exception as e: # noqa: BLE001 - # Write thread must survive any task failure or the database wedges - sys.stderr.write(f"{e}\n") - sys.stderr.flush() - exception = e + # `task.block` decides how this task's spans relate to the + # context captured at enqueue time: + # + # - block=True: the caller genuinely awaits the reply, so + # containment is accurate. Restore that context as current + # (attach below) so db.write.queue_wait/db.write.execute parent + # normally to the request that queued them. The token must be + # detached below in `finally` - a leaked token silently + # poisons this thread's ambient context for every write + # processed after it, and a *wrong*-token detach only logs a + # warning rather than raising, so this pairing is load-bearing + # and easy to get wrong silently. + # - block=False: the caller returned already without awaiting, + # so the enqueueing span may already have closed (and + # exported) before this task's spans even start - parenting to + # it would make a child appear to outlive its already-closed + # parent, which OTel allows but which renders badly in most + # trace UIs. The enqueueing request *caused* this write + # without *containing* it, so nothing is attached here - + # instead each write span is started as its own root (explicit + # empty `context=`, so the write thread's ambient context + # cannot supply a parent either) carrying one `Link` back to + # the enqueueing span's context, built once into + # `write_span_kwargs` and spread into every start_span call + # below. + token = None + write_span_kwargs = {} + if task.block: + token = otel_context_api.attach(task.otel_context) else: - try: - if task.transaction: - with conn: - conn.execute("BEGIN IMMEDIATE") - result = task.fn(conn) - else: - result = task.fn(conn) - except Exception as e: # noqa: BLE001 - sys.stderr.write(f"{e}\n") - sys.stderr.flush() - exception = e - _deliver_write_result(task, result, exception) + enqueueing_span_context = get_current_span( + task.otel_context + ).get_span_context() + # No attributes on the link: there is only one kind of link + # here, so naming the relationship would be a constant that + # carries no information a consumer does not already have + # from the link's existence. + links = ( + [Link(enqueueing_span_context)] + if enqueueing_span_context.is_valid + else [] + ) + write_span_kwargs = { + "context": otel_context_api.Context(), + "links": links, + } + try: + exception = None + result = None + # Explicit start_time/end_time rather than a `with` block: + # this span's duration is the time the task actually spent + # waiting in the queue (enqueue -> dequeue), not the near- + # zero time spent constructing/ending the span object here. + tracer.start_span( + DB_WRITE_QUEUE_WAIT, + start_time=task.enqueued_at_ns, + **write_span_kwargs, + ).end(end_time=time.time_ns()) + if conn_exception is not None: + # fn never runs in this branch, so there is nothing to + # wrap in a db.write.execute span. + exception = conn_exception + elif task.isolated_connection: + try: + with tracer.start_as_current_span( + DB_WRITE_EXECUTE, **write_span_kwargs + ) as span: + span.set_attribute( + ISOLATED_CONNECTION, + task.isolated_connection, + ) + span.set_attribute(TRANSACTION, task.transaction) + isolated_connection = self.connect(write=True) + try: + result = task.fn(isolated_connection) + finally: + isolated_connection.close() + try: + self._all_file_connections.remove( + isolated_connection + ) + except ValueError: + # Was probably a memory connection + pass + except Exception as e: # noqa: BLE001 + # Write thread must survive any task failure or the database wedges + sys.stderr.write(f"{e}\n") + sys.stderr.flush() + exception = e + else: + try: + with tracer.start_as_current_span( + DB_WRITE_EXECUTE, **write_span_kwargs + ) as span: + span.set_attribute( + ISOLATED_CONNECTION, + task.isolated_connection, + ) + span.set_attribute(TRANSACTION, task.transaction) + if task.transaction: + with conn: + conn.execute("BEGIN IMMEDIATE") + result = task.fn(conn) + else: + result = task.fn(conn) + except Exception as e: # noqa: BLE001 + sys.stderr.write(f"{e}\n") + sys.stderr.flush() + exception = e + _deliver_write_result(task, result, exception) + finally: + if token is not None: + otel_context_api.detach(token) async def execute_fn(self, fn): self._check_not_closed() @@ -512,7 +693,29 @@ class Database: with self._pending_execute_futures_lock: self._check_not_closed() - future = self.ds.executor.submit(in_thread) + # A fresh copy_context() is required per submit (not one shared + # copy reused across calls): concurrent execution of the same + # Context raises "RuntimeError: cannot enter context ... + # already entered". This propagates the caller's otel context + # (e.g. the enclosing db.query span) onto the worker thread. + # + # copy_context() is not selective: it also carries Datasette's own + # ContextVars - _skip_permission_checks and _permission_check_cache + # (datasette/permissions.py), _in_datasette_client (app.py) and, + # until the hand-rolled tracer goes, trace_task_id (tracer.py) - + # into worker threads, where they previously took their defaults. + # That is safe, for two reasons. Nothing reads them on a worker + # thread: the permission code that reads the first two is async and + # only ever runs on the event loop. And Context.run() restores the + # thread's previous context when the callable returns, so a value + # cannot outlive the submit that carried it and reach the next task + # on this shared pool - "skip permission checks" in particular can + # never bleed from one request into another's query. Where a value + # would be read - a plugin calling datasette.in_client() or trace() + # from inside an execute_fn callable - seeing the submitting + # request's value is the more accurate answer, not a leak. + ctx = contextvars.copy_context() + future = self.ds.executor.submit(ctx.run, in_thread) self._pending_execute_futures.add(future) future.add_done_callback(self._remove_pending_execute_future) return await asyncio.wrap_future(future) @@ -525,48 +728,149 @@ class Database: custom_time_limit=None, page_size=None, log_sql_errors=True, + table=None, ): - """Executes sql against db_name in a thread""" + """Executes sql against db_name in a thread + + `table`, if passed, is recorded as the `db.collection.name` span + attribute. It exists for callers that already know which table the + query targets - the table and row views - and is never derived from + `sql` itself: deriving it would be a parse, and on an instance where + anyone can create a table the resulting value set has no ceiling. + """ self._check_not_closed() page_size = page_size or self.ds.page_size + time_limit_ms = self.ds.sql_time_limit_ms + # A caller that hands in a budget shorter than the instance-wide + # sql_time_limit_ms is saying "this may not finish, and that is an + # answer I can use" - and every such caller in core does treat the + # timeout as normal: table_counts() stores None per table, facet + # suggestion moves on to the next column, autocomplete falls back to a + # prefix query. Those timeouts are therefore not span errors. Without + # this, the homepage alone emits one red span per table (it counts + # every table under a 10ms budget) on every single hit. + # + # A query that runs out the instance-wide limit is a different event - + # nobody asked for a short budget, so it stays an error. + timeout_expected = bool(custom_time_limit) and custom_time_limit < time_limit_ms + if timeout_expected: + time_limit_ms = custom_time_limit def sql_operation_in_thread(conn): - time_limit_ms = self.ds.sql_time_limit_ms - if custom_time_limit and custom_time_limit < time_limit_ms: - time_limit_ms = custom_time_limit - - with sqlite_timelimit(conn, time_limit_ms): + # This span is created inside the worker thread. Its parent is + # resolved from the ambient otel context, which was propagated + # onto this thread via copy_context() at the executor.submit() + # boundary in execute_fn() (or run_in_executor() for immutable + # databases) - so it parents correctly to the enclosing + # db.query span despite running on a different thread. + # + # Exception handling is explicit rather than left to the context + # manager's flags, which apply to every exception type alike. This + # span needs to tell two apart: an expected timeout is never an + # error, while a genuine SQL failure is one unless the caller + # passed log_sql_errors=False, meaning it was probing and treats + # failure as an expected answer. Without the latter, facet + # suggestion marks two spans per text column as failed on every + # table page; without the former, so does every homepage hit. + with tracer.start_as_current_span( + DB_QUERY_EXECUTE, + record_exception=False, + set_status_on_exception=False, + ) as execute_span: try: - cursor = conn.cursor() - cursor.execute(sql, params if params is not None else {}) - max_returned_rows = self.ds.max_returned_rows - if max_returned_rows == page_size: - max_returned_rows += 1 - if max_returned_rows and truncate: - rows = cursor.fetchmany(max_returned_rows + 1) - truncated = len(rows) > max_returned_rows - rows = rows[:max_returned_rows] - else: - rows = cursor.fetchall() - truncated = False - except (sqlite3.OperationalError, sqlite3.DatabaseError) as e: - if e.args == ("interrupted",): - raise QueryInterrupted(e, sql, params) + with sqlite_timelimit(conn, time_limit_ms): + try: + cursor = conn.cursor() + cursor.execute(sql, params if params is not None else {}) + max_returned_rows = self.ds.max_returned_rows + if max_returned_rows == page_size: + max_returned_rows += 1 + if max_returned_rows and truncate: + rows = cursor.fetchmany(max_returned_rows + 1) + truncated = len(rows) > max_returned_rows + rows = rows[:max_returned_rows] + else: + rows = cursor.fetchall() + truncated = False + except (sqlite3.OperationalError, sqlite3.DatabaseError) as e: + if e.args == ("interrupted",): + raise QueryInterrupted(e, sql, params) + if log_sql_errors: + sys.stderr.write( + f"ERROR: conn={conn}, sql = {sql!r}, params = {params}: {e}\n" + ) + sys.stderr.flush() + raise + except QueryInterrupted as e: + if not timeout_expected: + execute_span.record_exception(e) + execute_span.set_status(Status(StatusCode.ERROR, str(e))) + raise + except Exception as e: if log_sql_errors: - sys.stderr.write( - f"ERROR: conn={conn}, sql = {sql!r}, params = {params}: {e}\n" - ) - sys.stderr.flush() + execute_span.record_exception(e) + execute_span.set_status(Status(StatusCode.ERROR, str(e))) raise - if truncate: - return Results(rows, truncated, cursor.description) + if truncate: + return Results(rows, truncated, cursor.description) - else: - return Results(rows, False, cursor.description) + else: + return Results(rows, False, cursor.description) - with trace("sql", database=self.name, sql=sql.strip(), params=params): - results = await self.execute_fn(sql_operation_in_thread) + # SIM117 wants these two context managers merged. They are kept nested + # deliberately: the hand-rolled tracer's wrapper is on its way out, and + # nesting makes removing it a single-line deletion. + with trace( # noqa: SIM117 + "sql", database=self.name, sql=sql.strip(), params=params + ): + # Exception handling is explicit rather than left to the context + # manager's defaults, so that callers passing log_sql_errors=False + # can be honoured - see the comment on the generic handler below. + with tracer.start_as_current_span( + DB_QUERY, + kind=DB_QUERY.kind, + record_exception=False, + set_status_on_exception=False, + ) as span: + span.set_attribute(DB_SYSTEM, "sqlite") + span.set_attribute(DB_NAMESPACE, self.name) + span.set_attribute(DB_QUERY_TEXT, sql_attribute(sql)) + span.set_attribute(TIME_LIMIT_MS, time_limit_ms) + operation_name = sql_operation_name(sql) + if operation_name: + span.set_attribute(DB_OPERATION_NAME, operation_name) + if table: + span.set_attribute(DB_COLLECTION_NAME, table) + if params: + span.set_attribute(PARAM_COUNT, len(params)) + try: + results = await self.execute_fn(sql_operation_in_thread) + except QueryInterrupted as e: + # datasette.interrupted is set either way - it is the + # signal worth having. Only the ERROR status is + # conditional; see the timeout_expected comment above. + span.set_attribute(INTERRUPTED, True) + if not timeout_expected: + span.set_status(Status(StatusCode.ERROR, str(e))) + span.record_exception(e) + raise + except Exception as e: + # log_sql_errors=False means the caller is probing and + # treats failure as an expected answer, not an error. + # Facet suggestion is the big one: it runs json_type() + # against every column precisely to find out which ones + # raise, so a table with N text columns would otherwise + # mark N queries per page as failed - burying real errors + # and setting off any alerting based on span status. + if log_sql_errors: + span.record_exception(e) + span.set_status(Status(StatusCode.ERROR, str(e))) + else: + span.set_attribute(SQL_ERROR_SUPPRESSED, True) + raise + span.set_attribute(TRUNCATED, results.truncated) + span.set_attribute(ROWS_RETURNED, len(results.rows)) return results @property @@ -854,16 +1158,28 @@ def _apply_write_wrapper(fn, wrapper_factory, track_event): class WriteTask: __slots__ = ( + "block", + "enqueued_at_ns", "fn", "isolated_connection", "loop", + "otel_context", "reply_future", "task_id", "transaction", ) def __init__( - self, fn, task_id, loop, reply_future, isolated_connection, transaction + self, + fn, + task_id, + loop, + reply_future, + isolated_connection, + transaction, + otel_context, + enqueued_at_ns, + block, ): self.fn = fn self.task_id = task_id @@ -871,6 +1187,14 @@ class WriteTask: self.reply_future = reply_future self.isolated_connection = isolated_connection self.transaction = transaction + self.otel_context = otel_context + self.enqueued_at_ns = enqueued_at_ns + # Whether the enqueueing caller awaits the reply future. Decides how + # `_execute_writes` relates this task's spans to `otel_context`: + # parent (block=True) or span-link target (block=False). See the + # comment at the WriteTask construction site in + # `_send_to_write_thread`. + self.block = block def _deliver_write_result(task, result, exception): diff --git a/datasette/telemetry.py b/datasette/telemetry.py new file mode 100644 index 00000000..3a205cee --- /dev/null +++ b/datasette/telemetry.py @@ -0,0 +1,117 @@ +""" +OpenTelemetry integration for Datasette core. + +Core depends on `opentelemetry-api` only. It never creates a +`TracerProvider`, never configures an exporter, and never touches +sampling - that is the responsibility of whoever is running Datasette +(an `opentelemetry-instrument` agent, a future plugin, or a test +harness). + +With no provider installed every span produced here is a +`NonRecordingSpan`. That is not free - a table page emits ~58 spans - +but it is below what an end-to-end page benchmark can resolve: measured +across 15 runs of a 5,000-row table page, the median moved 9.80ms to +9.98ms while run-to-run spread was 1.4ms. Installing an SDK provider is +what costs something measurable. +""" + +import re + +from opentelemetry import trace as otel_trace + +from .version import __version__ + +# The semantic-convention version whose spellings this instrumentation +# actually emits. Deliberately NOT the latest release. +# +# A schema URL is a machine-readable claim: a consumer doing schema +# translation replays the renames between the declared version and the one +# it wants, so the claim has to name the version whose spellings are on the +# wire. A wrong one makes translation wrong rather than merely uninformative. +# +# Datasette emits `db.system`, which was renamed to `db.system.name` in +# semconv 1.30.0. Everything else it emits (`db.namespace`, `db.query.text`, +# `db.operation.name`, `db.collection.name`) has been current since 1.26.0. +# So 1.29.0 is the highest version at which every name emitted here is the +# current spelling. Everything under `datasette.*` is Datasette's own and +# outside semconv, so it is unaffected either way. +# +# Declaring 1.43.0 would be false about `db.system`, and would actively STOP +# a consumer translating it forward, because it asserts the rename already +# happened. Bump this deliberately, in the same commit as the attribute +# renames it implies - it is a claim about the names, not decoration. +SCHEMA_URL = "https://opentelemetry.io/schemas/1.29.0" + +tracer = otel_trace.get_tracer("datasette", __version__, schema_url=SCHEMA_URL) + +MAX_SQL_LENGTH = 2048 + + +def sql_attribute(sql: str) -> str: + "Truncate SQL text so it is safe to attach to a span as an attribute." + sql = sql.strip() + if len(sql) <= MAX_SQL_LENGTH: + return sql + return sql[:MAX_SQL_LENGTH] + "…[truncated]" + + +# db.operation.name is the leading keyword of a statement matched against a +# fixed allowlist - deliberately not a parse. +# +# This runs against arbitrary user-supplied SQL (the `?sql=` query string, +# canned queries, anything typed into the query editor), and the attribute is +# a candidate dimension on a query-duration metric in a later phase. A metric +# series is keyed by its attribute values, so echoing back an arbitrary first +# token would let one visitor's typo mint a new, permanent series. The +# allowlist bounds that at a fixed, small set regardless of what anyone sends. +DB_OPERATION_ALLOWLIST = frozenset( + { + "SELECT", + "INSERT", + "UPDATE", + "DELETE", + "CREATE", + "DROP", + "ALTER", + "PRAGMA", + "EXPLAIN", + "REPLACE", + "VACUUM", + "ANALYZE", + "WITH", + } +) + +_LEADING_KEYWORD = re.compile(r"^\s*([A-Za-z]+)") + + +def sql_operation_name(sql: str) -> str | None: + """ + The statement's leading keyword, if it is one we recognise. + + Returns None - never a guess - for anything not on the allowlist, + including a statement that opens with a comment or with punctuation such + as the "(" of a parenthesised SELECT. + + Known limitation: a statement beginning with a CTE reports `WITH` rather + than the operation inside it, and a substantial share of Datasette's own + reads take that form. Extracting more than the leading keyword means + handling comment stripping, parenthesised `(SELECT ...) UNION` and + compound names like `CREATE TABLE` - each a special case a hand-rolled + matcher would accrete and eventually get wrong. Omitting a name beats + guessing at one. + + Only safe to call with a single statement: `execute_write_script()` runs + several separated by semicolons, and semantic conventions say + `db.operation.name` "SHOULD NOT be extracted from db.query.text, when the + database system supports query text with multiple operations in non-batch + operations" - so that call site does not use this at all rather than + reporting only the first statement's operation. + """ + match = _LEADING_KEYWORD.match(sql) + if not match: + return None + keyword = match.group(1).upper() + if keyword in DB_OPERATION_ALLOWLIST: + return keyword + return None diff --git a/datasette/telemetry_registry.py b/datasette/telemetry_registry.py new file mode 100644 index 00000000..2d0692a8 --- /dev/null +++ b/datasette/telemetry_registry.py @@ -0,0 +1,273 @@ +""" +The single source of truth for every span and span attribute that Datasette +core emits. + +Three things read this module, which is the point of it existing: + +1. **The instrumentation itself.** `Attribute` and `SpanName` subclass `str`, + so a registry entry *is* the string OpenTelemetry wants. Call sites pass + `DB_NAMESPACE` where they used to pass `"db.namespace"` - no wrapper API + over the OTel calls, no parallel structure to keep in step, and a typo is + now an `ImportError` instead of a silently misnamed attribute. + +2. **The documentation.** `docs/telemetry_doc.py` renders the span reference + in `docs/internals.rst` from these definitions using cog, and + `cog --check` runs in CI - so the docs cannot drift from the code. + +3. **A conformance test.** `tests/test_telemetry_registry.py` makes real + requests, collects every span and attribute actually emitted, and compares + both directions: emitted-but-unregistered catches instrumentation added + without documentation, registered-but-never-emitted catches documentation + describing something that no longer exists. Neither the type system nor + the generated docs can catch that second case. +""" + +from opentelemetry.trace import SpanKind + + +class Attribute(str): + """ + A span attribute key, carrying its own documentation. + + Subclasses `str` so it can be handed straight to `set_attribute()`. + """ + + __slots__ = ("description", "optional") + + def __new__(cls, name, description, optional=False): + self = super().__new__(cls, name) + self.description = description + self.optional = optional + return self + + def __repr__(self): + return f"Attribute({str(self)!r})" + + +class SpanName(str): + "A span name, carrying its documentation and the attributes it may set." + + __slots__ = ("attributes", "description", "kind", "prefix") + + def __new__( + cls, name, description, attributes=(), prefix=False, kind=SpanKind.INTERNAL + ): + self = super().__new__(cls, name) + self.description = description + self.attributes = tuple(attributes) + # True for a span family whose emitted names carry a variable suffix, + # so the conformance test matches by prefix rather than equality. + # Nothing sets it yet. + self.prefix = prefix + # SpanKind.INTERNAL by default - every span Datasette emits describes + # its own internal work. db.query is the one exception: it is a real + # database call, so semantic conventions (and trace UIs, which key + # their database styling off this) expect SpanKind.CLIENT. + self.kind = kind + return self + + def __repr__(self): + return f"SpanName({str(self)!r})" + + +# --- Attributes ----------------------------------------------------------- +# +# Shared attributes are defined once and referenced by every span that sets +# them, so "which spans carry db.namespace?" is answerable by grep. + +DB_SYSTEM = Attribute("db.system", "Always ``sqlite``.") +DB_NAMESPACE = Attribute("db.namespace", "Name of the database being queried.") +DB_QUERY_TEXT = Attribute( + "db.query.text", + "The SQL, truncated to 2048 characters. Never the parameter values.", +) +DB_OPERATION_NAME = Attribute( + "db.operation.name", + "The statement's leading keyword - ``SELECT``, ``INSERT``, ``CREATE``, and " + "so on - matched against a small fixed allowlist. Omitted rather than set " + "to an arbitrary value: the allowlist exists because this attribute is a " + "candidate dimension for a query-duration metric in a later phase, and " + "echoing an unrecognised first token from user-supplied SQL would be an " + "unbounded-cardinality hazard. Also omitted for " + "``execute_write_script()``, which runs multiple statements - per " + "semantic conventions, the operation name should not be extracted from " + "query text that can contain more than one operation. Note that a " + "statement beginning with a CTE reports ``WITH``, not the operation " + "inside it - a substantial share of Datasette's own reads take that " + "form. Resolving it further would mean parsing.", + optional=True, +) +DB_COLLECTION_NAME = Attribute( + "db.collection.name", + "The primary table, set only where the view already knows it - the table " + "and row pages. Omitted for arbitrary ``?sql=`` queries, where determining " + "the table would mean parsing the query.", + optional=True, +) + +PARAM_COUNT = Attribute( + "datasette.param_count", + "Number of bound parameters. Recorded instead of the values themselves.", + optional=True, +) +PARAM_SETS = Attribute( + "datasette.param_sets", + "Number of parameter sets consumed by ``execute_write_many()``. Not a row " + "count - ``executemany()`` returns no rows. The parameter values " + "themselves are never recorded: that sequence can hold thousands of rows.", + optional=True, +) +TIME_LIMIT_MS = Attribute( + "datasette.time_limit_ms", + "The :ref:`setting_sql_time_limit_ms` value this query ran under. Set on " + "reads, which are the queries that time limit applies to.", + optional=True, +) +ROWS_RETURNED = Attribute( + "datasette.rows_returned", + "Number of rows a read returned. Set on the read path only, and only when " + "the read succeeded.", + optional=True, +) +TRUNCATED = Attribute( + "datasette.truncated", + "True if the result was cut short by :ref:`setting_max_returned_rows`.", + optional=True, +) +INTERRUPTED = Attribute( + "datasette.interrupted", + "True if the query was cancelled for exceeding the time limit. The span " + "status is also set to ``ERROR``, unless the caller asked for a budget " + "shorter than :ref:`setting_sql_time_limit_ms` - as table counts, facet " + "suggestion and autocomplete all do - in which case running out of time " + "is an expected answer rather than a failure and the status is left " + "unset.", + optional=True, +) +SQL_ERROR_SUPPRESSED = Attribute( + "datasette.sql_error_suppressed", + "True when the query failed but the caller passed ``log_sql_errors=False``, " + "meaning it was probing and treats failure as an expected answer. Facet " + "suggestion does this against every column.", + optional=True, +) +EXECUTESCRIPT = Attribute( + "datasette.executescript", + "True for ``execute_write_script()``, which runs multiple statements.", + optional=True, +) +EXECUTEMANY = Attribute( + "datasette.executemany", + "True for ``execute_write_many()``, which runs one statement against many " + "parameter sets.", + optional=True, +) +ISOLATED_CONNECTION = Attribute( + "datasette.isolated_connection", + "True if the write ran on its own connection rather than the shared write " + "connection.", +) +TRANSACTION = Attribute( + "datasette.transaction", + "False for statements such as ``VACUUM`` that cannot run inside a transaction.", +) + + +# --- Spans ---------------------------------------------------------------- + +DB_QUERY = SpanName( + "db.query", + "A SQL operation issued by Datasette, covering the full round trip " + "including any time spent queued for a thread.", + ( + DB_SYSTEM, + DB_NAMESPACE, + DB_QUERY_TEXT, + DB_OPERATION_NAME, + DB_COLLECTION_NAME, + PARAM_COUNT, + PARAM_SETS, + TIME_LIMIT_MS, + ROWS_RETURNED, + TRUNCATED, + INTERRUPTED, + SQL_ERROR_SUPPRESSED, + EXECUTESCRIPT, + EXECUTEMANY, + ), + kind=SpanKind.CLIENT, +) + +DB_QUERY_EXECUTE = SpanName( + "db.query.execute", + "The read executing inside a SQL worker thread. Child of ``db.query``; the " + "gap between the two is time spent waiting for a thread.", +) + +DB_WRITE_QUEUE_WAIT = SpanName( + "db.write.queue_wait", + "Time a write spent waiting in its database's write queue before the write " + "thread picked it up. Child of ``db.query`` for a ``block=True`` write, " + "where the caller awaits the write and containment is accurate. For a " + "``block=False`` write the caller does not await it - the enqueueing " + "request *caused* the write without *containing* it, and the write's " + "spans can outlive the request's own - so this is a root span instead, " + "carrying an OpenTelemetry link back to the enqueueing span rather than " + "a parent. A link records causation without asserting containment, which " + "is exactly the distinction here.", +) + +DB_WRITE_EXECUTE = SpanName( + "db.write.execute", + "The write executing on the write thread. Child of ``db.query`` for a " + "``block=True`` write; for ``block=False`` a root span with a link back " + "to the enqueueing span instead - see ``db.write.queue_wait`` above.", + (ISOLATED_CONNECTION, TRANSACTION), +) + +STARTUP = SpanName( + "datasette.startup", + "``invoke_startup()`` running: ``register_events``, ``register_actions``, " + "``register_column_types``, ``prepare_jinja2_environment``, internal-database " + "schema catalog refresh (including the ``prepare_connection`` warm-up this " + "triggers for each database touched for the first time), saved queries, " + "column type config and the ``startup`` hook. Runs once per process, before " + "any request exists, so without this span every child it creates would be " + "its own orphan root trace. A connection warmed later - lazily, the first " + "time a *request* touches a new database or thread - nests under that " + "request's own span instead, not under this one, since this span has " + "already ended by then.", +) + +SPANS = ( + DB_QUERY, + DB_QUERY_EXECUTE, + DB_WRITE_QUEUE_WAIT, + DB_WRITE_EXECUTE, + STARTUP, +) + + +def span_for(emitted_name): + """ + Resolve an emitted span name to its registry entry, or None. + + Handles span families whose emitted names carry a suffix that is not + knowable in advance - `prefix=True` entries. Phase 1 has none, but the + lookup is what the conformance test calls, so it lives here rather than + in the test. + """ + for span in SPANS: + if span.prefix: + if emitted_name.startswith(span): + return span + elif emitted_name == span: + return span + return None + + +def attribute_allowed(span, emitted_key): + "Whether `emitted_key` is a registered attribute of `span`." + if span is None: + return False + return emitted_key in span.attributes diff --git a/datasette/views/row.py b/datasette/views/row.py index b1388299..b5196a83 100644 --- a/datasette/views/row.py +++ b/datasette/views/row.py @@ -407,7 +407,7 @@ class RowView(BaseView): raise Forbidden("You do not have permission to view this table") results = await resolved.db.execute( - resolved.sql, resolved.params, truncate=True + resolved.sql, resolved.params, truncate=True, table=table ) columns = [r[0] for r in results.description] rows = list(results.rows) @@ -652,6 +652,9 @@ class RowView(BaseView): ] ) try: + # No table= here: this counts incoming references across every + # foreign key pointing at this row, so it spans many tables and + # there is no single value db.collection.name could take. rows = list(await db.execute(sql, {"id": pk_values[0]})) except QueryInterrupted: # Almost certainly hit the timeout @@ -840,7 +843,7 @@ class RowUpdateView(BaseView): returned_row = None if data.get("return"): results = await resolved.db.execute( - resolved.sql, resolved.params, truncate=True + resolved.sql, resolved.params, truncate=True, table=resolved.table ) returned_row = results.dicts()[0] result["rows"] = [returned_row] @@ -858,7 +861,7 @@ class RowUpdateView(BaseView): message_row = returned_row if message_row is None: results = await resolved.db.execute( - resolved.sql, resolved.params, truncate=True + resolved.sql, resolved.params, truncate=True, table=resolved.table ) message_row = results.first() self.ds.add_message( diff --git a/datasette/views/table.py b/datasette/views/table.py index 7c814b27..6d920fd8 100644 --- a/datasette/views/table.py +++ b/datasette/views/table.py @@ -1170,6 +1170,7 @@ class TableInsertView(BaseView): "rowid, " if pks == ["rowid"] else "", table_name, where_clause ), args, + table=table_name, ) result["rows"] = fetched_rows.dicts() else: @@ -1382,7 +1383,9 @@ class TableDropView(BaseView): "database": database_name, "table": table_name, "row_count": ( - await db.execute(f"select count(*) from [{table_name}]") + await db.execute( + f"select count(*) from [{table_name}]", table=table_name + ) ).single_value(), "message": 'Pass "confirm": true to confirm', }, @@ -1576,7 +1579,10 @@ class TableAutocompleteView(BaseView): try: results = await db.execute( - sql, params, custom_time_limit=AUTOCOMPLETE_TIME_LIMIT_MS + sql, + params, + custom_time_limit=AUTOCOMPLETE_TIME_LIMIT_MS, + table=table_name, ) except QueryInterrupted: fallback_where = _autocomplete_prefix_like(pks[0]) @@ -1597,6 +1603,7 @@ class TableAutocompleteView(BaseView): fallback_sql, params, custom_time_limit=AUTOCOMPLETE_TIME_LIMIT_MS, + table=table_name, ) except QueryInterrupted: return Response.json({"ok": True, "rows": []}) @@ -2163,7 +2170,9 @@ async def table_view_data( # Execute the main query! try: - results = await db.execute(sql, params, truncate=True, **extra_args) + results = await db.execute( + sql, params, truncate=True, table=table_name, **extra_args + ) except (sqlite3.OperationalError, InvalidSql) as e: raise DatasetteError(str(e), title="Invalid SQL", status=400) @@ -2439,6 +2448,7 @@ async def _next_value_and_url( await db.execute( prefix_lookup_sql, {**{f"pk{i}": rows[-2][pk] for i, pk in enumerate(pks)}}, + table=table_name, ) ).single_value() if isinstance(prefix, dict) and "value" in prefix: diff --git a/docs/changelog.rst b/docs/changelog.rst index 66a7caab..cec8e92d 100644 --- a/docs/changelog.rst +++ b/docs/changelog.rst @@ -4,6 +4,16 @@ Changelog ========= +.. _v_unreleased: + +Unreleased +---------- + +- Datasette's database layer now emits `OpenTelemetry `__ spans: one per query, covering the full round trip including time spent waiting for a SQL worker thread, plus separate child spans for the execution itself and for time spent in the write queue. Datasette core depends on ``opentelemetry-api`` only and never installs an SDK provider, an exporter or a sampler, so there is no effect and no measurable overhead unless tracing is switched on externally - normally with the standard ``opentelemetry-instrument`` agent. See :ref:`internals_telemetry`. (:issue:`1730`) +- :ref:`db.execute(sql, ..., table=None) ` has a new optional ``table=`` parameter, naming the table a query is about so it can be recorded on that query's OpenTelemetry span. It has no effect on query execution, and Datasette never derives it from the SQL. (:issue:`1730`) + +Nothing is removed by this change: the ``?_trace=1`` query string parameter, the ``trace_debug`` setting and the :ref:`internals_tracer` module all continue to work as before. + .. _v1_0_a38: 1.0a38 (2026-08-06) diff --git a/docs/internals.rst b/docs/internals.rst index d2bd46ef..31666e0e 100644 --- a/docs/internals.rst +++ b/docs/internals.rst @@ -1963,6 +1963,9 @@ Executes a SQL query against the database and returns the resulting rows (see :r ``log_sql_errors`` - boolean Should any SQL errors be logged to the console in addition to being raised as an error? Defaults to ``True``. +``table`` - string + The name of the table this query is about, if the caller already knows it. This has no effect on how the query executes - it is recorded as the ``db.collection.name`` attribute on the :ref:`OpenTelemetry span ` for the query. Datasette never derives this from the SQL, so leave it unset for queries that do not have one obvious table. + .. _database_results: Results @@ -2313,6 +2316,133 @@ The ``Database`` class also provides properties and methods for introspecting th } } +.. _internals_telemetry: + +OpenTelemetry +============= + +Datasette core depends on `opentelemetry-api `__ only. It never creates a ``TracerProvider``, never configures an exporter and never sets a sampler. With no OpenTelemetry SDK provider installed, every span described below is a no-op ``NonRecordingSpan``: nothing is recorded, nothing is exported, and the cost does not show up in page latency. Benchmarking a table page with and without this instrumentation, the median moved by less than the run-to-run variation of the benchmark itself. + +Turning tracing on is entirely an operational decision made outside of Datasette itself: run Datasette under the standard ``opentelemetry-instrument`` agent, or embed Datasette inside a host application that installs its own provider. + +Everything Datasette emits carries the instrumentation scope ``datasette``, versioned with the running Datasette version and declaring the `semantic conventions schema `__ its attribute names follow. + +This is separate from, and does not replace, the built-in :ref:`internals_tracer` mechanism behind ``?_trace=1`` and the :ref:`setting_trace_debug` setting. Both continue to work exactly as before. + +.. _internals_telemetry_turning_on: + +Turning tracing on +------------------ + +Install an OpenTelemetry SDK, an exporter and the instrumentation agent, then launch Datasette through ``opentelemetry-instrument``: + +.. code-block:: bash + + pip install opentelemetry-distro opentelemetry-exporter-otlp + OTEL_SERVICE_NAME=datasette \ + OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 \ + OTEL_METRICS_EXPORTER=none \ + OTEL_LOGS_EXPORTER=none \ + opentelemetry-instrument datasette mydb.db + +Point ``OTEL_EXPORTER_OTLP_ENDPOINT`` at whichever tracing backend you use. To print spans straight to the terminal instead, with no backend at all, drop that variable and set ``OTEL_TRACES_EXPORTER=console`` in its place. + +A few things catch people out the first time: + +.. warning:: + ``OTEL_TRACES_EXPORTER=console datasette mydb.db`` produces **nothing**. That environment variable is read by the OpenTelemetry SDK's auto-configuration, which only runs when the ``opentelemetry-instrument`` agent wraps the process. Datasette core installs no provider, so a plain ``datasette`` process emits nothing at all, whatever ``OTEL_`` variables are set. + +Spans do not appear immediately. The SDK's default ``BatchSpanProcessor`` flushes on a timer, every 5 seconds. Either wait, or stop the process - shutdown triggers a final flush - or set ``OTEL_BSP_SCHEDULE_DELAY=1000`` while you are experimenting. That last one is for demos, not for production. + +Always set ``OTEL_SERVICE_NAME``. Without it the SDK's default resource reports a ``service.name`` of ``unknown_service``, and your traces will be filed under that instead of under a name you can search for. + +Setting ``OTEL_METRICS_EXPORTER=none`` and ``OTEL_LOGS_EXPORTER=none`` is worth doing unless your backend accepts those signals too - ``opentelemetry-distro`` defaults every signal to OTLP, and a traces-only backend will reject the other two noisily. Datasette itself emits no metrics and no logs through OpenTelemetry. + +Span reference +-------------- + +Datasette emits five spans. Four of them describe the database layer - one per query, one for the work that query does inside a SQL worker thread, and two more for the write queue - and the fifth covers startup. Attribute names use the ``datasette.*`` prefix for Datasette-specific data, alongside standard OpenTelemetry attributes such as ``db.system``. + +This reference is generated from ``datasette/telemetry_registry.py``, the single source of truth for every span and attribute Datasette emits. A conformance test makes real requests and compares what is actually emitted against that registry in both directions, so nothing here is hand-maintained and nothing can silently drift out of date. + +Spans are ``SpanKind.INTERNAL`` unless a kind is listed below. Only ``db.query`` is ``CLIENT``: it is the one span that represents a call to a database rather than Datasette's own work, and trace UIs use the kind to decide whether to render a span as a database call. Its children stay ``INTERNAL`` because they are Datasette's decomposition of that one query - marking them ``CLIENT`` too would make a single query look like several database calls to anything counting by kind. + +.. [[[cog + from telemetry_doc import spans + spans(cog) +.. ]]] + +``db.query`` + A SQL operation issued by Datasette, covering the full round trip including any time spent queued for a thread. + + Kind: ``CLIENT``. + + Attributes: + + - ``db.system`` - Always ``sqlite``. + - ``db.namespace`` - Name of the database being queried. + - ``db.query.text`` - The SQL, truncated to 2048 characters. Never the parameter values. + - ``db.operation.name`` *(optional)* - The statement's leading keyword - ``SELECT``, ``INSERT``, ``CREATE``, and so on - matched against a small fixed allowlist. Omitted rather than set to an arbitrary value: the allowlist exists because this attribute is a candidate dimension for a query-duration metric in a later phase, and echoing an unrecognised first token from user-supplied SQL would be an unbounded-cardinality hazard. Also omitted for ``execute_write_script()``, which runs multiple statements - per semantic conventions, the operation name should not be extracted from query text that can contain more than one operation. Note that a statement beginning with a CTE reports ``WITH``, not the operation inside it - a substantial share of Datasette's own reads take that form. Resolving it further would mean parsing. + - ``db.collection.name`` *(optional)* - The primary table, set only where the view already knows it - the table and row pages. Omitted for arbitrary ``?sql=`` queries, where determining the table would mean parsing the query. + - ``datasette.param_count`` *(optional)* - Number of bound parameters. Recorded instead of the values themselves. + - ``datasette.param_sets`` *(optional)* - Number of parameter sets consumed by ``execute_write_many()``. Not a row count - ``executemany()`` returns no rows. The parameter values themselves are never recorded: that sequence can hold thousands of rows. + - ``datasette.time_limit_ms`` *(optional)* - The :ref:`setting_sql_time_limit_ms` value this query ran under. Set on reads, which are the queries that time limit applies to. + - ``datasette.rows_returned`` *(optional)* - Number of rows a read returned. Set on the read path only, and only when the read succeeded. + - ``datasette.truncated`` *(optional)* - True if the result was cut short by :ref:`setting_max_returned_rows`. + - ``datasette.interrupted`` *(optional)* - True if the query was cancelled for exceeding the time limit. The span status is also set to ``ERROR``, unless the caller asked for a budget shorter than :ref:`setting_sql_time_limit_ms` - as table counts, facet suggestion and autocomplete all do - in which case running out of time is an expected answer rather than a failure and the status is left unset. + - ``datasette.sql_error_suppressed`` *(optional)* - True when the query failed but the caller passed ``log_sql_errors=False``, meaning it was probing and treats failure as an expected answer. Facet suggestion does this against every column. + - ``datasette.executescript`` *(optional)* - True for ``execute_write_script()``, which runs multiple statements. + - ``datasette.executemany`` *(optional)* - True for ``execute_write_many()``, which runs one statement against many parameter sets. + +``db.query.execute`` + The read executing inside a SQL worker thread. Child of ``db.query``; the gap between the two is time spent waiting for a thread. + + No attributes. + +``db.write.queue_wait`` + Time a write spent waiting in its database's write queue before the write thread picked it up. Child of ``db.query`` for a ``block=True`` write, where the caller awaits the write and containment is accurate. For a ``block=False`` write the caller does not await it - the enqueueing request *caused* the write without *containing* it, and the write's spans can outlive the request's own - so this is a root span instead, carrying an OpenTelemetry link back to the enqueueing span rather than a parent. A link records causation without asserting containment, which is exactly the distinction here. + + No attributes. + +``db.write.execute`` + The write executing on the write thread. Child of ``db.query`` for a ``block=True`` write; for ``block=False`` a root span with a link back to the enqueueing span instead - see ``db.write.queue_wait`` above. + + Attributes: + + - ``datasette.isolated_connection`` - True if the write ran on its own connection rather than the shared write connection. + - ``datasette.transaction`` - False for statements such as ``VACUUM`` that cannot run inside a transaction. + +``datasette.startup`` + ``invoke_startup()`` running: ``register_events``, ``register_actions``, ``register_column_types``, ``prepare_jinja2_environment``, internal-database schema catalog refresh (including the ``prepare_connection`` warm-up this triggers for each database touched for the first time), saved queries, column type config and the ``startup`` hook. Runs once per process, before any request exists, so without this span every child it creates would be its own orphan root trace. A connection warmed later - lazily, the first time a *request* touches a new database or thread - nests under that request's own span instead, not under this one, since this span has already ended by then. + + No attributes. + +.. [[[end]]] + +.. _internals_telemetry_privacy: + +Privacy and safety +------------------ + +Spans leave your infrastructure whenever you configure an exporter, so what goes into them is a security decision. Datasette's rules are: + +- **SQL text is truncated to 2048 characters.** On a public instance the SQL is supplied by visitors and is unbounded in length, so ``db.query.text`` is cut off - with a ``…[truncated]`` marker - rather than allowed to set the size of a span. +- **SQL parameter values are never recorded.** Only ``datasette.param_count``, a count. Parameter values are the part of a query most likely to hold something sensitive, and separating them from the SQL is the reason bound parameters exist. +- **No actor identifiers are recorded.** No actor ID, no actor JSON, no client IP address. Nothing on a span identifies who made the request. +- **Table names come only from an explicit** ``table=`` **argument.** ``db.collection.name`` is set by callers that already know which table they are working with, and is never derived from the SQL. Deriving it would mean parsing, and on an instance where visitors can create tables the set of possible values has no ceiling. + +The SQL itself, though, *is* recorded, and on a public instance that means anything a visitor types into the query editor or passes as ``?sql=`` will be exported along with the span. That is the trade-off tracing a query engine makes. + +.. _internals_telemetry_limitations: + +Known limitations +----------------- + +- **Datasette does not create a span for the HTTP request itself.** Every span listed above is therefore a root span unless something above Datasette - an ASGI instrumentation layer, or the web framework embedding it - has already started one for the request, in which case Datasette's spans nest underneath it correctly. +- **Two plugin hooks run outside the** ``datasette.startup`` **span.** ``register_output_renderer`` is dispatched from ``Datasette.__init__()`` and ``asgi_wrapper`` from ``Datasette.app()``, both of which happen before ``invoke_startup()``. Datasette itself queries no database in either, so a default install emits nothing there - but a plugin that does will produce a root trace. Covering these would mean holding a span open across object construction, which is worse than the orphan. +- ``db.operation.name`` **reports** ``WITH`` **for a statement that opens with a common table expression**, rather than the operation inside it, and a substantial share of Datasette's own reads take that form. The attribute is a leading-keyword match against a fixed allowlist, deliberately not a parse. +- **Spans emitted before a provider is installed are not recorded.** If you are embedding Datasette in a host application, install your ``TracerProvider`` before serving traffic. This is ordinary OpenTelemetry behaviour rather than anything Datasette controls; nothing is permanently affected, those particular spans are simply dropped. + .. _internals_csrf: CSRF protection diff --git a/docs/telemetry_doc.py b/docs/telemetry_doc.py new file mode 100644 index 00000000..3551ef0e --- /dev/null +++ b/docs/telemetry_doc.py @@ -0,0 +1,37 @@ +""" +Render the span reference in ``internals.rst`` from +``datasette/telemetry_registry.py``. + +Driven by cog, and ``cog --check docs/*.rst`` runs in CI - so adding a span +without documenting it, or documenting one that no longer exists, is a build +failure rather than something a reader discovers later. +""" + + +def _attribute_lines(cog, attributes): + if not attributes: + cog.out(" No attributes.\n\n") + return + cog.out(" Attributes:\n\n") + for attribute in attributes: + suffix = " *(optional)*" if attribute.optional else "" + cog.out(f" - ``{attribute}``{suffix} - {attribute.description}\n") + cog.out("\n") + + +def spans(cog): + from opentelemetry.trace import SpanKind + + from datasette.telemetry_registry import SPANS + + cog.out("\n") + for span in SPANS: + title = f"{span}*" if span.prefix else str(span) + cog.out(f"``{title}``\n") + cog.out(f" {span.description}\n\n") + # INTERNAL is the default and the overwhelming majority of spans - + # printing it on every one would be noise. Only the exceptional case, + # a real database call, is worth calling out. + if span.kind != SpanKind.INTERNAL: + cog.out(f" Kind: ``{span.kind.name}``.\n\n") + _attribute_lines(cog, span.attributes) diff --git a/pyproject.toml b/pyproject.toml index e658955f..9dd231d7 100644 --- a/pyproject.toml +++ b/pyproject.toml @@ -40,6 +40,7 @@ dependencies = [ "setuptools", "pip", "pydantic>=2", + "opentelemetry-api>=1.37", ] [project.urls] @@ -70,6 +71,7 @@ dev = [ "cogapp>=3.3.0", "multipart-form-data-conformance==0.1a0", "ruff>=0.16.0", + "opentelemetry-sdk>=1.37", # docs "Sphinx==7.4.7", "furo==2025.9.25", diff --git a/tests/conftest.py b/tests/conftest.py index 12dce417..b01f111d 100644 --- a/tests/conftest.py +++ b/tests/conftest.py @@ -58,6 +58,62 @@ def find_free_port(): return sock.getsockname()[1] +_otel_span_exporter = None + + +@pytest.fixture(scope="session", autouse=True) +def _otel_provider(): + """ + Install a real OTel SDK TracerProvider + InMemorySpanExporter exactly + once, before any span is ever created in this process. + + This has to be session-scoped and autouse because + `opentelemetry.trace.set_tracer_provider()` is effectively + once-per-process: a second call logs a warning and is ignored. So the + install must happen exactly once, before anything asserts on spans. + + `datasette.telemetry.tracer` is a module-level `ProxyTracer`. Once a + provider exists, the first span it starts resolves a concrete tracer + and caches it permanently. It does *not* cache the no-op tracer, so + any span started before this fixture runs is merely lost rather than + poisoning the tracer for the rest of the process. If the SDK isn't + installed, do nothing: core spans stay no-op `NonRecordingSpan`s and + the rest of the suite is unaffected. + """ + global _otel_span_exporter + try: + from opentelemetry import trace as otel_trace + from opentelemetry.sdk.trace import TracerProvider + from opentelemetry.sdk.trace.export import SimpleSpanProcessor + from opentelemetry.sdk.trace.export.in_memory_span_exporter import ( + InMemorySpanExporter, + ) + except ImportError: + return + exporter = InMemorySpanExporter() + provider = TracerProvider() + # SimpleSpanProcessor exports synchronously on span end - no background + # batching thread, so assertions immediately after a request never race. + provider.add_span_processor(SimpleSpanProcessor(exporter)) + otel_trace.set_tracer_provider(provider) + _otel_span_exporter = exporter + + +@pytest.fixture +def otel_spans(): + """ + Function-scoped access to the finished-spans exporter: clears any spans + left over from previous tests, then yields the exporter so a test can + call `.get_finished_spans()` after making requests. Skips (rather than + fails) if the OTel SDK is not installed. + """ + pytest.importorskip("opentelemetry.sdk") + if _otel_span_exporter is None: + pytest.skip("OpenTelemetry SDK provider was not installed") + _otel_span_exporter.clear() + yield _otel_span_exporter + + @pytest.fixture def bare_ds(): """ @@ -168,6 +224,12 @@ def pytest_collection_modifyitems(config, items): move_to_front(items, "test_spatialite_error_if_attempt_to_open_spatialite") move_to_front(items, "test_package") move_to_front(items, "test_package_with_port") + # Same reason: this one shells out to a fresh interpreter. Late in a serial + # run the pytest process holds enough threads that the fork half of + # subprocess' fork+exec crashes the interpreter on macOS/CPython 3.13 + # (SIGSEGV/SIGBUS inside _execute_child). Reproduces with any subprocess + # call placed there, on an unmodified tree - running it first avoids it. + move_to_front(items, "test_datasette_package_never_imports_the_sdk") def move_to_front(items, test_name): diff --git a/tests/test_internals_database.py b/tests/test_internals_database.py index b1093b1c..ce0d7a53 100644 --- a/tests/test_internals_database.py +++ b/tests/test_internals_database.py @@ -3,11 +3,13 @@ Tests for the datasette.database.Database class """ import asyncio +import threading import uuid from types import SimpleNamespace import pytest import sqlite_utils +from opentelemetry import context as otel_context_api from datasette.app import Datasette from datasette.database import ( @@ -1223,3 +1225,110 @@ async def test_database_close_is_idempotent(tmpdir): # Second call should be a no-op, not raise db.close() ds._internal_database.close() + + +_CONTEXT_LEAK_MARKER_KEY = "otel-context-leak-marker" + + +@pytest.mark.asyncio +@pytest.mark.parametrize("num_sql_threads", (0, 1)) +async def test_write_thread_context_is_detached_between_tasks( + tmp_path, monkeypatch, num_sql_threads +): + """ + The write thread attaches each task's otel Context and must detach it + again before picking up the next task. The thread is persistent and + shared, so a leaked token would grow that thread's context stack for the + rest of the process - and a *wrong*-token detach only logs a warning + rather than raising, so "does it throw" cannot catch either mistake. + + Two things are asserted, because neither alone is sufficient: + + 1. Each task observes the context value that was current on the event + loop when it was queued. This is what fails if the Context is not + carried on WriteTask, or is never attached. It does *not* catch a + missing detach: attach() replaces the current Context wholesale, so a + leftover one from a previous task is simply overwritten. + 2. The write thread's attach depth is identical at the same point in + every task. This is what fails if detach is missing - the stack grows + by one per task - and it holds across a task that raises, because the + detach lives in a `finally`. + + An otel context value is used rather than a plain contextvars.ContextVar: + a plain var set on the event loop never crosses into the write thread, so + the probe would read None every time and the test could not fail. + """ + name = f"context_leak_test_{num_sql_threads}" + db_path = tmp_path / f"{name}.db" + sqlite3.connect(db_path).close() + ds = Datasette([str(db_path)], settings={"num_sql_threads": num_sql_threads}) + db = ds.get_database(name) + await db.execute_write("create table t (id integer primary key)") + + write_thread_name = f"_execute_writes for database {name}" + depth = {"value": 0} + real_attach = otel_context_api.attach + real_detach = otel_context_api.detach + + def counting_attach(context): + token = real_attach(context) + if threading.current_thread().name == write_thread_name: + depth["value"] += 1 + return token + + def counting_detach(token): + real_detach(token) + if threading.current_thread().name == write_thread_name: + depth["value"] -= 1 + + # Patched on the opentelemetry.context module itself, which is what both + # database.py and opentelemetry.trace.use_span() look the functions up on. + monkeypatch.setattr(otel_context_api, "attach", counting_attach) + monkeypatch.setattr(otel_context_api, "detach", counting_detach) + + seen_markers = [] + seen_depths = [] + + def probe(conn): + seen_markers.append(otel_context_api.get_value(_CONTEXT_LEAK_MARKER_KEY)) + seen_depths.append(depth["value"]) + + def failing_probe(conn): + probe(conn) + # Exercises the write thread's exception path: the detach still has + # to happen, which is why it lives in a `finally`. + raise ValueError("deliberate failure inside a write task") + + try: + for i in range(5): + ctx = otel_context_api.set_value(_CONTEXT_LEAK_MARKER_KEY, f"marker-{i}") + token = real_attach(ctx) + try: + if i == 2: + with pytest.raises(ValueError): + await db.execute_write_fn(failing_probe) + else: + await db.execute_write_fn(probe) + finally: + real_detach(token) + + # Sanity check: no marker is active in *this* (event loop) context + # right now, so the final probe is a fair test of the write thread's + # own state rather than something this test forgot to clean up. + assert otel_context_api.get_value(_CONTEXT_LEAK_MARKER_KEY) is None + await db.execute_write_fn(probe) + finally: + db.close() + + assert seen_markers == [ + "marker-0", + "marker-1", + "marker-2", + "marker-3", + "marker-4", + None, + ] + assert len(set(seen_depths)) == 1, ( + f"write thread context stack grew across tasks: {seen_depths} - " + "a token was attached without being detached" + ) diff --git a/tests/test_telemetry.py b/tests/test_telemetry.py new file mode 100644 index 00000000..0022883a --- /dev/null +++ b/tests/test_telemetry.py @@ -0,0 +1,1015 @@ +import json +import sqlite3 +import subprocess +import sys +import threading +import time + +import pytest +import sqlite_utils +from opentelemetry import context as otel_context_api +from opentelemetry import trace as otel_trace +from opentelemetry.trace import SpanKind, StatusCode + +from datasette.app import Datasette +from datasette.database import Database, QueryInterrupted +from datasette.telemetry import ( + MAX_SQL_LENGTH, + SCHEMA_URL, + sql_attribute, + sql_operation_name, + tracer, +) +from datasette.version import __version__ + +SECRET_PARAM_VALUE = "SUPER_SECRET_PARAM_VALUE_XYZ_123" + +INVALID_SQL = "select this_is_not_valid_sql from nowhere" + +# Bounded so a broken time limit fails the test instead of hanging it, but far +# too long to finish inside any of the millisecond budgets used below. +SLOW_SQL = """ +with recursive counter(x) as ( + select 1 union all select x + 1 from counter where x < 50000000 +) +select max(x) from counter +""" + + +def _db_query_spans(otel_spans): + return [span for span in otel_spans.get_finished_spans() if span.name == "db.query"] + + +def _spans_for_namespace(otel_spans, namespace): + """ + db.query spans belonging to one database. + + Datasette queries its internal catalog constantly - including while a + Datasette instance is being constructed - so a test that just grabbed + every db.query span would be reading someone else's traffic. + """ + return [ + span + for span in _db_query_spans(otel_spans) + if span.attributes["db.namespace"] == namespace + ] + + +def _children_named(otel_spans, name, parent_span_context): + """ + Finished spans called `name` whose parent really is `parent_span_context`. + + Parentage is matched on span id, not on "a span with this name exists" - + a span can exist and still be an unparented root if a thread boundary + dropped the otel context, which is the exact failure these tests exist + to catch. + """ + return [ + span + for span in otel_spans.get_finished_spans() + if span.name == name + and span.parent is not None + and span.parent.span_id == parent_span_context.span_id + and span.parent.trace_id == parent_span_context.trace_id + and span.context.trace_id == parent_span_context.trace_id + ] + + +def _descends_from(span, ancestor_span_context, by_span_id): + """ + True if `span` reaches `ancestor_span_context` by walking parent links. + + Walks real span ids rather than trusting a shared trace id: a span can + carry the right trace id and still hang off the wrong parent. + """ + seen = set() + current = span + while current.parent is not None: + if current.parent.span_id == ancestor_span_context.span_id: + return current.parent.trace_id == ancestor_span_context.trace_id + if current.parent.span_id in seen: + return False + seen.add(current.parent.span_id) + current = by_span_id.get(current.parent.span_id) + if current is None: + return False + return False + + +def _all_attribute_values(otel_spans): + "Every attribute value across every finished span, for the 'no leaked param values' test." + values = [] + for span in otel_spans.get_finished_spans(): + values.extend((span.attributes or {}).values()) + for event in span.events: + values.extend((event.attributes or {}).values()) + return values + + +def test_datasette_package_never_imports_the_sdk(): + """ + Core depends on opentelemetry-api only. The SDK is a test dependency. + + Checked by importing datasette in a fresh process and inspecting + sys.modules, rather than by grepping, so a lazy `import + opentelemetry.sdk` inside a function body cannot slip past. + + conftest.py's pytest_collection_modifyitems() moves this test to the + front of the run by name - if you rename it, rename it there too. + """ + code = ( + "import datasette.app, datasette.database, datasette.telemetry, sys; " + "print([m for m in sys.modules if m.startswith('opentelemetry.sdk')])" + ) + result = subprocess.run( + [sys.executable, "-c", code], capture_output=True, text=True, check=True + ) + assert ( + result.stdout.strip() == "[]" + ), f"datasette imported the OpenTelemetry SDK: {result.stdout.strip()}" + + +@pytest.mark.asyncio +async def test_db_query_span_basic_attributes(ds_client, otel_spans): + response = await ds_client.get("/fixtures/-/query.json?sql=select+1") + assert response.status_code == 200 + + spans = _db_query_spans(otel_spans) + assert spans, "expected at least one db.query span" + span = spans[-1] + + assert span.attributes["db.system"] == "sqlite" + assert span.attributes["db.namespace"] == "fixtures" + assert span.attributes["db.query.text"] == "select 1" + assert span.attributes["datasette.rows_returned"] == 1 + assert span.attributes["datasette.truncated"] is False + assert isinstance(span.attributes["datasette.time_limit_ms"], int) + assert span.status.status_code == StatusCode.UNSET + + +@pytest.mark.asyncio +async def test_facetable_request_produces_db_query_spans(ds_client, otel_spans): + response = await ds_client.get("/fixtures/facetable.json") + assert response.status_code == 200 + + spans = _db_query_spans(otel_spans) + assert spans, "expected at least one db.query span" + assert all(span.attributes["db.system"] == "sqlite" for span in spans) + assert all(span.attributes["db.query.text"] for span in spans) + # Rendering the page also queries the internal database, so only some of + # these spans belong to "fixtures". + assert any(span.attributes["db.namespace"] == "fixtures" for span in spans) + + +def test_sql_attribute_truncates_at_2048(): + short_sql = "select 1" + assert sql_attribute(short_sql) == "select 1" + # Whitespace is stripped, so the same query logged twice with different + # surrounding whitespace produces one attribute value, not two. + assert sql_attribute(" select 1\n") == "select 1" + + long_sql = "select 1 -- " + ("x" * 3000) + truncated = sql_attribute(long_sql) + assert len(truncated) == MAX_SQL_LENGTH + len("…[truncated]") + assert truncated.startswith("select 1 -- ") + assert truncated.endswith("…[truncated]") + + +@pytest.mark.asyncio +async def test_db_query_text_is_truncated_in_real_span(ds_client, otel_spans): + # A long trailing SQL comment keeps the query valid and executable while + # pushing db.query.text well past the 2048 char cap. + long_sql = "select 1 -- " + ("x" * 3000) + response = await ds_client.get("/fixtures/-/query.json", params={"sql": long_sql}) + assert response.status_code == 200 + + spans = _db_query_spans(otel_spans) + assert spans + assert any(len(span.attributes["db.query.text"]) > 100 for span in spans), ( + "expected the long query to reach a span - otherwise this test would " + "pass even if truncation were never applied" + ) + for span in spans: + recorded = span.attributes["db.query.text"] + assert len(recorded) <= MAX_SQL_LENGTH + len("…[truncated]") + + +@pytest.mark.asyncio +async def test_no_span_attribute_ever_contains_a_parameter_value(ds_client, otel_spans): + response = await ds_client.get( + "/fixtures/-/query.json", + params={"sql": "select :secret", "secret": SECRET_PARAM_VALUE}, + ) + assert response.status_code == 200 + # Sanity check the value really did flow through as a bound parameter, + # not inlined into the SQL text, otherwise this test would be vacuous. + assert SECRET_PARAM_VALUE in json.dumps(response.json()) + + for value in _all_attribute_values(otel_spans): + if isinstance(value, str): + assert SECRET_PARAM_VALUE not in value + elif isinstance(value, (list, tuple)): + for item in value: + if isinstance(item, str): + assert SECRET_PARAM_VALUE not in item + + spans = _db_query_spans(otel_spans) + assert spans + span = spans[-1] + assert "select :secret" in span.attributes["db.query.text"] + assert span.attributes.get("datasette.param_count") == 1 + + +@pytest.mark.asyncio +async def test_query_interrupted_sets_error_status(otel_spans): + """ + A query that runs out the instance-wide sql_time_limit_ms is an error. + + This used to force the timeout with `?_timelimit=5`, but a caller-supplied + budget shorter than the instance limit is now the signal that the timeout + was expected - see test_expected_timeout_is_not_a_span_error - so the + timeout has to come from the setting for this to still test what it was + written to test. + """ + ds = Datasette(memory=True, settings={"sql_time_limit_ms": 20}) + db = ds.add_memory_database("t09_instance_limit_timeout") + with pytest.raises(QueryInterrupted): + await db.execute(SLOW_SQL) + + spans = _spans_for_namespace(otel_spans, "t09_instance_limit_timeout") + assert spans + span = spans[-1] + assert span.status.status_code == StatusCode.ERROR + assert span.attributes["datasette.interrupted"] is True + assert span.events + assert all(event.name == "exception" for event in span.events) + + +async def _expected_timeout_count_span(otel_spans, database_name): + """ + Drive the real table_counts() path into a timeout; return its db.query span. + + table_counts() is where the headline instance of this lives: the homepage + counts every table under a 10ms budget and stores None for any table that + does not finish in time. Before this was fixed, a two-table database + produced four ERROR spans - two db.query and two db.query.execute - on + every single homepage hit. + """ + db = Datasette(memory=True).add_memory_database(database_name) + await db.execute_write("create table big (id integer primary key, t text)") + await db.execute_write_many( + "insert into big (t) values (?)", [["x" * 50] for _ in range(11000)] + ) + # count_limit caps the scan at 10001 rows, and below 20ms sqlite_timelimit() + # runs its progress handler on every VM instruction, so 1ms is not a close + # call - a scan of that size takes single-digit milliseconds at best. + counts = await db.table_counts(1) + assert counts == { + "big": None + }, "the count did not actually time out, so the rest of this test is vacuous" + + spans = [ + span + for span in _spans_for_namespace(otel_spans, database_name) + if "count(*)" in span.attributes["db.query.text"] + ] + assert len(spans) == 1 + return spans[0] + + +@pytest.mark.asyncio +async def test_expected_timeout_is_not_a_span_error(otel_spans): + span = await _expected_timeout_count_span(otel_spans, "t09_expected_timeout") + # The useful signal survives; only the red status goes away. + assert span.attributes["datasette.interrupted"] is True + assert span.status.status_code != StatusCode.ERROR + assert not [event for event in span.events if event.name == "exception"] + + +@pytest.mark.asyncio +async def test_expected_timeout_does_not_error_the_inner_execute_span(otel_spans): + """ + The same fix has to reach db.query.execute, which sets its own status. + + Half of the original bug lived here: the inner span passed + set_status_on_exception=log_sql_errors, and table_counts() leaves + log_sql_errors at its True default, so it went ERROR too. + """ + span = await _expected_timeout_count_span(otel_spans, "t09_expected_timeout_inner") + children = _children_named(otel_spans, "db.query.execute", span.context) + assert len(children) == 1 + child = children[0] + assert child.status.status_code != StatusCode.ERROR + assert not [event for event in child.events if event.name == "exception"] + + +@pytest.mark.asyncio +async def test_unexpected_timeout_is_still_a_span_error(otel_spans): + """ + A custom_time_limit *above* sql_time_limit_ms is not a short budget. + + This is the half of the rule that stops the fix collapsing into "never + report timeouts": the caller asked for 5 seconds, the instance overruled it + at 20ms, and nobody expected that. + """ + ds = Datasette(memory=True, settings={"sql_time_limit_ms": 20}) + db = ds.add_memory_database("t09_custom_limit_ignored") + with pytest.raises(QueryInterrupted): + await db.execute(SLOW_SQL, custom_time_limit=5000) + + spans = _spans_for_namespace(otel_spans, "t09_custom_limit_ignored") + assert spans + span = spans[-1] + # Proves the caller's larger budget really was discarded - otherwise this + # would be asserting on a query that ran under a 5s limit. + assert span.attributes["datasette.time_limit_ms"] == 20 + assert span.attributes["datasette.interrupted"] is True + assert span.status.status_code == StatusCode.ERROR + assert any(event.name == "exception" for event in span.events) + + children = _children_named(otel_spans, "db.query.execute", span.context) + assert len(children) == 1 + assert children[0].status.status_code == StatusCode.ERROR + + +@pytest.mark.asyncio +async def test_unsuppressed_sql_error_is_a_span_error(ds_client, otel_spans): + db = ds_client.ds.get_database("fixtures") + with pytest.raises(sqlite3.OperationalError): + await db.execute(INVALID_SQL) + + spans = _db_query_spans(otel_spans) + assert spans + span = spans[-1] + assert span.status.status_code == StatusCode.ERROR + assert any(event.name == "exception" for event in span.events) + assert "datasette.sql_error_suppressed" not in span.attributes + + +@pytest.mark.asyncio +async def test_suppressed_sql_error_is_not_a_span_error(ds_client, otel_spans): + """ + log_sql_errors=False means the caller is probing and expects failures. + + Facet suggestion runs `json_type(column)` against every column precisely + to discover which ones raise, so marking those spans as errors would put + two red spans per text column on every table page - burying real failures + and tripping any alerting keyed on span status. + """ + db = ds_client.ds.get_database("fixtures") + with pytest.raises(sqlite3.OperationalError): + await db.execute(INVALID_SQL, log_sql_errors=False) + + spans = _db_query_spans(otel_spans) + assert spans + span = spans[-1] + assert span.status.status_code == StatusCode.UNSET + assert span.attributes["datasette.sql_error_suppressed"] is True + assert not [event for event in span.events if event.name == "exception"] + + +@pytest.mark.asyncio +async def test_execute_write_produces_db_query_span(otel_spans): + # Named in-memory databases are shared-cache, so every test in this file + # needs its own name or the second `create table` hits an existing table. + db = Datasette(memory=True).add_memory_database("t03_write_span") + await db.execute_write("create table docs (id integer primary key, name text)") + await db.execute_write("insert into docs (id, name) values (?, ?)", [1, "one"]) + + spans = _spans_for_namespace(otel_spans, "t03_write_span") + assert spans, "expected db.query spans from execute_write()" + span = spans[-1] + + assert span.attributes["db.system"] == "sqlite" + assert span.attributes["db.namespace"] == "t03_write_span" + assert span.attributes["db.query.text"] == ( + "insert into docs (id, name) values (?, ?)" + ) + assert span.attributes["datasette.param_count"] == 2 + + +@pytest.mark.asyncio +async def test_execute_write_script_sets_executescript_attribute(otel_spans): + db = Datasette(memory=True).add_memory_database("t03_write_script_span") + await db.execute_write_script( + "create table docs (id integer primary key);\n" + "insert into docs (id) values (1);" + ) + + spans = _spans_for_namespace(otel_spans, "t03_write_script_span") + assert spans, "expected a db.query span from execute_write_script()" + span = spans[-1] + + assert span.attributes["db.system"] == "sqlite" + assert span.attributes["datasette.executescript"] is True + assert "insert into docs" in span.attributes["db.query.text"] + + +@pytest.mark.asyncio +async def test_execute_write_many_records_param_sets_not_rows_returned(otel_spans): + db = Datasette(memory=True).add_memory_database("t03_write_many_span") + await db.execute_write("create table docs (id integer primary key)") + await db.execute_write_many( + "insert into docs (id) values (?)", [[i] for i in range(1, 6)] + ) + + spans = _spans_for_namespace(otel_spans, "t03_write_many_span") + many_spans = [ + span for span in spans if span.attributes.get("datasette.executemany") is True + ] + assert len(many_spans) == 1 + span = many_spans[0] + + assert span.attributes["datasette.param_sets"] == 5 + # executemany() consumes parameter sets and returns no rows at all, so + # calling this a row count would be a lie. Asserted explicitly because the + # attribute really was named datasette.rows_returned at one point. + assert "datasette.rows_returned" not in span.attributes + + +# --- Context propagation across thread boundaries -------------------------- +# +# Every assertion below checks parentage (child.parent.span_id == +# expected_parent.span_id, in the same trace), not merely that spans exist. +# Spans can exist and still be wrongly parented - or be unparented roots - if +# a thread boundary drops the otel context, which is exactly the failure mode +# these tests exist to prevent. + + +@pytest.mark.asyncio +async def test_db_query_execute_parents_to_db_query(ds_client, otel_spans): + # execute_fn()'s executor.submit() is thread boundary #1. The + # db.query.execute span is created inside the worker thread; without the + # copy_context() propagation it comes back as an unparented root span + # rather than a child of db.query. + response = await ds_client.get("/fixtures/-/query.json?sql=select+1") + assert response.status_code == 200 + + query_spans = [ + span + for span in _spans_for_namespace(otel_spans, "fixtures") + if span.attributes["db.query.text"] == "select 1" + ] + assert query_spans, "expected a db.query span for 'select 1'" + query_span = query_spans[-1] + + assert [ + span + for span in otel_spans.get_finished_spans() + if span.name == "db.query.execute" + ], "expected at least one db.query.execute span" + children = _children_named(otel_spans, "db.query.execute", query_span.context) + assert len(children) == 1, "expected exactly one db.query.execute child of db.query" + # The execute span is strictly contained by the round-trip span, and the + # gap between the two is the thread-pool wait. + assert query_span.start_time <= children[0].start_time + assert children[0].end_time <= query_span.end_time + + +@pytest.mark.asyncio +async def test_immutable_database_propagates_context(tmp_path, otel_spans): + # Thread boundary #3, the easy one to miss: immutable databases route + # execute_isolated_fn() through loop.run_in_executor() directly rather + # than through the write thread. A span created inside that worker must + # still parent to whatever was current when execute_isolated_fn() was + # awaited, or every immutable-database operation emits orphan roots. + db_path = tmp_path / "t04_immutable.db" + sqlite_utils.Database(str(db_path))["t"].insert({"id": 1}, pk="id") + + ds = Datasette() + db = Database(ds, path=str(db_path), is_mutable=False) + ds.add_database(db, name="t04_immutable") + + def fn(conn): + with tracer.start_as_current_span("t04-child-in-isolated-worker"): + pass + + try: + with tracer.start_as_current_span("t04-parent-on-event-loop") as parent: + parent_context = parent.get_span_context() + await db.execute_isolated_fn(fn) + finally: + ds.remove_database("t04_immutable") + + assert [ + span + for span in otel_spans.get_finished_spans() + if span.name == "t04-child-in-isolated-worker" + ], "expected a span created inside execute_isolated_fn's worker thread" + children = _children_named( + otel_spans, "t04-child-in-isolated-worker", parent_context + ) + assert len(children) == 1 + + +@pytest.mark.asyncio +async def test_write_spans_parent_to_db_query(otel_spans): + # Thread boundary #2: WriteTask -> queue.Queue -> the write thread. + # db.write.queue_wait and db.write.execute are both direct children of + # the db.query span that was current on the event loop at enqueue time, + # so they are siblings rather than nested inside one another. + db = Datasette(memory=True).add_memory_database("t04_write_spans") + await db.execute_write("create table docs (id integer primary key)") + + query_spans = _spans_for_namespace(otel_spans, "t04_write_spans") + assert query_spans, "expected a db.query span from execute_write()" + query_span = query_spans[-1] + + queue_wait_children = _children_named( + otel_spans, "db.write.queue_wait", query_span.context + ) + execute_children = _children_named( + otel_spans, "db.write.execute", query_span.context + ) + assert len(queue_wait_children) == 1 + assert len(execute_children) == 1 + + execute_span = execute_children[0] + assert execute_span.attributes["datasette.isolated_connection"] is False + assert execute_span.attributes["datasette.transaction"] is True + # Siblings, not parent/child: the queue wait is over by the time the + # write begins. + assert queue_wait_children[0].end_time <= execute_span.start_time + + +@pytest.mark.asyncio +async def test_write_queue_wait_duration_reflects_real_wait(otel_spans): + # db.write.queue_wait is built from explicit start/end timestamps - + # task.enqueued_at_ns, captured on the event loop, through to the moment + # the write thread dequeued it. If it were a plain `with` block on the + # write thread it would instead measure the microseconds spent building + # the span object, and this assertion would fail. + ds = Datasette(memory=True) + db = ds.add_memory_database("t04_queue_wait") + await db.execute_write("create table docs (id integer primary key)") + + def slow_write(conn): + time.sleep(0.1) + + # Queue a deliberately slow write without waiting for it, then queue a + # second write immediately behind it: the second task sits in the queue + # for roughly the duration of the first. + _, slow_future = await db._send_to_write_thread(slow_write, block=False) + await db.execute_write("insert into docs (id) values (1)") + await slow_future + + query_spans = [ + span + for span in _spans_for_namespace(otel_spans, "t04_queue_wait") + if span.attributes["db.query.text"] == "insert into docs (id) values (1)" + ] + assert query_spans, "expected a db.query span for the queued-behind insert" + queue_wait_children = _children_named( + otel_spans, "db.write.queue_wait", query_spans[-1].context + ) + assert len(queue_wait_children) == 1 + duration_ns = queue_wait_children[0].end_time - queue_wait_children[0].start_time + # The slow write sleeps 100ms; anything above 10ms is far beyond the + # microseconds a mis-timestamped span would report. + assert duration_ns > 10_000_000, f"queue wait was only {duration_ns}ns" + + +async def _write_spans_from_one_enqueue(otel_spans, name, block): + """ + Run exactly one write through the write thread from inside a span of our + own, and return (enqueueing span context, {span name: span}). + + `_send_to_write_thread` is called directly rather than `execute_write()` + because `execute_write()` opens its own db.query span, which would then + be the span current at enqueue time - so the parent/link would point at + that span rather than at the one this test controls. + + The exporter is cleared immediately before the enqueue so the write spans + collected here can only have come from this one write. + """ + db = Datasette(memory=True).add_memory_database(name) + await db.execute_write("create table docs (id integer primary key)") + + def insert(conn): + conn.execute("insert into docs (id) values (1)") + + otel_spans.clear() + with tracer.start_as_current_span("enqueueing-span") as enqueuer: + enqueuer_context = enqueuer.get_span_context() + queued = await db._send_to_write_thread(insert, block=block) + if not block: + # The point of block=False is that the write happens after the + # caller has returned and the enqueueing span above has closed. + # Awaiting the reply future outside that `with` waits for the write + # thread deterministically - it is resolved only after both write + # spans have ended and been exported. + _, reply_future = queued + await reply_future + + spans = {} + for span in otel_spans.get_finished_spans(): + if span.name in ("db.write.queue_wait", "db.write.execute"): + assert span.name not in spans, f"more than one {span.name} span" + spans[span.name] = span + assert set(spans) == {"db.write.queue_wait", "db.write.execute"} + return enqueuer_context, spans + + +@pytest.mark.asyncio +async def test_blocking_write_spans_still_parent_normally(otel_spans): + # Regression guard for ticket 07: block=True genuinely has containment - + # the caller awaits the reply future - so those spans must keep parenting + # to the enqueueing span, and must not grow links. + enqueuer_context, spans = await _write_spans_from_one_enqueue( + otel_spans, "t07_blocking_write", block=True + ) + for name, span in spans.items(): + assert span.parent is not None, f"{name} lost its parent" + assert span.parent.span_id == enqueuer_context.span_id, name + assert span.parent.trace_id == enqueuer_context.trace_id, name + assert span.context.trace_id == enqueuer_context.trace_id, name + assert span.links == (), f"{name} should be parented, not linked" + + +@pytest.mark.asyncio +async def test_nonblocking_write_spans_are_roots_with_a_link(otel_spans): + # block=False returns before the write runs, so the enqueueing span has + # already ended (and exported) by the time these spans start. Parenting + # them to it would draw a child outliving its closed parent, so they are + # roots in their own traces, linked back to the span that caused them. + enqueuer_context, spans = await _write_spans_from_one_enqueue( + otel_spans, "t07_nonblocking_write", block=False + ) + assert enqueuer_context.is_valid, "test's own enqueueing span was not recorded" + for name, span in spans.items(): + assert span.parent is None, f"{name} is still parented" + # A link does not join the linked trace: each of these is its own + # root trace, which is the correct shape and not a workaround. + assert span.context.trace_id != enqueuer_context.trace_id, name + assert len(span.links) == 1, f"{name} has links {span.links}" + link_context = span.links[0].context + assert link_context.trace_id == enqueuer_context.trace_id, name + assert link_context.span_id == enqueuer_context.span_id, name + # The two write spans are independent roots, not nested in one another. + assert ( + spans["db.write.queue_wait"].context.trace_id + != spans["db.write.execute"].context.trace_id + ) + + +@pytest.mark.asyncio +async def test_nonblocking_write_link_has_no_attributes(otel_spans): + # There is only one kind of link here, so a relationship-name attribute + # would be a constant conveying nothing the link's existence does not. + _, spans = await _write_spans_from_one_enqueue( + otel_spans, "t07_nonblocking_link_attrs", block=False + ) + for name, span in spans.items(): + assert len(span.links) == 1, name + assert dict(span.links[0].attributes or {}) == {}, name + + +@pytest.mark.asyncio +async def test_nonblocking_write_spans_ignore_the_write_threads_ambient_context( + otel_spans, +): + """ + block=False spans pass an explicit empty Context, not merely "no attach". + + Nothing is attached for a block=False task, but "nothing attached" is not + the same as "no ambient context": the write thread is persistent, and + anything running on it - a prepare_connection plugin hook, say - can + attach a context and never detach it. Without the explicit `context=` + these spans would silently parent to that leftover span instead of being + roots, and no other test here would notice, because in every other test + the write thread's ambient context happens to be empty. + + So this test leaks exactly such a context on the write thread, the way a + careless plugin would, and then checks the write spans are still roots. + """ + ds = Datasette(memory=True) + db = ds.add_memory_database("t07_ambient_write_thread") + write_thread_name = "_execute_writes for database t07_ambient_write_thread" + real_prepare_connection = ds._prepare_connection + leaked = {} + + def prepare_connection(conn, database): + if threading.current_thread().name == write_thread_name: + # Runs once, on the write thread, before any task is dequeued - + # and never detaches, which is the whole point. + span = tracer.start_span("leaked-write-thread-ambient-span") + leaked["span_id"] = span.get_span_context().span_id + otel_context_api.attach(otel_trace.set_span_in_context(span)) + return real_prepare_connection(conn, database) + + ds._prepare_connection = prepare_connection + try: + await db.execute_write("create table docs (id integer primary key)") + + def insert(conn): + conn.execute("insert into docs (id) values (1)") + + otel_spans.clear() + with tracer.start_as_current_span("enqueueing-span") as enqueuer: + enqueuer_context = enqueuer.get_span_context() + _, reply_future = await db._send_to_write_thread(insert, block=False) + await reply_future + finally: + ds._prepare_connection = real_prepare_connection + db.close() + + assert "span_id" in leaked, "the ambient context was never leaked - test is vacuous" + write_spans = [ + span + for span in otel_spans.get_finished_spans() + if span.name in ("db.write.queue_wait", "db.write.execute") + ] + assert len(write_spans) == 2 + for span in write_spans: + assert span.parent is None, ( + f"{span.name} parented to the write thread's leftover ambient " + "context instead of being a root" + ) + assert span.links[0].context.span_id == enqueuer_context.span_id + + +@pytest.mark.asyncio +async def test_suppressed_error_does_not_mark_execute_span(ds_client, otel_spans): + """ + The inner db.query.execute span must honour log_sql_errors too. + + It is created inside the worker thread, so without record_exception / + set_status_on_exception being passed through it would mark every facet + suggestion probe as failed even though the outer db.query span correctly + reports the failure as suppressed. + """ + db = ds_client.ds.get_database("fixtures") + with pytest.raises(sqlite3.OperationalError): + await db.execute(INVALID_SQL, log_sql_errors=False) + + execute_spans = [ + span + for span in otel_spans.get_finished_spans() + if span.name == "db.query.execute" + ] + assert execute_spans + span = execute_spans[-1] + assert span.status.status_code == StatusCode.UNSET + assert not [event for event in span.events if event.name == "exception"] + + +@pytest.mark.asyncio +async def test_invoke_startup_produces_one_trace_not_dozens_of_orphans(otel_spans): + """ + invoke_startup() runs with no request, so nothing it does has an ambient + span to nest under. Without datasette.startup every register_* hook, every + internal-catalog read and every catalog write becomes its own single-span + root trace - around twenty of them per fresh instance. + """ + ds = Datasette(memory=True) + # Named in-memory databases are shared-cache, so this needs its own name. + ds.add_memory_database("t05_startup_db") + # Constructing a Datasette already touches the internal catalog, and that + # work is genuinely outside startup. Clear so the assertions below describe + # invoke_startup() alone. + otel_spans.clear() + + # Deliberately no ambient span: this mirrors the ASGI lifespan path, where + # startup runs before any request exists. If something did wrap this call + # the "one root" assertion below would pass for the wrong reason. + assert ( + not otel_trace.get_current_span().get_span_context().is_valid + ), "this test must run with no ambient span" + + await ds.invoke_startup() + + spans = otel_spans.get_finished_spans() + assert len(spans) > 10, f"expected startup to emit many spans, got {len(spans)}" + + startup_spans = [span for span in spans if span.name == "datasette.startup"] + assert len(startup_spans) == 1 + startup = startup_spans[0] + assert startup.parent is None, "datasette.startup should be a root span" + + trace_ids = {span.context.trace_id for span in spans} + assert trace_ids == {startup.context.trace_id}, ( + f"startup produced {len(trace_ids)} distinct traces; every span it " + "causes should share the datasette.startup trace" + ) + + roots = [span for span in spans if span.parent is None] + assert [span.name for span in roots] == ["datasette.startup"] + + by_span_id = {span.context.span_id: span for span in spans} + + # The internal catalog reads are what made up the bulk of the orphans. + internal_queries = [ + span + for span in spans + if span.name == "db.query" and span.attributes["db.namespace"] == "__INTERNAL__" + ] + assert internal_queries, "expected internal-catalog db.query spans during startup" + assert all( + _descends_from(span, startup.context, by_span_id) for span in internal_queries + ) + + # ...and the catalog writes, which reach the span through the write thread, + # so they also prove the ticket-04 context capture survives startup. + write_spans = [span for span in spans if span.name.startswith("db.write.")] + assert write_spans, "expected db.write.* spans during startup" + assert all( + _descends_from(span, startup.context, by_span_id) for span in write_spans + ) + + +# --- Semantic conventions: span kind, scope, db.operation/collection ------- + + +@pytest.mark.asyncio +async def test_db_query_is_client_kind_and_children_are_internal(otel_spans): + """ + db.query is a database client span; Datasette's decomposition of it is not. + + Trace UIs key their database rendering off the span kind rather than off + db.system, so db.query has to be CLIENT. db.query.execute, + db.write.execute and db.write.queue_wait deliberately stay INTERNAL: they + are parts of one logical query rather than three separate database calls, + and queue_wait touches no database at all - marking them CLIENT would + make one query look like several to anything counting spans by kind. + """ + # Named in-memory databases are shared-cache, so this needs its own name. + db = Datasette(memory=True).add_memory_database("t06_span_kind") + # All four db.query entry points, so a missed `kind=` on any one of them + # fails here - plus the write path (db.write.queue_wait, + # db.write.execute) and the read path (db.query.execute) children. + await db.execute_write("create table docs (id integer primary key)") + await db.execute_write_many( + "insert into docs (id) values (?)", [[i] for i in range(1, 4)] + ) + await db.execute_write_script("insert into docs (id) values (99);") + await db.execute("select id from docs") + + query_spans = _spans_for_namespace(otel_spans, "t06_span_kind") + assert len(query_spans) == 4, "expected a db.query span per entry point" + for span in query_spans: + text = span.attributes["db.query.text"] + assert span.kind == SpanKind.CLIENT, f"db.query for {text!r} should be CLIENT" + + for name in ("db.query.execute", "db.write.execute", "db.write.queue_wait"): + children = [ + span for span in otel_spans.get_finished_spans() if span.name == name + ] + assert children, f"expected at least one {name} span" + for span in children: + assert span.kind == SpanKind.INTERNAL, f"{name} should be INTERNAL" + + +@pytest.mark.asyncio +async def test_instrumentation_scope_declares_version_and_schema_url( + ds_client, otel_spans +): + """ + Spans say which Datasette produced them and which semconv version their + attribute names follow. + + Before get_tracer() was given a version and a schema URL every exported + scope was name='datasette' version='' schema_url='', so nothing + downstream could tell which Datasette a span came from, or whether + `db.system` meant `db.system` or the post-1.30.0 `db.system.name`. + """ + response = await ds_client.get("/fixtures/-/query.json?sql=select+1") + assert response.status_code == 200 + + spans = _db_query_spans(otel_spans) + assert spans, "expected at least one db.query span" + scope = spans[-1].instrumentation_scope + + assert scope.name == "datasette" + assert scope.version == __version__ + # The literal URL, not the SCHEMA_URL constant: comparing the span + # against the same constant the instrumentation is built from would only + # catch a dropped argument, never a wrong value. Bumping this is a claim + # about the attribute names on the wire - see SCHEMA_URL in telemetry.py. + assert scope.schema_url == "https://opentelemetry.io/schemas/1.29.0" + assert SCHEMA_URL == "https://opentelemetry.io/schemas/1.29.0" + assert __version__, "the scope version must not be empty" + + +def test_db_operation_name_from_leading_keyword(): + assert sql_operation_name("select 1") == "SELECT" + assert sql_operation_name(" insert into x (a) values (1)") == "INSERT" + # A leading CTE reports WITH rather than the operation inside it. That is + # the documented limitation, not an accident - see sql_operation_name(). + assert sql_operation_name("with foo as (select 1) select * from foo") == "WITH" + # Unrecognised leading keyword: no attribute rather than a wrong one, and + # no unbounded value set derived from attacker-supplied SQL. + assert sql_operation_name("gibberish 1") is None + # Not a parser: a parenthesised SELECT and a leading comment both yield + # nothing rather than a guess. + assert sql_operation_name("(select 1) union select 2") is None + assert sql_operation_name("-- a comment\nselect 1") is None + assert sql_operation_name("") is None + + +@pytest.mark.asyncio +async def test_db_operation_name_on_real_span(ds_client, otel_spans): + response = await ds_client.get("/fixtures/-/query.json?sql=select+1") + assert response.status_code == 200 + + spans = [ + span + for span in _spans_for_namespace(otel_spans, "fixtures") + if span.attributes["db.query.text"] == "select 1" + ] + assert spans, "expected a db.query span for 'select 1'" + assert spans[-1].attributes["db.operation.name"] == "SELECT" + + +@pytest.mark.asyncio +async def test_execute_write_sets_db_operation_name(otel_spans): + db = Datasette(memory=True).add_memory_database("t06_write_operation") + await db.execute_write("create table docs (id integer primary key)") + await db.execute_write_many( + "insert into docs (id) values (?)", [[i] for i in range(1, 4)] + ) + + spans = _spans_for_namespace(otel_spans, "t06_write_operation") + by_operation = { + span.attributes["db.query.text"]: span.attributes.get("db.operation.name") + for span in spans + } + assert by_operation["create table docs (id integer primary key)"] == "CREATE" + assert by_operation["insert into docs (id) values (?)"] == "INSERT" + + +@pytest.mark.asyncio +async def test_execute_write_script_has_no_operation_name(otel_spans): + """ + executescript() runs several statements, so naming the operation after + the first one would be a lie. Semantic conventions say db.operation.name + should not be extracted from query text that can hold more than one + operation, so the attribute is absent entirely. + + The script deliberately starts with `create`, which *is* on the + allowlist - so this fails if the call site ever starts calling + sql_operation_name(). + """ + db = Datasette(memory=True).add_memory_database("t06_script_operation") + await db.execute_write_script( + "create table docs (id integer primary key);\n" + "insert into docs (id) values (1);" + ) + + spans = _spans_for_namespace(otel_spans, "t06_script_operation") + script_spans = [ + span for span in spans if span.attributes.get("datasette.executescript") is True + ] + assert len(script_spans) == 1 + assert "db.operation.name" not in script_spans[0].attributes + + +@pytest.mark.asyncio +async def test_db_collection_name_set_from_table_argument(ds_client, otel_spans): + db = ds_client.ds.get_database("fixtures") + await db.execute("select pk from facetable limit 1", table="facetable") + + spans = _spans_for_namespace(otel_spans, "fixtures") + assert spans + assert spans[-1].attributes["db.collection.name"] == "facetable" + + +@pytest.mark.asyncio +async def test_db_collection_name_absent_without_table_argument(ds_client, otel_spans): + """ + db.collection.name comes only from an explicit table= argument and is + never derived from the SQL. + + Deriving it would be a parse, and on an instance where anybody can create + a table the value set has no ceiling. Without this test the one above + would still pass if the table name were being read out of the query text. + """ + db = ds_client.ds.get_database("fixtures") + await db.execute("select pk from facetable limit 1") + + spans = _spans_for_namespace(otel_spans, "fixtures") + assert spans + span = spans[-1] + assert span.attributes["db.query.text"] == "select pk from facetable limit 1" + assert "db.collection.name" not in span.attributes + + +@pytest.mark.parametrize( + "path,table", + ( + ("/fixtures/facetable.json", "facetable"), + ("/fixtures/simple_primary_key/1.json", "simple_primary_key"), + ), +) +@pytest.mark.asyncio +async def test_table_and_row_pages_set_db_collection_name( + ds_client, otel_spans, path, table +): + "The table and row views know their table, so their queries carry it." + response = await ds_client.get(path) + assert response.status_code == 200 + + spans = _spans_for_namespace(otel_spans, "fixtures") + assert spans + assert any( + span.attributes.get("db.collection.name") == table for span in spans + ), f"expected a db.query span from {path} carrying db.collection.name" diff --git a/tests/test_telemetry_registry.py b/tests/test_telemetry_registry.py new file mode 100644 index 00000000..335eb946 --- /dev/null +++ b/tests/test_telemetry_registry.py @@ -0,0 +1,309 @@ +""" +Two-way conformance between `datasette/telemetry_registry.py` and what +Datasette actually emits. + +This is the test that makes the generated documentation trustworthy. cog +guarantees the docs match the registry; this guarantees the registry matches +the code. Without it, both could agree with each other and be wrong. + +It checks both directions, and the second one is the one nothing else catches: + +- **emitted but not registered** - instrumentation was added without + documenting it, so the reference page silently omits it. +- **registered but never emitted** - the reference page describes a span or + attribute that no longer exists, which is worse than omitting it, because a + reader will build a dashboard on it. + +Both of those directions compare the code against the registry. Neither can +catch a *rename*, because the call sites now take their names from the +registry - move `DB_NAMESPACE` to `"db.namespace2"` and code and registry +still agree with each other, while every existing dashboard breaks. So the +literal names live here too, spelled out, and are asserted against both the +registry and the wire. That is the one comparison in this file that is not +made against a value derived from the registry itself. +""" + +import itertools + +import pytest +import pytest_asyncio + +pytest.importorskip("opentelemetry.sdk") + +from datasette import telemetry_registry as reg +from datasette.app import Datasette +from datasette.database import QueryInterrupted +from datasette.utils.sqlite import sqlite3 + +# The names as they appear on the wire, written out rather than read from the +# registry. If a change to the registry makes one of these fail, that change +# is renaming something a user's dashboards and saved queries depend on - +# which is a decision to take deliberately, here, not a line to re-derive. +EXPECTED_ATTRIBUTES = { + "db.query": { + "db.system", + "db.namespace", + "db.query.text", + "db.operation.name", + "db.collection.name", + "datasette.param_count", + "datasette.param_sets", + "datasette.time_limit_ms", + "datasette.rows_returned", + "datasette.truncated", + "datasette.interrupted", + "datasette.sql_error_suppressed", + "datasette.executescript", + "datasette.executemany", + }, + "db.query.execute": set(), + "db.write.queue_wait": set(), + "db.write.execute": { + "datasette.isolated_connection", + "datasette.transaction", + }, + "datasette.startup": set(), +} +EXPECTED_SPANS = set(EXPECTED_ATTRIBUTES) + +# Named in-memory databases are shared-cache, so two Datasette instances using +# the same name share one SQLite database - and the second `create table` +# fails. Every workload below therefore gets its own name. +_names = itertools.count() + + +def _unique(prefix): + return f"{prefix}{next(_names)}" + + +async def exercise(): + """ + Drive enough of Datasette to emit every span and attribute the registry + claims exists. + + Each call is here because it is the only thing that produces some span or + attribute - see the comments. If you add instrumentation on a path this + does not reach, add the path rather than loosening the assertions. + + Returns the instance so the caller can close it; startup happens inside + so that the `datasette.startup` span lands in the collected set. + """ + name = _unique("registry") + ds = Datasette(memory=True) + ds.add_memory_database(name) + # datasette.startup - and the internal catalog work nested under it + await ds.invoke_startup() + db = ds.get_database(name) + + # Writes: db.write.queue_wait, db.write.execute, db.query + await db.execute_write("create table t (id integer primary key, v text)") + # datasette.executemany, datasette.param_sets + await db.execute_write_many( + "insert into t (id, v) values (?, ?)", [[i, f"v{i}"] for i in range(30)] + ) + # datasette.executescript + await db.execute_write_script("create table t2 (id integer); drop table t2;") + # datasette.transaction=False - VACUUM cannot run inside a transaction + await db.execute_write("vacuum", transaction=False) + # datasette.isolated_connection=True + await db.execute_isolated_fn(lambda conn: conn.execute("select 1").fetchone()) + + # Reads: db.query.execute, datasette.rows_returned, datasette.truncated, + # datasette.param_count, datasette.time_limit_ms + await db.execute("select * from t where id > :n", {"n": 5}) + await db.execute("select * from t", truncate=True) + + # datasette.sql_error_suppressed - the caller is probing and treats + # failure as an expected answer + with pytest.raises(sqlite3.OperationalError): + await db.execute("select nope from t", log_sql_errors=False) + + # datasette.interrupted - only ever set when a query exceeds its time + # limit, so the workload has to force one rather than exempt it. An + # unbounded recursive CTE cannot finish, so 1ms is always exceeded. + with pytest.raises(QueryInterrupted): + await db.execute( + "with recursive c(x) as (select 0 union all select x+1 from c) " + "select * from c", + custom_time_limit=1, + ) + + # db.collection.name - set only by views that already know their table + assert (await ds.client.get(f"/{name}/t?_facet=v")).status_code == 200 + assert (await ds.client.get(f"/{name}/t/1.json")).status_code == 200 + return ds + + +@pytest_asyncio.fixture +async def emitted(otel_spans): + "Every span name and (span name, attribute key) pair a broad workload emits." + # otel_spans has already cleared the exporter, and nothing is cleared + # after this point: the workload's own startup emits datasette.startup. + ds = await exercise() + spans = otel_spans.get_finished_spans() + assert spans, "no spans captured - the fixture is not exercising anything" + names = set() + pairs = set() + for span in spans: + # str() because span.name is the registry's SpanName instance, and a + # set of those would compare equal to literals but read confusingly + # in a failure message. + names.add(str(span.name)) + for key in span.attributes or {}: + pairs.add((str(span.name), str(key))) + ds.close() + return {"names": names, "pairs": pairs} + + +def _keys_by_span(pairs): + by_span = {} + for span_name, key in pairs: + by_span.setdefault(span_name, set()).add(key) + return by_span + + +@pytest.mark.asyncio +async def test_workload_emits_exactly_the_expected_names(emitted): + """ + The wire format, pinned to literals. + + Not derived from the registry, so this is what catches a rename that the + registry and the call sites make together. + """ + assert emitted["names"] == EXPECTED_SPANS + by_span = _keys_by_span(emitted["pairs"]) + assert {name: by_span.get(name, set()) for name in emitted["names"]} == ( + EXPECTED_ATTRIBUTES + ) + + +def test_registry_matches_the_expected_names(): + "The other half of the rename check: the registry against the same literals." + assert {str(span) for span in reg.SPANS} == EXPECTED_SPANS + for span in reg.SPANS: + assert {str(attribute) for attribute in span.attributes} == EXPECTED_ATTRIBUTES[ + str(span) + ], f"{span} attributes have drifted" + + +@pytest.mark.asyncio +async def test_every_emitted_span_is_registered(emitted): + "A span added without a registry entry would be missing from the docs." + unregistered = sorted( + name for name in emitted["names"] if reg.span_for(name) is None + ) + assert ( + not unregistered + ), f"these spans are emitted but not in telemetry_registry.SPANS: {unregistered}" + + +@pytest.mark.asyncio +async def test_every_emitted_attribute_is_registered(emitted): + "An attribute added without a registry entry would be missing from the docs." + unregistered = sorted( + f"{span_name} -> {key}" + for span_name, key in emitted["pairs"] + if not reg.attribute_allowed(reg.span_for(span_name), key) + ) + assert ( + not unregistered + ), "these span attributes are emitted but not registered: " + ", ".join( + unregistered + ) + + +@pytest.mark.asyncio +async def test_every_registered_span_is_emitted(emitted): + """ + The direction nothing else catches: the docs must not describe a span that + no longer exists. + """ + missing = sorted( + str(span) + for span in reg.SPANS + if not any(reg.span_for(name) is span for name in emitted["names"]) + ) + assert not missing, ( + f"these spans are documented but never emitted by the workload: {missing}. " + "Either the instrumentation was removed, or exercise() no longer reaches it." + ) + + +@pytest.mark.asyncio +async def test_every_registered_attribute_is_emitted(emitted): + """ + Every registered attribute, optional or not, must actually be set at least + once by the workload. + + `optional` describes whether a reader should expect it on every span, not + whether the code still sets it - so an attribute deleted from the code but + left in the docs has to fail here even when it is marked optional. If a + new attribute only appears in some rare case, extend exercise() to reach + that case. + """ + by_span = _keys_by_span(emitted["pairs"]) + missing = [] + for span in reg.SPANS: + emitted_keys = by_span.get(str(span), set()) + for attribute in span.attributes: + if attribute not in emitted_keys: + missing.append(f"{span} -> {attribute}") + assert not missing, ( + "these attributes are documented but never emitted by the workload: " + + ", ".join(sorted(missing)) + ) + + +def test_registry_has_no_duplicate_names(): + assert len(set(reg.SPANS)) == len(reg.SPANS) + for span in reg.SPANS: + assert len(set(span.attributes)) == len( + span.attributes + ), f"{span} lists an attribute twice" + + +def test_registry_entries_are_documented(): + "Every entry carries a description - the docs are generated from these." + for span in reg.SPANS: + assert span.description.strip(), f"{span} has no description" + for attribute in span.attributes: + assert attribute.description.strip(), f"{span} -> {attribute} has none" + + +def test_registry_entries_are_usable_as_plain_strings(): + "The str subclassing is the whole reason call sites need no wrapper API." + assert isinstance(reg.DB_QUERY, str) + assert isinstance(reg.DB_NAMESPACE, str) + assert reg.DB_QUERY == "db.query" + assert reg.DB_NAMESPACE == "db.namespace" + assert f"{reg.DB_QUERY}.execute" == "db.query.execute" + + +def test_span_and_attribute_lookup(): + assert reg.span_for("db.query") is reg.DB_QUERY + assert reg.span_for("datasette.startup") is reg.STARTUP + assert reg.span_for("not.a.datasette.span") is None + assert reg.attribute_allowed(reg.DB_QUERY, "db.namespace") + assert not reg.attribute_allowed(reg.DB_QUERY, "db.namespace.extra") + assert not reg.attribute_allowed(reg.DB_QUERY, "datasette.isolated_connection") + assert not reg.attribute_allowed(None, "db.namespace") + + +def test_prefix_span_lookup(): + """ + `prefix=True` matching, exercised directly. + + Phase 1 registers no prefix spans, so without this the branch in + `span_for()` would be untested code that the conformance tests silently + never reach. + """ + hook = reg.SpanName("datasette.hook.", "A hypothetical span family", prefix=True) + original = reg.SPANS + reg.SPANS = original + (hook,) + try: + assert reg.span_for("datasette.hook.render_cell") is hook + assert reg.span_for("datasette.hook.anything") is hook + assert reg.span_for("datasette.hookish") is None + assert reg.span_for("db.query") is reg.DB_QUERY + finally: + reg.SPANS = original