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46961efee2
Datasette core is gaining OpenTelemetry spans alongside the existing hand-rolled tracer. This commit only lays the groundwork - no span is emitted yet. Core takes a runtime dependency on opentelemetry-api and nothing more. It deliberately never creates a TracerProvider, configures an exporter, or touches sampling: that belongs to whoever runs Datasette, normally via an opentelemetry-instrument agent. Owning a provider in core was tried in an earlier design and produced a cross-request span leak, a process-global provider that tests could not tear down, and a sampling env var that silently blanked output. With no provider installed every span is a NonRecordingSpan and costs approximately nothing. datasette/telemetry.py exposes the module-level tracer plus sql_attribute(), which truncates SQL to 2048 characters. On a public instance the SQL is attacker-controlled and unbounded - someone can paste a 10MB query into ?sql= - so it must never reach a telemetry pipeline verbatim. opentelemetry-sdk goes in the dev dependency group only, because the test suite needs it to assert on spans while the package itself must not import it. tests/test_telemetry.py enforces that by importing datasette in a fresh interpreter and inspecting sys.modules, which catches a lazy import inside a function body that a grep would miss. conftest.py gains a session-scoped autouse fixture installing an SDK provider with an InMemorySpanExporter. It has to be session-scoped because set_tracer_provider() is effectively once-per-process - a second call logs a warning and is ignored. SimpleSpanProcessor rather than BatchSpanProcessor, so assertions made right after a request never race a background export thread. The otel_spans fixture that later tickets assert against is added here too. test_datasette_package_never_imports_the_sdk is moved to the front of the run. Late in a serial run the pytest process holds enough threads that the fork half of subprocess' fork+exec segfaults the interpreter on macOS/CPython 3.13. That reproduces with any subprocess call in that position on an unmodified tree, so it is a pre-existing hazard rather than something this commit introduces; the repo already moves its other subprocess-spawning tests to the front for related reasons. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
25 lines
931 B
Python
25 lines
931 B
Python
import subprocess
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import sys
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def test_datasette_package_never_imports_the_sdk():
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"""
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Core depends on opentelemetry-api only. The SDK is a test dependency.
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Checked by importing datasette in a fresh process and inspecting
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sys.modules, rather than by grepping, so a lazy `import
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opentelemetry.sdk` inside a function body cannot slip past.
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conftest.py's pytest_collection_modifyitems() moves this test to the
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front of the run by name - if you rename it, rename it there too.
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"""
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code = (
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"import datasette.app, datasette.database, datasette.telemetry, sys; "
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"print([m for m in sys.modules if m.startswith('opentelemetry.sdk')])"
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)
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result = subprocess.run(
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[sys.executable, "-c", code], capture_output=True, text=True, check=True
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)
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assert (
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result.stdout.strip() == "[]"
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), f"datasette imported the OpenTelemetry SDK: {result.stdout.strip()}"
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