From a314b761866d250c16f1ff6dd682010cf4181eb4 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Wed, 2 Oct 2019 08:32:47 -0700
Subject: [PATCH] Added /-/threads debugging page

---
 datasette/app.py       | 13 +++++++++++++
 docs/introspection.rst | 25 +++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/datasette/app.py b/datasette/app.py
index 501d1467..41a4eb37 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -457,6 +457,15 @@ class Datasette:
             for p in ps
         ]
 
+    def threads(self):
+        threads = list(threading.enumerate())
+        return {
+            "num_threads": len(threads),
+            "threads": [
+                {"name": t.name, "ident": t.ident, "daemon": t.daemon} for t in threads
+            ],
+        }
+
     def table_metadata(self, database, table):
         "Fetch table-specific metadata."
         return (
@@ -621,6 +630,10 @@ class Datasette:
             JsonDataView.as_asgi(self, "config.json", lambda: self._config),
             r"/-/config(?P<as_format>(\.json)?)$",
         )
+        add_route(
+            JsonDataView.as_asgi(self, "threads.json", self.threads),
+            r"/-/threads(?P<as_format>(\.json)?)$",
+        )
         add_route(
             JsonDataView.as_asgi(self, "databases.json", self.connected_databases),
             r"/-/databases(?P<as_format>(\.json)?)$",
diff --git a/docs/introspection.rst b/docs/introspection.rst
index e514ddf5..02552bab 100644
--- a/docs/introspection.rst
+++ b/docs/introspection.rst
@@ -90,6 +90,8 @@ Shows the :ref:`config` options for this instance of Datasette. `Config example
         "sql_time_limit_ms": 1000
     }
 
+.. _JsonDataView_databases:
+
 /-/databases
 ------------
 
@@ -105,3 +107,26 @@ Shows currently attached databases. `Databases example <https://latest.datasette
             "size": 225280
         }
     ]
+
+.. _JsonDataView_threads:
+
+/-/threads
+----------
+
+Shows details of threads. `Threads example <https://latest.datasette.io/-/threads>`_::
+
+    {
+        "num_threads": 2,
+        "threads": [
+            {
+                "daemon": false,
+                "ident": 4759197120,
+                "name": "MainThread"
+            },
+            {
+                "daemon": true,
+                "ident": 123145319682048,
+                "name": "Thread-1"
+            },
+        ]
+    }