feat: support for event loop debugging and slow tasks detection

azure_functions_worker/constants.py

@@ -93,3 +93,8 @@
 
 # Appsetting to specify AppInsights connection string
 APPLICATIONINSIGHTS_CONNECTION_STRING = "APPLICATIONINSIGHTS_CONNECTION_STRING"
+
+# New constant for event loop profiling
+PYTHON_ENABLE_EVENT_LOOP_DEBUGGING = 'PYTHON_ENABLE_EVENT_LOOP_DEBUGGING'
+PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD = 'PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBAK_THRESHOLD'
+PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD_DEFAULT = 600 # 10 minutes

azure_functions_worker/dispatcher.py

@@ -28,7 +28,10 @@
     METADATA_PROPERTIES_WORKER_INDEXED,
     PYTHON_AZURE_MONITOR_LOGGER_NAME,
     PYTHON_AZURE_MONITOR_LOGGER_NAME_DEFAULT,
+    PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD,
+    PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD_DEFAULT,
     PYTHON_ENABLE_DEBUG_LOGGING,
+    PYTHON_ENABLE_EVENT_LOOP_DEBUGGING,
     PYTHON_ENABLE_INIT_INDEXING,
     PYTHON_ENABLE_OPENTELEMETRY,
     PYTHON_ENABLE_OPENTELEMETRY_DEFAULT,
@@ -353,6 +356,15 @@ def update_opentelemetry_status(self):
                 "Cannot import OpenTelemetry libraries."
             )
 
+
+    def _setup_event_loop_profiling(self):
+        if is_envvar_true(PYTHON_ENABLE_EVENT_LOOP_DEBUGGING):
+            self._loop.set_debug(True)
+            self._loop.slow_callback_duration = get_app_setting(PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD, 
+                                                                PYTHON_DEBUGGING_EVENT_LOOP_SLOW_CALLBACK_THRESHOLD_DEFAULT)  # 10 minutes in seconds
+            logger.info("Event loop debug mode enabled with 10-minute slow callback detection")
+
+
     async def _handle__worker_init_request(self, request):
         logger.info('Received WorkerInitRequest, '
                     'python version %s, '
@@ -381,6 +393,10 @@ async def _handle__worker_init_request(self, request):
             constants.RPC_HTTP_TRIGGER_METADATA_REMOVED: _TRUE,
             constants.SHARED_MEMORY_DATA_TRANSFER: _TRUE,
         }
+
+        # Set up event loop profiling
+        self._setup_event_loop_profiling()
+
         if get_app_setting(setting=PYTHON_ENABLE_OPENTELEMETRY,
                            default_value=PYTHON_ENABLE_OPENTELEMETRY_DEFAULT):
             self.initialize_azure_monitor()
@@ -760,7 +776,9 @@ async def _handle__function_environment_reload_request(self, request):
             env_vars = func_env_reload_request.environment_variables
             for var in env_vars:
                 os.environ[var] = env_vars[var]
-
+            # Enable event loop debug mode
+            self._setup_event_loop_profiling()
+
             # Apply PYTHON_THREADPOOL_THREAD_COUNT
             self._stop_sync_call_tp()
             self._sync_call_tp = (