feat: Support OpenTelemetry Azure monitor distro

azure_functions_worker/constants.py

@@ -81,5 +81,15 @@
 # Base extension supported Python minor version
 BASE_EXT_SUPPORTED_PY_MINOR_VERSION = 8
 
+# Appsetting to turn on OpenTelemetry support/features
+# Includes turning on Azure monitor distro to send telemetry to AppInsights
 PYTHON_ENABLE_OPENTELEMETRY = "PYTHON_ENABLE_OPENTELEMETRY"
-PYTHON_ENABLE_OPENTELEMETRY_DEFAULT = True
+PYTHON_ENABLE_OPENTELEMETRY_DEFAULT = False
+
+# Appsetting to specify root logger name of logger to collect telemetry for
+# Used by Azure monitor distro
+PYTHON_AZURE_MONITOR_LOGGER_NAME = "PYTHON_AZURE_MONITOR_LOGGER_NAME"
+PYTHON_AZURE_MONITOR_LOGGER_NAME_DEFAULT = ""
+
+# Appsetting to specify AppInsights connection string
+APPLICATIONINSIGHTS_CONNECTION_STRING = "APPLICATIONINSIGHTS_CONNECTION_STRING"

azure_functions_worker/dispatcher.py

@@ -288,6 +288,46 @@ async def _dispatch_grpc_request(self, request):
         resp = await request_handler(request)
         self._grpc_resp_queue.put_nowait(resp)
 
+    def initialize_opentelemetry(self):
+        """Initializes OpenTelemetry and Azure monitor distro
+        """
+        self.update_opentelemetry_status()
+        try:
+            from azure.monitor.opentelemetry import configure_azure_monitor
+
+            # Set functions resource detector manually until officially
+            # include in Azure monitor distro
+            os.environ.setdefault(
+                "OTEL_EXPERIMENTAL_RESOURCE_DETECTORS",
+                "azure_functions",
+            )
+
+            configure_azure_monitor(
+                # Connection string can be explicitly specified in Appsetting
+                # If not set, defaults to env var
+                # APPLICATIONINSIGHTS_CONNECTION_STRING
+                connection_string=get_app_setting(
+                    setting=APPLICATIONINSIGHTS_CONNECTION_STRING
+                ),
+                logger_name=get_app_setting(
+                    setting=PYTHON_AZURE_MONITOR_LOGGER_NAME,
+                    default_value=PYTHON_AZURE_MONITOR_LOGGER_NAME_DEFAULT
+                ),
+            )
+            self._otel_libs_available = True
+
+            logger.info("Successfully configured Azure monitor distro.")
+        except ImportError:
+            logger.exception(
+                "Cannot import Azure Monitor distro."
+            )
+            self._otel_libs_available = False
+        except Exception:
+            logger.exception(
+                "Error initializing Azure monitor distro."
+            )
+            self._otel_libs_available = False
+
     def update_opentelemetry_status(self):
         """Check for OpenTelemetry library availability and
         update the status attribute."""
@@ -334,10 +374,9 @@ async def _handle__worker_init_request(self, request):
             constants.RPC_HTTP_TRIGGER_METADATA_REMOVED: _TRUE,
             constants.SHARED_MEMORY_DATA_TRANSFER: _TRUE,
         }
-
         if get_app_setting(setting=PYTHON_ENABLE_OPENTELEMETRY,
                            default_value=PYTHON_ENABLE_OPENTELEMETRY_DEFAULT):
-            self.update_opentelemetry_status()
+            self.initialize_opentelemetry()
 
             if self._otel_libs_available:
                 capabilities[constants.WORKER_OPEN_TELEMETRY_ENABLED] = _TRUE

tests/unittests/test_opentelemetry.py

@@ -33,9 +33,37 @@ def test_update_opentelemetry_status_success(
         self.assertTrue(self.dispatcher._otel_libs_available)
 
     @patch('builtins.__import__')
-    def test_init_request_otel_capability_enabled(
-            self, mock_imports):
+    @patch("azure_functions_worker.dispatcher.Dispatcher.update_opentelemetry_status")
+    def test_initialize_opentelemetry_success(
+        self,
+        mock_update_ot,
+        mock_imports,
+    ):
+        mock_imports.return_value = MagicMock()
+        self.dispatcher.initialize_opentelemetry()
+        mock_update_ot.assert_called_once()
+        self.assertTrue(self.dispatcher._otel_libs_available)
+
+    @patch("azure_functions_worker.dispatcher.Dispatcher.update_opentelemetry_status")
+    def test_initialize_opentelemetry_import_error(
+        self,
+        mock_update_ot,
+    ):
+        with patch('builtins.__import__', side_effect=ImportError):
+            self.dispatcher.initialize_opentelemetry()
+            mock_update_ot.assert_called_once()
+            # Verify that otel_libs_available is set to False due to ImportError
+            self.assertFalse(self.dispatcher._otel_libs_available)
+
+    @patch("azure_functions_worker.dispatcher.get_app_setting")
+    @patch('builtins.__import__')
+    def test_init_request_otel_capability_enabled_app_setting(
+            self,
+            mock_imports,
+            mock_app_setting,
+    ):
         mock_imports.return_value = MagicMock()
+        mock_app_setting.return_value = True
 
         init_request = protos.StreamingMessage(
             worker_init_request=protos.WorkerInitRequest(
@@ -55,7 +83,14 @@ def test_init_request_otel_capability_enabled(
         self.assertIn("WorkerOpenTelemetryEnabled", capabilities)
         self.assertEqual(capabilities["WorkerOpenTelemetryEnabled"], "true")
 
-    def test_init_request_otel_capability_disabled(self):
+    @patch("azure_functions_worker.dispatcher.Dispatcher.initialize_opentelemetry")
+    @patch("azure_functions_worker.dispatcher.get_app_setting")
+    def test_init_request_otel_capability_disabled_app_setting(
+        self,
+        mock_app_setting,
+        mock_initialize_ot,
+    ):
+        mock_app_setting.return_value = False
 
         init_request = protos.StreamingMessage(
             worker_init_request=protos.WorkerInitRequest(
@@ -70,5 +105,9 @@ def test_init_request_otel_capability_disabled(self):
         self.assertEqual(init_response.worker_init_response.result.status,
                          protos.StatusResult.Success)
 
+        # OpenTelemetry initialized not called
+        mock_initialize_ot.assert_not_called()
+
+        # Verify that WorkerOpenTelemetryEnabled capability is not set
         capabilities = init_response.worker_init_response.capabilities
         self.assertNotIn("WorkerOpenTelemetryEnabled", capabilities)