adding sample for assigning severity category for your application error

Author: deepika-awasthi

benign_application_error/README.md

@@ -0,0 +1,52 @@
+# Benign Application Error
+This sample shows how to use ApplicationError(category=BENIGN) in the Python SDK.
+It demonstrates how the BENIGN error category affects logging severity and metrics emission for activity failures.
+
+BENIGN ApplicationError
+Activity failure is logged only at DEBUG level, otherwise no logging at the logger streaming (uncomment setLevel at line 15 in worker.py to check the logs)
+No activity failure metrics are emitted.
+
+Non-BENIGN ApplicationError
+Activity failure is logged at WARN/ERROR.
+Activity failure metrics are emitted.
+
+This makes BENIGN useful for "expected" failure paths where noisy WARN logs and metrics are not desired.
+
+Dependencies
+For this sample, the optional python=json-logger dependency group must be included. To include, run:
+    `uv sync`
+    
+Running the Sample
+
+Start the worker in one terminal:
+`    uv run benign_application_error/worker.py
+`    
+
+This will start a worker that registers the workflow and activity.
+In another terminal, run the starter to execute the workflows:
+
+`    uv run benign_application_error/starter.py
+`
+Expected Behavior
+
+The first workflow runs with BENIGN=True and will not do any logging.
+No failure metrics are emitted.
+
+The second workflow runs with BENIGN=False. The activity fails, and the worker logs a WARN entry.
+Failure metrics are emitted.
+
+`running worker....
+{"message": "Completing activity as failed ({'activity_id': '1', 'activity_type': 'greeting_activities', 'attempt': 1, 'namespace': 'default', 'task_queue': 'benign_application_error_task_queue', 'workflow_id': 'benign_application_error-wf-2', 'workflow_run_id': '0199828f-af08-7a19-ac0f-eed01a7f1974', 'workflow_type': 'BenignApplicationErrorWorkflow'})", "exc_info": "Traceback (most recent call last):\n  File \"/Users/deepikaawasthi/temporal/my-local-python-samples/samples-python/.venv/lib/python3.13/site-packages/temporalio/worker/_activity.py\", line 297, in _handle_start_activity_task\n    result = await self._execute_activity(start, running_activity, task_token)\n             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/Users/deepikaawasthi/temporal/my-local-python-samples/samples-python/.venv/lib/python3.13/site-packages/temporalio/worker/_activity.py\", line 610, in _execute_activity\n    return await impl.execute_activity(input)\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/Users/deepikaawasthi/temporal/my-local-python-samples/samples-python/.venv/lib/python3.13/site-packages/temporalio/worker/_activity.py\", line 805, in execute_activity\n    return await input.fn(*input.args)\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/Users/deepikaawasthi/temporal/my-local-python-samples/samples-python/benign_application_error/activities.py\", line 15, in greeting_activities\n    raise ApplicationError(\"Without benign flag : Greeting not sent\")\ntemporalio.exceptions.ApplicationError: Without benign flag : Greeting not sent", "temporal_activity": {"activity_id": "1", "activity_type": "greeting_activities", "attempt": 1, "namespace": "default", "task_queue": "benign_application_error_task_queue", "workflow_id": "benign_application_error-wf-2", "workflow_run_id": "0199828f-af08-7a19-ac0f-eed01a7f1974", "workflow_type": "BenignApplicationErrorWorkflow"}}
+`
+
+Both workflows will still raise exceptions back to the starter, which you can see printed in the console.
+
+Inspecting Workflows
+
+Use the Temporal CLI to view workflow results:
+
+`temporal workflow show --workflow-id benign_application_error-wf-1
+temporal workflow show --workflow-id benign_application_error-wf-2`
+
+
+Both workflows will show failure status, but only the Non-BENIGN run produces WARN logs and metrics.

benign_application_error/activities.py

@@ -0,0 +1,15 @@
+import asyncio
+from temporalio import activity
+from temporalio.exceptions import ApplicationError, ApplicationErrorCategory
+
+@activity.defn
+async def greeting_activities(use_benign: bool) -> None:
+
+    #BENIGN category errors emit DEBUG level logs and do not record metrics
+    if use_benign:
+        raise ApplicationError(
+            message="With benign flag : Greeting not sent",
+            category=ApplicationErrorCategory.BENIGN,
+        )
+    else:
+        raise ApplicationError("Without benign flag : Greeting not sent")

benign_application_error/starter.py

@@ -0,0 +1,42 @@
+import asyncio
+import logging
+from pythonjsonlogger import json
+from temporalio.client import Client
+from benign_application_error.worker import set_init_runtime
+from benign_application_error.workflow import BenignApplicationErrorWorkflow
+
+
+async def main():
+    runtime = set_init_runtime()
+
+    client = await Client.connect(
+        "localhost:7233",
+        runtime=runtime,
+    )
+
+    # BENIGN=True
+    try:
+        await client.execute_workflow(
+            BenignApplicationErrorWorkflow.run,
+            True,
+            id="benign_application_error-wf-1",
+            task_queue="benign_application_error_task_queue",
+        )
+    except Exception as e:
+        logging.debug(f"BENIGN=True run finished with exception: {e}")
+
+    # BENIGN=False
+    try:
+        await client.execute_workflow(
+            BenignApplicationErrorWorkflow.run,
+            False,
+            id="benign_application_error-wf-2",
+            task_queue="benign_application_error_task_queue",
+        )
+    except Exception as e:
+        logging.debug(f"BENIGN=False run finished with exception: {e}")
+
+
+
+if __name__ == "__main__":
+    asyncio.run(main())

benign_application_error/worker.py

@@ -0,0 +1,55 @@
+import asyncio
+import logging
+
+from pythonjsonlogger import json
+from temporalio.runtime import Runtime, TelemetryConfig, LogForwardingConfig, LoggingConfig
+from temporalio.worker import Worker
+from temporalio.client import Client
+
+from benign_application_error.workflow import BenignApplicationErrorWorkflow
+from benign_application_error.activities import greeting_activities
+
+
+def configure_json_logger() -> logging.Logger:
+    logger = logging.getLogger()
+#     logger.setLevel(logging.DEBUG) # set level to DEBUG and observe the difference
+    handler = logging.StreamHandler()
+    handler.setFormatter(json.JsonFormatter())
+    logger.handlers.clear()
+    logger.addHandler(handler)
+    return logger
+
+def set_init_runtime() -> Runtime:
+    app_err_logger = configure_json_logger()
+
+    return  Runtime(
+                    telemetry=TelemetryConfig(
+                               logging=LoggingConfig(
+                                    LoggingConfig.default.filter,
+                                    forwarding=LogForwardingConfig(logger = app_err_logger),
+                               )
+                          )
+                    )
+
+
+async def main():
+    # Configuring logger
+    runtime = set_init_runtime()
+
+    client = await Client.connect(
+            "localhost:7233",
+            runtime=runtime,
+    )
+
+    worker = Worker(
+        client=client,
+        task_queue="benign_application_error_task_queue",
+        workflows=[BenignApplicationErrorWorkflow],
+        activities=[greeting_activities],
+    )
+    print("running worker....")
+
+    await worker.run()
+
+if __name__ == "__main__":
+    asyncio.run(main())

benign_application_error/workflow.py

@@ -0,0 +1,16 @@
+from datetime import timedelta
+from temporalio import workflow
+from temporalio.common import RetryPolicy
+from benign_application_error.activities import greeting_activities
+
+@workflow.defn
+class BenignApplicationErrorWorkflow:
+    @workflow.run
+    async def run(self, use_benign: bool) -> None:
+        await workflow.execute_activity(
+            greeting_activities,
+            use_benign,
+            start_to_close_timeout=timedelta(seconds=5),
+            schedule_to_close_timeout=timedelta(seconds=5),
+            retry_policy=RetryPolicy(maximum_attempts=1),
+        )

pyproject.toml

@@ -26,6 +26,8 @@ dev = [
     "types-pyyaml>=6.0.12.20241230,<7",
     "pytest-pretty>=1.3.0",
     "poethepoet>=0.36.0",
+    "python-json-logger>=2.0.7",
+
 ]
 bedrock = ["boto3>=1.34.92,<2"]
 dsl = [