Merge pull request #2444 from PrefectHQ/log-json

Pop args out of log messages to prevent shipping non-JSON objects

CHANGELOG.md

@@ -19,6 +19,7 @@ These changes are available in the [master branch](https://github.com/PrefectHQ/
 ### Fixes
 
 - Fix `server start` CLI command not respecting `version` kwarg on tagged releases - [#2435](https://github.com/PrefectHQ/prefect/pull/2435)
+- Fix issue with non-JSON serializable args being used to format log messages preventing them from shipping to Cloud - [#2407](https://github.com/PrefectHQ/prefect/issues/2407)
 
 ### Deprecations
 

src/prefect/utilities/logging.py

@@ -130,6 +130,9 @@ def emit(self, record) -> None:  # type: ignore
             assert isinstance(self.client, Client)  # mypy assert
 
             record_dict = record.__dict__.copy()
+            ## remove potentially non-json serializable formatting args
+            record_dict.pop("args", None)
+
             log = dict()
             log["flow_run_id"] = prefect.context.get("flow_run_id", None)
             log["task_run_id"] = prefect.context.get("task_run_id", None)

tests/utilities/test_logging.py

@@ -135,6 +135,32 @@ def test_remote_handler_captures_tracebacks(caplog, monkeypatch):
         logger.handlers = []
 
 
+def test_cloud_handler_formats_messages_and_removes_args(caplog, monkeypatch):
+    monkeypatch.setattr("prefect.client.Client", MagicMock)
+    client = MagicMock()
+    try:
+        with utilities.configuration.set_temporary_config(
+            {"logging.log_to_cloud": True}
+        ):
+            logger = utilities.logging.configure_logging(testing=True)
+            assert hasattr(logger.handlers[-1], "client")
+            logger.handlers[-1].client = client
+
+            child_logger = logger.getChild("sub-test")
+            child_logger.info("Here's a number: %d", 42)
+
+            time.sleep(0.75)
+
+            cloud_logs = client.write_run_logs.call_args[0][0]
+            assert len(cloud_logs) == 1
+            assert cloud_logs[0]["message"] == "Here's a number: 42"
+            assert "args" not in cloud_logs[0]["info"]
+    finally:
+        # reset root_logger
+        logger = utilities.logging.configure_logging(testing=True)
+        logger.handlers = []
+
+
 def test_remote_handler_ships_json_payloads(caplog, monkeypatch):
     monkeypatch.setattr("prefect.client.Client", MagicMock)
     client = MagicMock()