Add log streaming to papermill plugin

plugins/flytekit-papermill/flytekitplugins/papermill/task.py

@@ -1,5 +1,7 @@
 import json
+import logging
 import os
+import sys
 import typing
 from typing import Any
 
@@ -84,6 +86,13 @@ class NotebookTask(PythonInstanceTask[T]):
 
         Users can access these notebooks after execution of the task locally or from remote servers.
 
+    .. note:
+
+        By default, print statements in your notebook won't be transmitted to the pod logs/stdout. If you would
+        like to have logs forwarded as the notebook executes, pass the stream_logs argument. Note that notebook
+        logs can be quite verbose, so ensure you are prepared for any downstream log ingestion costs
+        (e.g., cloudwatch)
+
     .. todo:
 
         Implicit extraction of SparkConfiguration from the notebook is not supported.
@@ -112,6 +121,7 @@ def __init__(
         name: str,
         notebook_path: str,
         render_deck: bool = False,
+        stream_logs: bool = False,
         task_config: T = None,
         inputs: typing.Optional[typing.Dict[str, typing.Type]] = None,
         outputs: typing.Optional[typing.Dict[str, typing.Type]] = None,
@@ -132,6 +142,16 @@ def __init__(
         self._notebook_path = os.path.abspath(notebook_path)
 
         self._render_deck = render_deck
+        self._stream_logs = stream_logs
+
+        # Send the papermill logger to stdout so that it appears in pod logs. Note that papermill doesn't allow
+        # injecting a logger, so we cannot redirect logs to the flyte child loggers (e.g., the userspace logger)
+        # and inherit their settings, but we instead must send logs to stdout directly
+        if self._stream_logs:
+            papermill_logger = logging.getLogger("papermill")
+            papermill_logger.addHandler(logging.StreamHandler(sys.stdout))
+            # Papermill leaves the default level of DEBUG. We increase it here.
+            papermill_logger.setLevel(logging.INFO)
 
         if not os.path.exists(self._notebook_path):
             raise ValueError(f"Illegal notebook path passed in {self._notebook_path}")
@@ -207,7 +227,7 @@ def execute(self, **kwargs) -> Any:
         """
         logger.info(f"Hijacking the call for task-type {self.task_type}, to call notebook.")
         # Execute Notebook via Papermill.
-        pm.execute_notebook(self._notebook_path, self.output_notebook_path, parameters=kwargs)  # type: ignore
+        pm.execute_notebook(self._notebook_path, self.output_notebook_path, parameters=kwargs, log_output=self._stream_logs)  # type: ignore
 
         outputs = self.extract_outputs(self.output_notebook_path)
         self.render_nb_html(self.output_notebook_path, self.rendered_output_path)