Add back Kaggle notebook integration (https://github.com/tensorflow/cloud/pull/224). The change got reverted because of some copybara issue in (https://github.com/tensorflow/cloud/commit/e9c5e8759bebf7be0883154a13da07471446435a#diff-b5e4b83c53a04cd75cd395f4b75352333339f0f0c58fdb720a37910d189ae0f9)

src/python/tensorflow_cloud/core/preprocess.py

@@ -17,12 +17,17 @@
 from __future__ import division
 from __future__ import print_function
 
+import io
+import logging
 import os
 import sys
 import tempfile
 
 from . import machine_config
 
+logger = logging.getLogger(__name__)
+logging.basicConfig(level=logging.INFO)
+
 try:
     from nbconvert import PythonExporter  # pylint: disable=g-import-not-at-top
 except ImportError:
@@ -164,7 +169,13 @@ def get_preprocessed_entry_point(
             'exec(open("{}").read())\n'.format(entry_point_file_name))
     else:
         if called_from_notebook:
-            py_content = _get_colab_notebook_content()
+            # Kaggle integration
+            if os.getenv("KAGGLE_CONTAINER_NAME"):
+                logger.info("Preprocessing Kaggle notebook...")
+                py_content = _get_kaggle_notebook_content()
+            else:
+                # Colab integration
+                py_content = _get_colab_notebook_content()
         else:
             if PythonExporter is None:
                 raise RuntimeError(
@@ -212,6 +223,25 @@ def _get_colab_notebook_content():
     return py_content
 
 
+def _get_kaggle_notebook_content():
+    """Returns the kaggle notebook python code contents."""
+    if PythonExporter is None:
+        raise RuntimeError(
+            # This should never occur.
+            # `nbconvert` is always installed on Kaggle.
+            "Please make sure you have installed `nbconvert` package."
+        )
+    from kaggle_session import UserSessionClient  # pylint: disable=g-import-not-at-top  # pytype: disable=import-error
+    kaggle_session_client = UserSessionClient()
+    try:
+        response = kaggle_session_client.get_exportable_ipynb()
+        ipynb_stream = io.StringIO(response["source"])
+        py_content, _ = PythonExporter().from_file(ipynb_stream)
+        return py_content.splitlines(keepends=True)
+    except:
+        raise RuntimeError("Unable to get the notebook contents.")
+
+
 def get_tpu_cluster_resolver_fn():
     """Returns the fn required for runnning custom container on cloud TPUs.