Added exception handling to bot_session.

Will also return the stderr and stdout to user.

buildgrid/bot/bot_session.py

@@ -12,6 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Disable broad exception catch
+# pylint: disable=broad-except
+
 
 """
 Bot Session
@@ -23,10 +26,14 @@ import asyncio
 import logging
 import platform
 import uuid
-
 from enum import Enum
 
+import grpc
+from google.protobuf import any_pb2
+
 from buildgrid._protos.google.devtools.remoteworkers.v1test2 import bots_pb2, worker_pb2
+from buildgrid._protos.build.bazel.remote.execution.v2 import remote_execution_pb2
+from buildgrid._exceptions import BotError
 
 
 class BotStatus(Enum):
@@ -142,13 +149,37 @@ class BotSession:
 
     async def create_work(self, lease):
         self.logger.debug("Work created: [{}]".format(lease.id))
-
+        input_lease = lease
         loop = asyncio.get_event_loop()
-        lease = await loop.run_in_executor(None, self._work, self._context, lease)
+
+        try:
+            lease = await loop.run_in_executor(None, self._work, self._context, lease)
+
+        except BotError as e:
+            self.logger.error("Bot error thrown: [{}]".format(e))
+            lease = self._lease_error(input_lease, e)
+
+        except grpc.RpcError as e:
+            self.logger.error("Connection error thrown: [{}]".format(e))
+            lease = self._lease_error(input_lease, e)
+
+        except Exception as e:
+            self.logger.error("Connection error thrown: [{}]".format(e))
+            lease = self._lease_error(input_lease, e)
 
         self.logger.debug("Work complete: [{}]".format(lease.id))
         self.lease_completed(lease)
 
+    def _lease_error(self, lease, error):
+        action_result = remote_execution_pb2.ActionResult()
+        action_result.stderr_raw = str(error)
+        action_result.exit_code = -1
+
+        action_result_any = any_pb2.Any()
+        action_result_any.Pack(action_result)
+        lease.result.CopyFrom(action_result_any)
+        return lease
+
 
 class Worker:
     def __init__(self, properties=None, configs=None):