[Findit] Implementing swarming task error detection

appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import copy
 import logging
 import time
 
 from common.http_client_appengine import HttpClientAppengine as HttpClient
 from common.pipeline_wrapper import BasePipeline
@@ skipping 150 matching lines @@
         ref_task_id, http_client)
 
     # 2. Update/Overwrite parameters for the re-run.
     iterations_to_rerun = self._GetIterationsToRerun()
 
     new_request = self._CreateNewSwarmingTaskRequest(
         ref_task_id, ref_request, master_name, builder_name, build_number,
         step_name, tests, iterations_to_rerun)
 
     # 3. Trigger a new Swarming task to re-run the failed tests.
-    task_id = swarming_util.TriggerSwarmingTask(new_request, http_client)
+    task_id, error = swarming_util.TriggerSwarmingTask(new_request, http_client)
 
     # Save the task id.
     swarming_task = self._GetSwarmingTask(*call_args)
     swarming_task.task_id = task_id

[chanli, 2016/11/11 00:05:13]

If the swarming_task is not even triggered, should we save the None task_id and
parameters of the request?

[lijeffrey, 2016/11/11 20:55:41]

I think we can still save the parameters, but they wouldn't get used. This can
be a design choice, I can't think of a clear reason why or why not to go either
way. Maybe in case we want to implement retry with the same parameters as before
that failed, but I don't feel strongly about going either way

+    if error:
+      swarming_task.error = error
     swarming_task.parameters['tests'] = tests
     swarming_task.parameters['iterations_to_rerun'] = iterations_to_rerun
     swarming_task.parameters['ref_name'] = swarming_util.GetTagValue(
         new_request.tags, 'ref_name')
     swarming_task.put()
 
     logging.info('A Swarming task was triggered:%s', task_id)

[chanli, 2016/11/11 00:05:13]

If error, we shouldn't have this log.

[lijeffrey, 2016/11/11 20:55:41]

Done.

     return task_id