Waterfall components of regression range finder.

appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py

Index: appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py
diff --git a/appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py b/appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py
new file mode 100644
index 0000000000000000000000000000000000000000..ea43d38c8483ad88759edf9670a84f2f08b48373
--- /dev/null
+++ b/appengine/findit/waterfall/trigger_base_swarming_task_pipeline.py
@@ -0,0 +1,181 @@
+# 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
+from datetime import datetime
+import logging
+import time
+
+from google.appengine.ext import ndb
+
+from common.http_client_appengine import HttpClientAppengine as HttpClient
+from common.pipeline_wrapper import BasePipeline
+from model import analysis_status
+from waterfall import swarming_util
+from waterfall import waterfall_config
+
+
+class TriggerBaseSwarmingTaskPipeline(BasePipeline):
+  """A pipeline to trigger a Swarming task to re-run selected tests of a step.
+
+  This pipeline only supports test steps that run on Swarming and support the
+  gtest filter.
+  """
+
+  def _GetSwarmingTaskName(self, ref_task_id):  # pragma: no cover.
+    return 'findit/deflake/ref_task_id/%s/%s' % (
+        ref_task_id, datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S %f'))
+
+  def _CreateNewSwarmingTaskRequest(self, ref_task_id, ref_request, master_name,
+                                    builder_name, build_number,step_name,
+                                    tests, iterations):
+    """Returns a SwarmingTaskRequest instance to run the given tests only."""
+    # Make a copy of the referred request and drop or overwrite some fields.
+    new_request = copy.deepcopy(ref_request)
+    new_request.name = self._GetSwarmingTaskName(ref_task_id)
+    new_request.parent_task_id = ''
+    new_request.user = ''
+
+    # To force a fresh re-run and ignore cached result of any equivalent run.
+    new_request.idempotent = False
+
+    # Set the gtest_filter to run the given tests only.
+    new_request.extra_args.append('--gtest_repeat=%s' % iterations)
+    new_request.extra_args.append('--test-launcher-retry-limit=0')
+    new_request.extra_args = [
+        a for a in new_request.extra_args if not a.startswith('--gtest_filter')
+    ]
+    new_request.extra_args.append('--gtest_filter=%s' % ':'.join(tests))
+
+    # Remove the env setting for sharding.
+    sharding_settings = ['GTEST_SHARD_INDEX', 'GTEST_TOTAL_SHARDS']
+    new_request.env = [
+        e for e in new_request.env if e['key'] not in sharding_settings
+    ]
+
+    # Reset tags for searching and monitoring.
+    ref_name = swarming_util.GetTagValue(ref_request.tags, 'name')
+    new_request.tags = []
+    new_request.tags.append('purpose:deflake')
+    new_request.tags.append('ref_master:%s' % master_name)
+    new_request.tags.append('ref_buildername:%s' % builder_name)
+    new_request.tags.append('ref_buildnumber:%s' % build_number)
+    new_request.tags.append('ref_stepname:%s' % step_name)
+    new_request.tags.append('ref_task_id:%s' % ref_task_id)
+    new_request.tags.append('ref_name:%s' % ref_name)
+
+    return new_request
+
+  @ndb.transactional
+  def _GetSwarmingTask(self, master_name, builder_name,
+                       build_number, step_name):
+    # Get the appropriate kind of Swarming Task (Wf or Flake)
+    # Should be overwritten in child method
+    pass

[stgao, 2016/07/09 00:04:34]

Raise NotImplementedError ?

Same for below.

[caiw, 2016/07/14 00:59:45]

Done.

+
+  @ndb.transactional
+  def _CreateSwarmingTask(self, master_name, builder_name,
+                          build_number, step_name):
+    # Create the appropriate kind of Swarming Task (Wf or Flake)
+    # Should be overwritten in child method
+    pass
+
+  # pylint: disable=no-value-for-parameter
+  @ndb.transactional(xg=True)

[stgao, 2016/07/09 00:04:34]

Why cross-group transaction is needed here?

[caiw, 2016/07/14 00:59:45]

I don't remember, but I got an error requiring me to set this to true.  it might
be because of the relation between swarmingtask and master_flake_analysis?

+  def _NeedANewSwarmingTask(self, master_name, builder_name,
+                            build_number, step_name):
+    swarming_task = self._GetSwarmingTask(
+        master_name, builder_name, build_number, step_name)
+
+    if not swarming_task:
+      swarming_task = self._CreateSwarmingTask(
+          master_name, builder_name, step_name, build_number)
+      swarming_task.status = analysis_status.PENDING
+      swarming_task.put()
+      return True
+    else:
+      # TODO(http://crbug.com/585676): Rerun the Swarming task if it runs into
+      # unexpected infra errors.
+      return False
+
+
+  def _GetSwarmingTaskId(self, master_name, builder_name,
+                         build_number, step_name):
+    deadline = time.time() + 5 * 60  # Wait for 5 minutes.
+    while time.time() < deadline:
+      swarming_task = self._GetSwarmingTask(
+          master_name, builder_name, step_name, build_number)
+
+      if not swarming_task:  # pragma: no cover. Pipeline will retry.
+        raise Exception('Swarming task was deleted unexpectedly!!!')
+
+      if swarming_task.task_id:
+        return swarming_task.task_id
+
+      # Wait for the existing pipeline to start the Swarming task.
+      time.sleep(10)
+
+    raise Exception('Time out!')  # pragma: no cover. Pipeline will retry.
+
+  def _GetIterationsToRerun(self):
+    # How many times we want to run the swarming rerun
+    # By default, it's what's in wf_config
+    iterations_to_rerun = waterfall_config.GetSwarmingSettings().get(

[stgao, 2016/07/09 00:04:34]

Should this be implemented in the subclass instead?

[caiw, 2016/07/14 00:59:45]

Sure, that would be fine.

+        'iterations_to_rerun')
+    return iterations_to_rerun
+
+  # Arguments number differs from overridden method - pylint: disable=W0221
+  def run(self, master_name, builder_name, build_number, step_name, tests):
+    """Triggers a new Swarming task to run the given tests.
+
+    Args:
+      master_name (str): The master name.
+      builder_name (str): The builder name.
+      build_number (str): The build number.
+      step_name (str): The failed test step name.
+      tests (list): A list of test cases, eg: ['suite1.test1', 'suite2.test2'].
+
+    Returns:
+      task_id (str): The new Swarming task that re-run the given tests.
+    """
+    # Check if a new Swarming Task is really needed.
+    if not self._NeedANewSwarmingTask(
+        master_name, builder_name, build_number, step_name):
+      return self._GetSwarmingTaskId(
+          master_name, builder_name, build_number, step_name)
+
+    assert tests
+    http_client = HttpClient()
+
+    # 0. Retrieve existing Swarming task ids for the given step.
+    swarming_task_items = swarming_util.ListSwarmingTasksDataByTags(
+        master_name, builder_name, build_number, http_client, step_name)
+    assert len(swarming_task_items) > 0, 'No Swarming task was run.'
+    ref_task_id = swarming_task_items[0]['task_id']
+
+    # 1. Retrieve Swarming task parameters from a given Swarming task id.
+    ref_request = swarming_util.GetSwarmingTaskRequest(
+        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)
+
+    # Save the task id.
+    swarming_task = self._GetSwarmingTask(
+        master_name, builder_name, step_name, build_number)
+    swarming_task.task_id = task_id
+    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)
+    return task_id