Adding shard as a tag to perf swarming devices.

This is needed for soft device affinity so we have a way to know
which bot each shard ran on last.

Bug: 831252
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel
Change-Id: Idfde1b5f85816fdc9f496de2e9bbac4ef8298693
Reviewed-on: https://chromium-review.googlesource.com/1005721
Commit-Queue: Emily Hanley <eyaich@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#549929}

testing/trigger_scripts/base_test_triggerer.py

@@ -91,12 +91,13 @@ class BaseTestTriggerer(object):
       additional_args = all_args[:dash_ind] + bot_args + all_args[dash_ind:]
     else:
       additional_args = all_args + bot_args
-    return self.append_additional_args(additional_args)
+    return self.append_additional_args(additional_args, shard_index)
 
-  def append_additional_args(self, args):
+  def append_additional_args(self, args, shard_index):
     """ Gives subclasses ability to append additional args if necessary
 
-    Base class just returns given get."""
+    Base class just returns given args."""
+    del shard_index # unused
     return args
 
   def parse_bot_configs(self, args):

testing/trigger_scripts/perf_device_trigger.py

@@ -40,8 +40,18 @@ class PerfDeviceTriggerer(base_test_triggerer.BaseTestTriggerer):
   def __init__(self):
     super(PerfDeviceTriggerer, self).__init__()
 
-  def append_additional_args(self, args):
-    return args
+  def append_additional_args(self, args, shard_index):
+    # Append a tag to the swarming task with the shard number
+    # so we can query for the last bot that ran a specific shard.
+    tag = 'shard:%d' % shard_index
+    shard_tag = ['--tag', tag]
+    # Need to append this before the dash if present so it gets fed to
+    # the swarming task itself.
+    if '--' in args:
+      dash_ind = args.index('--')
+      return args[:dash_ind] + shard_tag + args[dash_ind:]
+    else:
+      return args + shard_tag
 
   def select_config_indices(self, args, verbose):
     # For perf we want to trigger a job for every valid config since

testing/trigger_scripts/perf_device_trigger_unittest.py

@@ -120,9 +120,13 @@ class UnitTest(unittest.TestCase):
   def test_shard_env_vars_and_bot_id(self):
     triggerer = self.basic_setup()
     self.assertTrue(self.list_contains_sublist(
-      triggerer._swarming_runs[0], ['--bot', 'build1']))
+      triggerer._swarming_runs[0], ['id', 'build1']))
     self.assertTrue(self.list_contains_sublist(
-      triggerer._swarming_runs[1], ['--bot', 'build2']))
+      triggerer._swarming_runs[1], ['id', 'build2']))
+    self.assertTrue(self.list_contains_sublist(
+      triggerer._swarming_runs[0], ['--tag', 'shard:0']))
+    self.assertTrue(self.list_contains_sublist(
+      triggerer._swarming_runs[1], ['--tag', 'shard:1']))
     self.assertTrue(self.list_contains_sublist(
       triggerer._swarming_runs[0], ['--env', 'GTEST_SHARD_INDEX', '0']))
     self.assertTrue(self.list_contains_sublist(