Add support for swarming priority and expiration in the test spec

scripts/slave/recipe_modules/swarming/example.py

 # Copyright 2014 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.
 
 DEPS = [
   'file',
   'isolate',
   'recipe_engine/path',
   'recipe_engine/properties',
   'recipe_engine/python',
@@ skipping 47 matching lines @@
   try:
     api.swarming.default_env['invalid'] = 'foo'
   except TypeError:
     pass
 
   # Create a temp dir to put *.isolated files into.
   temp_dir = api.path.mkdtemp('hello_isolated_world')
 
   # Prepare a bunch of swarming tasks to run hello_world on multiple platforms.
   tasks = []
+  platform_priority_adjustment = {'win': '125', 'linux': 'max', 'mac': None}
   for platform in ('win', 'linux', 'mac'):
     # Isolate example hello_world.isolate from swarming client repo.
     # TODO(vadimsh): Add a thin wrapper around isolate.py to 'isolate' module?
     step_result = api.python(
         'archive for %s' % platform,
         api.swarming_client.path.join('isolate.py'),
         [
           'archive',
           '--isolate', api.swarming_client.path.join(
               'example', 'payload', 'hello_world.isolate'),
           '--isolated', temp_dir.join('hello_world.isolated'),
           '--isolate-server', api.isolate.isolate_server,
           '--config-variable', 'OS', platform,
           '--verbose',
         ], stdout=api.raw_io.output())
     # TODO(vadimsh): Pass result from isolate.py though --output-json option.
     isolated_hash = step_result.stdout.split()[0].strip()
 
     # Create a task to run the isolated file on swarming, set OS dimension.
     # Also generate code coverage for multi-shard case by triggering multiple
     # shards on Linux.
     task = api.swarming.task('hello_world', isolated_hash,
                              task_output_dir=temp_dir.join('task_output_dir'))
     task.dimensions['os'] = api.swarming.prefered_os_dimension(platform)
     task.shards = 2 if platform == 'linux' else 1
     task.tags.add('os:' + platform)
+    task.priority = api.swarming.parse_priority_adjustment(
+        platform_priority_adjustment[platform]) or api.swarming.default_priority
     tasks.append(task)
 
   # Launch all tasks.
   for task in tasks:
     step_result = api.swarming.trigger_task(task)
     assert step_result.swarming_task in tasks
 
   # Recipe can do something useful here locally while tasks are
   # running on swarming.
   api.step('local step', ['echo', 'running something locally'])
@@ skipping 70 matching lines @@
           stdout=api.raw_io.output('hash_for_linux hello_world.isolated')) +
       api.step_data(
           'archive for mac',
           stdout=api.raw_io.output('hash_for_mac hello_world.isolated')) +
       api.properties(
           rietveld="https://codereview.chromium.org",
           issue="123",
           patchset="1001",
           simulated_version=(0, 5),
           show_isolated_out_in_collect_step=False))