Add infra recipe module, use for updating Go DEPS

infra/bots/recipes/swarm_infra.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.
 
 
 # Recipe which runs the Skia infra tests.
 
 
 DEPS = [
   'core',
+  'infra',
   'recipe_engine/path',
   'recipe_engine/properties',
   'recipe_engine/step',
+  'run',
   'vars',
 ]
 
 
-UPDATE_GO_ATTEMPTS = 5
-
-
 def RunSteps(api):
   api.vars.setup()
   api.core.checkout_steps()
-
-  # Attempt to update go dependencies. This fails flakily sometimes, so perform
-  # multiple attempts.
-  gopath = api.vars.checkout_root.join('gopath')
-  env = {'GOPATH': gopath}
-  name = 'update go pkgs'
-  for attempt in xrange(UPDATE_GO_ATTEMPTS):
-    step_name = name
-    if attempt > 0:
-      step_name += ' (attempt %d)' % (attempt + 1)
-    try:
-      api.step(step_name,
-               cmd=['go', 'get', '-u', 'go.skia.org/infra/...'],
-               env=env)
-      break
-    except api.step.StepFailure:
-      if attempt == UPDATE_GO_ATTEMPTS - 1:
-        raise
+  api.infra.update_go_deps()
 
   # Run the infra tests.
   infra_tests = api.vars.skia_dir.join(
       'infra', 'bots', 'infra_tests.py')
   api.step('infra_tests',
            cmd=['python', infra_tests],
            cwd=api.vars.skia_dir,
-           env=env)
+           env=api.infra.go_env)
 
 
 def GenTests(api):
   yield (
       api.test('infra_tests') +
       api.properties(buildername='Housekeeper-PerCommit-InfraTests',
                      mastername='client.skia.fyi',
                      slavename='dummy-slave',
                      buildnumber=5,
                      revision='abc123',
@@ skipping 21 matching lines @@
                      buildnumber=5,
                      revision='abc123',
                      path_config='kitchen',
                      swarm_out_dir='[SWARM_OUT_DIR]') +
     api.step_data('update go pkgs', retcode=1) +
     api.step_data('update go pkgs (attempt 2)', retcode=1) +
     api.step_data('update go pkgs (attempt 3)', retcode=1) +
     api.step_data('update go pkgs (attempt 4)', retcode=1) +
     api.step_data('update go pkgs (attempt 5)', retcode=1)
   )