Add presubmit trybuilder to Luci-GAE repository.

scripts/slave/recipes/infra/luci_gae.py

Index: scripts/slave/recipes/infra/luci_gae.py
diff --git a/scripts/slave/recipes/infra/luci_gae.py b/scripts/slave/recipes/infra/luci_gae.py
index 3437a36b21f5caa425764e95aa0739b4c4560fe4..06e29556096034d160eb67f1501c1de74f0bca27 100644
--- a/scripts/slave/recipes/infra/luci_gae.py
+++ b/scripts/slave/recipes/infra/luci_gae.py
@@ -5,6 +5,8 @@
 DEPS = [
   'bot_update',
   'gclient',
+  'git',
+  'json',
   'path',
   'properties',
   'python',
@@ -12,6 +14,41 @@ DEPS = [
 ]
 
 
+def _run_presubmit(api, patch_root, bot_update_step):
+  upstream = bot_update_step.json.output['properties'].get(
+      api.gclient.c.got_revision_mapping[
+      'infra/go/src/github.com/luci/gae'])
+  # The presubmit must be run with proper Go environment.
+  # infra/go/env.py takes care of this.
+  presubmit_cmd = [
+    'python',  # env.py will replace with this its sys.executable.
+    api.path['depot_tools'].join('presubmit_support.py'),
+    '--root', api.path['slave_build'].join(patch_root),
+    '--commit',
+    '--verbose', '--verbose',
+    '--issue', api.properties['issue'],
+    '--patchset', api.properties['patchset'],
+    '--skip_canned', 'CheckRietveldTryJobExecution',
+    '--skip_canned', 'CheckTreeIsOpen',
+    '--skip_canned', 'CheckBuildbotPendingBuilds',
+    '--rietveld_url', api.properties['rietveld'],
+    '--rietveld_fetch',
+    '--upstream', upstream,
+    '--trybot-json', api.json.output(),
+    '--rietveld_email', ''
+  ]
+  api.python('presubmit', api.path['checkout'].join('go', 'env.py'),
+             presubmit_cmd, env={'PRESUBMIT_BUILDER': '1'})
+
+
+def _commit_change(api, patch_root):
+  api.git('-c', 'user.email=commit-bot@chromium.org',
+          '-c', 'user.name=The Commit Bot',
+          'commit', '-a', '-m', 'Committed patch',
+          name='commit git patch',
+          cwd=api.path['slave_build'].join(patch_root))
+
+
 def RunSteps(api):
   api.gclient.set_config('luci_gae')
   # patch_root must match the luci/gae repo, not infra checkout.
@@ -19,7 +56,12 @@ def RunSteps(api):
     if 'github.com/luci/gae' in path:
       patch_root = path
       break
-  api.bot_update.ensure_checkout(force=True, patch_root=patch_root)
+  bot_update_step = api.bot_update.ensure_checkout(force=True,
+                                                   patch_root=patch_root)
+
+  is_presubmit = 'presubmit' in api.properties.get('buildername', '').lower()
+  if is_presubmit:
+    _commit_change(api, patch_root)
   api.gclient.runhooks()
 
   # This downloads the third parties, so that the next step doesn't have junk
@@ -29,15 +71,19 @@ def RunSteps(api):
       api.path['checkout'].join('go', 'env.py'),
       ['go', 'version'])
 
-  api.python(
-      'go build',
-      api.path['checkout'].join('go', 'env.py'),
-      ['go', 'build', 'github.com/luci/gae/...'])
+  if is_presubmit:
+    with api.tryserver.set_failure_hash():
+      _run_presubmit(api, patch_root, bot_update_step)
+  else:
+    api.python(
+        'go build',
+        api.path['checkout'].join('go', 'env.py'),
+        ['go', 'build', 'github.com/luci/gae/...'])
 
-  api.python(
-      'go test',
-      api.path['checkout'].join('go', 'env.py'),
-      ['go', 'test', 'github.com/luci/gae/...'])
+    api.python(
+        'go test',
+        api.path['checkout'].join('go', 'env.py'),
+        ['go', 'test', 'github.com/luci/gae/...'])
 
 
 def GenTests(api):
@@ -45,8 +91,14 @@ def GenTests(api):
     api.test('luci_gae') +
     api.properties.git_scheduled(
         buildername='luci-gae-linux64',
-        buildnumber=123,
         mastername='chromium.infra',
         repository='https://chromium.googlesource.com/external/github.com/luci/gae',
     )
   )
+  yield (
+    api.test('presubmit_try_job') +
+    api.properties.tryserver(
+        mastername='tryserver.infra',
+        buildername='Luci-GAE Presubmit',
+    ) + api.step_data('presubmit', api.json.output([[]]))
+  )