remote_run: Allow recipe engine pinning.

scripts/slave/remote_run.py

 #!/usr/bin/env python
 # 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 argparse
 import copy
 import json
 import logging
 import os
@@ skipping 14 matching lines @@
 from slave import infra_platform
 from slave import logdog_bootstrap
 from slave import monitoring_utils
 from slave import robust_tempdir
 from slave import update_scripts
 
 
 LOGGER = logging.getLogger('remote_run')
 
 
+# CIPD_PINS is a mapping of master name to pinned recipe engine CIPD package
+# version. If no pin is found, the CIPD pin for "None" will be used.
+_CIPD_PINS = {
+  # Default recipe engine pin.
+  None: 'latest',
+
+  # Custom per-master pins.
+  'chromium.infra': 'canary',
+}
+
+
 def _call(cmd, **kwargs):
   LOGGER.info('Executing command: %s', cmd)
   exit_code = subprocess.call(cmd, **kwargs)
   LOGGER.info('Command %s finished with exit code %d.', cmd, exit_code)
   return exit_code
 
 
 def _install_cipd_packages(path, *packages):
   """Bootstraps CIPD in |path| and installs requested |packages|.
 
@@ skipping 88 matching lines @@
           # confusing errors.
           for p in (os.path.join(buildbot_workdir, x)
                     for x in os.listdir(buildbot_workdir)):
             LOGGER.info('Deleting %r', p)
             chromium_utils.RemovePath(p)
       except Exception as e:
         # It's preferred that we keep going rather than fail the build
         # on optional cleanup.
         LOGGER.exception('Buildbot workdir cleanup failed: %s', e)
 
+    # Should we use a CIPD pin?
+    mastername = properties.get('mastername')
+    cipd_pin = None
+    if mastername:
+      cipd_pin = _CIPD_PINS.get(mastername)
+    if not cipd_pin:
+      cipd_pin = _CIPD_PINS[None]
+
     cipd_path = os.path.join(basedir, '.remote_run_cipd')
     _install_cipd_packages(
-        cipd_path, cipd.CipdPackage('infra/recipes-py', 'latest'))
+        cipd_path, cipd.CipdPackage('infra/recipes-py', cipd_pin))
 
     recipe_result_path = os.path.join(tempdir, 'recipe_result.json')
     recipe_cmd = [
         sys.executable,
         os.path.join(cipd_path, 'recipes.py'),
         '--verbose',
         'remote',
         '--repository', args.repository,
         '--revision', args.revision,
         '--workdir', os.path.join(tempdir, 'rw'),
@@ skipping 42 matching lines @@
     # Re-execute with the updated remote_run.py.
     return _call([sys.executable] + argv)
 
   stream = annotator.StructuredAnnotationStream()
   with stream.step('remote_run_result'):
     return main(argv)
 
 
 if __name__ == '__main__':
   sys.exit(shell_main(sys.argv))