recipe engine: add remote_run command

recipe_engine/package.py

 # Copyright 2015 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 ast
 import collections
 import contextlib
 import copy
 import difflib
 import functools
 import itertools
 import logging
 import operator
 import os
 import subprocess
 import sys
 import tempfile
 
 from .third_party.google.protobuf import text_format
 from . import package_pb2
-
-
-class UncleanFilesystemError(Exception):
-  pass
-
-
-class FetchNotAllowedError(Exception):
-  pass
+from . import fetch
 
 
 class InconsistentDependencyGraphError(Exception):
   def __init__(self, project_id, specs):
     self.project_id = project_id
     self.specs = specs
 
   def __str__(self):
     return 'Package specs for %s do not match: %s vs %s' % (
         project_id, self.specs[0], self.specs[1])
 
 
 class CyclicDependencyError(Exception):
   pass
 
 
-def cleanup_pyc(path):
-  """Removes any .pyc files from |path|'s directory tree.
-  This ensures we always use the fresh code.
-  """
-  for root, dirs, files in os.walk(path):
-    for f in files:
-      if f.endswith('.pyc'):
-        os.unlink(os.path.join(root, f))
-
-
 class InfraRepoConfig(object):
   def to_recipes_cfg(self, repo_root):
     # TODO(luqui): This is not always correct.  It can be configured in
     # infra/config:refs.cfg.
     return os.path.join(repo_root, 'infra', 'config', 'recipes.cfg')
 
   def from_recipes_cfg(self, recipes_cfg):
     return os.path.dirname( # <repo root>
             os.path.dirname( # infra
               os.path.dirname( # config
@@ skipping 151 matching lines @@
   def run_git(self, context, *args):
     cmd = [self._git]
     if context is not None:
       cmd += ['-C', self._dep_dir(context)]
     cmd += list(args)
 
     logging.info('Running: %s', cmd)
     return subprocess.check_output(cmd)
 
   def checkout(self, context):
-    dep_dir = self._dep_dir(context)
-    logging.info('Freshening repository %s', dep_dir)
-
-    if not os.path.isdir(dep_dir):
-      if context.allow_fetch:
-        self.run_git(None, 'clone', '-q', self.repo, dep_dir)
-      else:
-        raise FetchNotAllowedError(
-            'need to clone %s but fetch not allowed' % self.repo)
-    elif not os.path.isdir(os.path.join(dep_dir, '.git')):
-      raise UncleanFilesystemError('%s exists but is not a git repo' % dep_dir)
-
-    try:
-      self.run_git(context, 'rev-parse', '-q', '--verify',
-                   '%s^{commit}' % self.revision)
-    except subprocess.CalledProcessError:
-      if context.allow_fetch:
-        self.run_git(context, 'fetch')
-      else:
-        raise FetchNotAllowedError(
-            'need to fetch %s but fetch not allowed' % self.repo)
-    self.run_git(context, 'reset', '-q', '--hard', self.revision)
-    cleanup_pyc(dep_dir)
+    fetch.fetch_from_git(
+        self.repo, self.revision, self._dep_dir(context), context.allow_fetch)
 
   def repo_root(self, context):
     return os.path.join(self._dep_dir(context), self.path)
 
   def dump(self):
     buf = package_pb2.DepSpec(
         project_id=self.project_id,
         url=self.repo,
         branch=self.branch,
         revision=self.revision)
@@ skipping 442 matching lines @@
   >>> d = { 'x': 1, 'y': 2 }
   >>> sorted(_updated(d, { 'y': 3, 'z': 4 }).items())
   [('x', 1), ('y', 3), ('z', 4)]
   >>> sorted(d.items())
   [('x', 1), ('y', 2)]
   """
 
   d = copy.copy(d)
   d.update(updates)
   return d