recipe engine: add remote_run command

recipes.py

Index: recipes.py
diff --git a/recipes.py b/recipes.py
index d5955f89cc27ac6458038fb937dbc9d06cbc4ef9..79dd237c85c9371e3cf7acb2457c2f172712e3d9 100755
--- a/recipes.py
+++ b/recipes.py
@@ -147,6 +147,12 @@ def run(package_deps, args):
   return handle_recipe_return(ret, args.output_result_json, stream_engine)
 
 
+def remote_run(args):
+  from recipe_engine import remote_run
+
+  return remote_run.main(args)
+
+
 def autoroll(args):
   from recipe_engine import autoroll
 
@@ -287,6 +293,23 @@ def main():
       help='A list of property pairs; e.g. mastername=chromium.linux '
            'issue=12345')
 
+  remote_run_p = subp.add_parser(
+      'remote_run',
+      description='Run a recipe from specified repo and revision')
+  remote_run_p.set_defaults(command='remote_run')
+  remote_run_p.add_argument(
+      '--repository', required=True,
+      help='URL of a git repository to fetch')
+  remote_run_p.add_argument(
+      '--revision', default='FETCH_HEAD',
+      help='Git commit hash to check out')
+  remote_run_p.add_argument(

[nodir, 2016/05/20 23:03:50]

since this is a long term solution, add --fetch-ref that defaults to
"refs/heads/master"

[Paweł Hajdan Jr., 2016/05/25 00:15:42]

What would be semantics of that? How about we only add it when we need it and
implement it?

Also, it's not obvious to me how it'd apply to gitiles fetch.

Overall, it's probably worthwhile to consider this but necessarily in scope of
this CL.

WDYT?

+      '--workdir',
+      help='The working directory of repo checkout')
+  remote_run_p.add_argument(
+      'run_args', nargs='*',
+      help='Arguments to pass to fetched repo\'s recipes.py run')
+
   autoroll_p = subp.add_parser(
       'autoroll',
       help='Roll dependencies of a recipe package forward (implies fetch)')
@@ -335,6 +358,11 @@ def main():
   if args.verbose:
     logging.getLogger().setLevel(logging.INFO)
 
+  # Commands which do not require config_file, package_deps, and other objects
+  # initialized later.
+  if args.command == 'remote_run':
+    return remote_run(args)
+
   repo_root, config_file = get_package_config(args)
 
   try: