Cross-repo recipe package system.

scripts/slave/recipes.py

Index: scripts/slave/recipes.py
diff --git a/scripts/slave/recipes.py b/scripts/slave/recipes.py
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+#!/usr/bin/env python
+
+# 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.
+
+"""Bootstrap script to clone and forward to the recipe engine tool."""
+
+import ast
+import logging
+import os
+import random
+import re
+import subprocess
+import sys
+import time
+import traceback
+
+BOOTSTRAP_VERSION = 1
+RECIPES_CFG = os.path.join(
+    os.pardir, os.pardir, 'infra', 'config', 'recipes.cfg')
+
+
+def parse_protobuf(fh):
+  """Parse the protobuf text format just well enough to understand recipes.cfg.
+
+  We don't use the protobuf library because we want to be as self-contained
+  as possible in this bootstrap, so it can be simply vendored into a client
+  repo.
+
+  We assume all fields are repeated since we don't have a proto spec to work
+  with.
+
+  Args:
+    fh: a filehandle containing the text format protobuf.
+  Returns:
+    A recursive dictionary of lists.
+  """
+  def parse_atom(text):
+    if text == 'true': return True
+    if text == 'false': return False
+    return ast.literal_eval(text)
+
+  ret = {}
+  for line in fh:
+    line = line.strip()
+    m = re.match(r'(\w+)\s*:\s*(.*)', line)
+    if m:
+      ret.setdefault(m.group(1), []).append(parse_atom(m.group(2)))
+      continue
+
+    m = re.match(r'(\w+)\s*{', line)
+    if m:
+      subparse = parse_protobuf(fh)
+      ret.setdefault(m.group(1), []).append(subparse)
+      continue
+
+    if line == '}': return ret
+    if line == '': continue
+
+    raise Exception('Could not understand line: <%s>' % line)
+
+  return ret
+
+
+def get_unique(things):
+  if len(things) == 1:
+    return things[0]
+  elif len(things) == 0:
+    raise ValueError("Expected to get one thing, but dinna get none.")
+  else:
+    logging.warn('Expected to get one thing, but got a bunch: %s\n%s' %
+                 (things, traceback.format_stack()))
+    return things[0]
+
+
+def main():
+  if sys.platform.startswith(('win', 'cygwin')):
+    git = 'git.bat'
+  else:
+    git = 'git'
+
+  # Find the repository and config file to operate on.
+  git_dir = os.path.dirname(
+    subprocess.check_output([git, 'rev-parse', '--git-dir'],
+    cwd=os.path.dirname(__file__)).strip())
+  recipes_cfg_path = os.path.join(os.path.dirname(__file__), RECIPES_CFG)
+
+  with open(recipes_cfg_path, 'rU') as fh:
+    protobuf = parse_protobuf(fh)
+
+  engine_buf = get_unique([
+      b for b in protobuf['deps'] if b.get('project_id') == ['recipe_engine'] ])
+  engine_url = get_unique(engine_buf['url'])
+  engine_revision = get_unique(engine_buf['revision'])
+  engine_subpath = (get_unique(engine_buf.get('path_override', ['']))
+                    .replace('/', os.path.sep))
+
+  recipes_path = os.path.join(git_dir,
+      get_unique(protobuf['recipes_path']).replace('/', os.path.sep))
+  deps_path = os.path.join(recipes_path, '.recipe_deps')
+  engine_path = os.path.join(deps_path, 'recipe_engine')
+
+  # Ensure that we have the recipe engine cloned.
+  def ensure_engine():
+    if not os.path.exists(deps_path):
+      os.makedirs(deps_path)
+    if not os.path.exists(engine_path):
+      subprocess.check_call([git, 'clone', engine_url, engine_path])
+
+    needs_fetch = subprocess.call(
+        [git, 'rev-parse', '--verify', '%s^{commit}' % engine_revision],
+        cwd=engine_path, stdout=open(os.devnull, 'w'))
+    if needs_fetch:
+      subprocess.check_call([git, 'fetch'], cwd=engine_path)
+    subprocess.check_call(
+        [git, 'checkout', '--quiet', engine_revision], cwd=engine_path)
+
+  try:
+    ensure_engine()
+  except subprocess.CalledProcessError as e:
+    if e.returncode == 128:  # Thrown when git gets a lock error.
+      time.sleep(random.uniform(2,5))
+      ensure_engine()
+    else:
+      raise
+
+  args = ['--package', recipes_cfg_path,
+          '--bootstrap-script', __file__] + sys.argv[1:]
+  return subprocess.call([
+      sys.executable, '-u',
+      os.path.join(engine_path, engine_subpath, 'recipes.py')] + args)
+
+if __name__ == '__main__':
+  sys.exit(main())