Add step generator protocol, remove annotated_checkout, remove script.

scripts/common/annotator.py

 #!/usr/bin/env python
 # Copyright (c) 2013 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.
 
 """Contains generating and parsing systems of the Chromium Buildbot Annotator.
 
 When executed as a script, this reads step name / command pairs from a file and
 executes those lines while annotating the output. The input is json:
 
@@ skipping 343 matching lines @@
     cmd: command to run, list of one or more strings
     cwd: absolute path to working directory for the command
     env: dict with overrides for environment variables
     skip: True to skip this step
     always_run: True to run the step even if some previous step failed
     ignore_annotations: if True will ignore annotations emitted by the step
 
   Returns new value for build_failure.
   """
   if skip or (build_failure and not always_run):
-    return build_failure
+    return build_failure, None
 
   # For error reporting.
   step_dict = locals().copy()
   step_dict.pop('stream')
   step_dict.update(kwargs)
 
   filter_obj = None
   if ignore_annotations:
     class AnnotationFilter(chromium_utils.RunCommandFilter):
       def FilterLine(self, line):
         return line.replace('@@@', '###')
     filter_obj = AnnotationFilter()
 
+  ret = None
   try:
     with stream.step(name) as s:
       ret = chromium_utils.RunCommand(command=map(str, cmd),
                                       cwd=cwd,
                                       env=_merge_envs(os.environ, env),
                                       filter_obj=filter_obj)
       if ret != 0:
         print 'step returned non-zero exit code: %d' % ret
         print 'step was: %s' % json.dumps(step_dict)
         s.step_failure()
         build_failure = True
   except OSError:
     # File wasn't found, error has been already reported to stream.
     build_failure = True
 
-  return build_failure
+  return build_failure, ret
+
+
+def run_steps(steps, build_failure):
+  for step in steps:
+    error = _validate_step(step)
+    if error:
+      print 'Invalid step - %s\n%s' % (error, json.dumps(step, indent=2))
+      sys.exit(1)
+
+  seed_steps = []
+  for step in steps:
+    seed_steps.append(step['name'])
+    seed_steps.extend(step.get('seed_steps', []))
+
+  stream = StructuredAnnotationStream(seed_steps=seed_steps)
+  ret_codes = []
+  for step in steps:
+    build_failure, ret = _run_step(stream, build_failure, **step)
+    ret_codes.append(ret)
+  return build_failure, ret_codes
 
 
 def main():
   usage = '%s <command list file or - for stdin>' % sys.argv[0]
   parser = optparse.OptionParser(usage=usage)
   _, args = parser.parse_args()
   if not args:
     parser.error('Must specify an input filename.')
   if len(args) > 1:
     parser.error('Too many arguments specified.')
 
   steps = []
 
   if args[0] == '-':
     steps.extend(json.load(sys.stdin))
   else:
     with open(args[0], 'rb') as f:
       steps.extend(json.load(f))
 
-  for step in steps:
-    error = _validate_step(step)
-    if error:
-      print 'Invalid step - %s\n%s' % (error, json.dumps(step, indent=2))
-      return 1
-
-  stream = StructuredAnnotationStream(seed_steps=[s['name'] for s in steps])
-  build_failure = False
-  for step in steps:
-    build_failure = _run_step(stream, build_failure, **step)
-  return 1 if build_failure else 0
+  return 1 if run_steps(steps, False)[0] else 0
 
 
 if __name__ == '__main__':
   sys.exit(main())