[telemetry] DO NOT SUBMIT: WIP: Helper modules for querying buildbot perf data.

tools/perf/dashboard/download.py

+#!/usr/bin/env python
+
+import logging
+import multiprocessing
+import sys
+import time
+import traceback
+
+import buildbot
+
+
+POLL_INTERVAL = 600
+BUILD_HISTORY_COUNT = 200
+BUILD_RESULTS_COUNT = 50
+
+
+def FetchLatestBuildResults(builder):
+  try:
+    builder.FetchRecentBuilds(BUILD_HISTORY_COUNT)
+    print 'Fetching results for', builder
+    for build in builder.LastBuilds(BUILD_RESULTS_COUNT):
+      for step in build.steps.itervalues():
+        step.results  # pylint: disable=pointless-statement
+  except:  # multiprocessing doesn't give useful stack traces, so print it here.
+    traceback.print_exc(file=sys.stderr)
+    print
+    raise
+
+
+def main():
+  logging.getLogger().setLevel(logging.INFO)
+  builders = buildbot.Builders('chromium.perf')
+
+  process_pool = multiprocessing.Pool(4)
+
+  while True:
+    print 'Refreshing...'
+    buildbot.Update('chromium.perf', builders)
+    process_pool.map(FetchLatestBuildResults, builders.itervalues())
+    print 'Refreshed!'
+    time.sleep(POLL_INTERVAL)
+
+
+if __name__ == '__main__':
+  main()