new tool: download all GM images for a given builder, ready for skdiff

gm/rebaseline_server/download_actuals.py

Index: gm/rebaseline_server/download_actuals.py
diff --git a/gm/rebaseline_server/download_actuals.py b/gm/rebaseline_server/download_actuals.py
new file mode 100755
index 0000000000000000000000000000000000000000..3f3f640f1216a1a5b041d809a8f316e6e11bec3a
--- /dev/null
+++ b/gm/rebaseline_server/download_actuals.py
@@ -0,0 +1,201 @@
+#!/usr/bin/python
+
+"""
+Copyright 2014 Google Inc.
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+
+Download actual GM results for a particular builder.
+"""
+
+# System-level imports
+import contextlib
+import optparse
+import os
+import posixpath
+import re
+import shutil
+import sys
+import urllib
+import urllib2
+import urlparse
+
+# Imports from within Skia
+#
+# We need to add the 'gm' and 'tools' directories, so that we can import
+# gm_json.py and buildbot_globals.py.
+#
+# Make sure that these dirs are in the PYTHONPATH, but add them at the *end*
+# so any dirs that are already in the PYTHONPATH will be preferred.
+#
+# TODO(epoger): Is it OK for this to depend on the 'tools' dir, given that
+# the tools dir is dependent on the 'gm' dir (to import gm_json.py)?
+TRUNK_DIRECTORY = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
+GM_DIRECTORY = os.path.join(TRUNK_DIRECTORY, 'gm')
+TOOLS_DIRECTORY = os.path.join(TRUNK_DIRECTORY, 'tools')
+if GM_DIRECTORY not in sys.path:
+  sys.path.append(GM_DIRECTORY)
+if TOOLS_DIRECTORY not in sys.path:
+  sys.path.append(TOOLS_DIRECTORY)
+import buildbot_globals
+import gm_json
+
+DEFAULT_ACTUALS_BASE_URL = posixpath.join(
+    buildbot_globals.Get('autogen_svn_url'), 'gm-actual')
+DEFAULT_JSON_FILENAME = 'actual-results.json'
+
+
+class Download(object):
+
+  def __init__(self, actuals_base_url=DEFAULT_ACTUALS_BASE_URL,
+               json_filename=DEFAULT_JSON_FILENAME,
+               gm_actuals_root_url=gm_json.GM_ACTUALS_ROOT_HTTP_URL):
+    """
+    Args:
+      actuals_base_url: URL pointing at the root directory
+          containing all actual-results.json files, e.g.,
+          http://domain.name/path/to/dir  OR
+          file:///absolute/path/to/localdir
+      json_filename: The JSON filename to read from within each directory.
+      gm_actuals_root_url: Base URL under which the actually-generated-by-bots
+          GM images are stored.
+    """
+    self._actuals_base_url = actuals_base_url
+    self._json_filename = json_filename
+    self._gm_actuals_root_url = gm_actuals_root_url
+    self._image_filename_re = re.compile(gm_json.IMAGE_FILENAME_PATTERN)
+
+  def fetch(self, builder_name, dest_dir):
+    """ Downloads actual GM results for a particular builder.
+
+    Args:
+      builder_name: which builder to download results of
+      dest_dir: path to directory where the image files will be written;
+                if the directory does not exist yet, it will be created
+
+    TODO(epoger): Display progress info.  Right now, it can take a long time
+    to download all of the results, and there is no indication of progress.
+
+    TODO(epoger): Download multiple images in parallel to speed things up.
+    """
+    json_url = posixpath.join(self._actuals_base_url, builder_name,
+                              self._json_filename)
+    json_contents = urllib2.urlopen(json_url).read()
+    results_dict = gm_json.LoadFromString(json_contents)
+
+    actual_results_dict = results_dict[gm_json.JSONKEY_ACTUALRESULTS]
+    for result_type in sorted(actual_results_dict.keys()):
+      results_of_this_type = actual_results_dict[result_type]
+      if not results_of_this_type:
+        continue
+      for image_name in sorted(results_of_this_type.keys()):
+        (test, config) = self._image_filename_re.match(image_name).groups()
+        (hash_type, hash_digest) = results_of_this_type[image_name]
+        source_url = gm_json.CreateGmActualUrl(
+            test_name=test, hash_type=hash_type, hash_digest=hash_digest,
+            gm_actuals_root_url=self._gm_actuals_root_url)
+        dest_path = os.path.join(dest_dir, config, test + '.png')
+        copy_contents(source_url=source_url, dest_path=dest_path,
+                      create_subdirs_if_needed=True)
+
+
+def create_filepath_url(filepath):
+  """ Returns a file:/// URL pointing at the given filepath on local disk.
+
+  For now, this is only used by unittests, but I anticipate it being useful
+  in production, as a way for developers to run rebaseline_server over locally
+  generated images.
+
+  TODO(epoger): Move this function, and copy_contents(), into a shared
+  utility module.  They are generally useful.
+
+  Args:
+    filepath: string; path to a file on local disk (may be absolute or relative,
+        and the file does not need to exist)
+
+  Returns:
+    A file:/// URL pointing at the file.  Regardless of whether filepath was
+        specified as a relative or absolute path, the URL will contain an
+        absolute path to the file.
+
+  Raises:
+    An Exception, if filepath is already a URL.
+  """
+  if urlparse.urlparse(filepath).scheme:
+    raise Exception('"%s" is already a URL' % filepath)
+  return urlparse.urljoin(
+      'file:', urllib.pathname2url(os.path.abspath(filepath)))
+
+
+def copy_contents(source_url, dest_path, create_subdirs_if_needed=False):
+  """ Copies the full contents of the URL 'source_url' into
+  filepath 'dest_path'.
+
+  Args:
+    source_url: string; complete URL to read from
+    dest_path: string; complete filepath to write to (may be absolute or
+        relative)
+    create_subdirs_if_needed: boolean; whether to create subdirectories as
+        needed to create dest_path
+
+  Raises:
+    Some subclass of Exception if unable to read source_url or write dest_path.
+  """
+  if create_subdirs_if_needed:
+    dest_dir = os.path.dirname(dest_path)
+    if not os.path.exists(dest_dir):
+      os.makedirs(dest_dir)
+  with contextlib.closing(urllib.urlopen(source_url)) as source_handle:
+    with open(dest_path, 'wb') as dest_handle:
+      shutil.copyfileobj(fsrc=source_handle, fdst=dest_handle)
+
+
+def main():
+  parser = optparse.OptionParser()
+  required_params = []
+  parser.add_option('--actuals-base-url',
+                    action='store', type='string',
+                    default=DEFAULT_ACTUALS_BASE_URL,
+                    help=('Base URL from which to read files containing JSON '
+                          'summaries of actual GM results; defaults to '
+                          '"%default". To get a specific revision (useful for '
+                          'trybots) replace "svn" with "svn-history/r123".'))
+  # TODO(epoger): Rather than telling the user to run "svn ls" to get the list
+  # of builders, add a --list-builders option that will print the list.
+  required_params.append('builder')
+  parser.add_option('--builder',
+                    action='store', type='string',
+                    help=('REQUIRED: Which builder to download results for. '
+                          'To see a list of builders, run "svn ls %s".' %
+                          DEFAULT_ACTUALS_BASE_URL))
+  required_params.append('dest_dir')
+  parser.add_option('--dest-dir',
+                    action='store', type='string',
+                    help=('REQUIRED: Directory where all images should be '
+                          'written. If this directory does not exist yet, it '
+                          'will be created.'))
+  parser.add_option('--json-filename',
+                    action='store', type='string',
+                    default=DEFAULT_JSON_FILENAME,
+                    help=('JSON summary filename to read for each builder; '
+                          'defaults to "%default".'))
+  (params, remaining_args) = parser.parse_args()
+
+  # Make sure all required options were set,
+  # and that there were no items left over in the command line.
+  for required_param in required_params:
+    if not getattr(params, required_param):
+      raise Exception('required option \'%s\' was not set' % required_param)
+  if len(remaining_args) is not 0:
+    raise Exception('extra items specified in the command line: %s' %
+                    remaining_args)
+
+  downloader = Download(actuals_base_url=params.actuals_base_url)
+  downloader.fetch(builder_name=params.builder,
+                   dest_dir=params.dest_dir)
+
+
+
+if __name__ == '__main__':
+  main()