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..6fed0a3f14f67ffb28811e5dbbf0876c59366130
--- /dev/null
+++ b/gm/rebaseline_server/download_actuals.py
@@ -0,0 +1,192 @@
+#!/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):

[rmistry, 2014/01/24 18:07:35]

I do not see this used in this module, it is here and not in the unittest
instead because you are anticipating some other callers using it?
In the future when you have a download_expectations you may need this similarly
and it may need to be moved to a utils module.

[epoger, 2014/01/24 18:23:50]

Yes. Added a comment along those lines.
Agreed.

+  """ Returns a file:/// URL pointing at the given filepath on local disk.
+
+  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)))
+

[rmistry, 2014/01/24 18:07:35]

nit: add an extra newline

[epoger, 2014/01/24 18:23:50]

Done.

+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)
+

[rmistry, 2014/01/24 18:07:35]

nit: add an extra newline

[epoger, 2014/01/24 18:23:50]

Done.

+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()