display "latest GM failures" link in its own line under build step

master/skia_master_scripts/skia_build_step.py

 # Copyright (c) 2012 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.
 
 """ Skia-specific subclass of BuildStep """
 
 
 from buildbot.status.logfile import STDOUT
 from master.log_parser import retcode_command
 import re
 
 
 class SkiaBuildStep(retcode_command.ReturnCodeCommand):
   """ BuildStep wrapper for Skia. Allows us to define properties of BuildSteps
   to be used by ShouldDoStep. This is necessary because the properties referred
   to by BuildStep.getProperty() are scoped for the entire duration of the build.
   """
   def __init__(self, is_upload_step=False, is_rebaseline_step=False,
-               get_props_from_stdout=None, exception_on_failure=False,
-               **kwargs):
+               get_links_from_stdout=None, get_props_from_stdout=None,
+               exception_on_failure=False, **kwargs):
     """ Instantiates a new SkiaBuildStep.
 
     is_upload_step: boolean indicating whether this step should be skipped when
         the buildbot is not performing uploads.
     is_rebaseline_step: boolean indicating whether this step is required for
         rebaseline-only builds.
+    get_links_from_stdout: optional dictionary. Keys are strings indicating
+        link text to set based on the output of this step. Values are
+        strings containing regular expressions for parsing the linked URL from
+        the output of the step.
     get_props_from_stdout: optional dictionary. Keys are strings indicating
         build properties to set based on the output of this step. Values are
         strings containing regular expressions for parsing the property from
         the output of the step.
     exception_on_failure: boolean indicating whether to raise an exception if
         this step fails. This causes the step to go purple instead of red, and
         causes the build to stop. Should be used if the build step's failure is
         typically transient or results from an infrastructure failure rather
         than a code change.
     """
     self._is_upload_step = is_upload_step
     self._is_rebaseline_step = is_rebaseline_step
+    self._get_links_from_stdout = get_links_from_stdout
     self._get_props_from_stdout = get_props_from_stdout
     self._exception_on_failure = exception_on_failure
 
     # self._changed_props will be a dictionary containing the build properties
     # which were updated by this BuildStep. Those properties will be displayed
     # in the label for this step.
     self._changed_props = None
 
     retcode_command.ReturnCodeCommand.__init__(self, **kwargs)
     self.name = ''.join(self.description)
 
   def IsUploadStep(self):
     return self._is_upload_step
 
   def IsRebaselineStep(self):
     return self._is_rebaseline_step
 
   def commandComplete(self, cmd):
     """ Override of BuildStep's commandComplete method which allows us to parse
     build properties from the output of this step. """
 
-    # We make a best effort to parse the properties out of stdout, whether
-    # the command succeeded or failed.  If the command succeeded, we
-    # definitely expect the property to be found in stdout--if not, raise
-    # an exception.
-    if self._get_props_from_stdout:
+    if self._get_props_from_stdout or self._get_links_from_stdout:
       log = cmd.logs['stdio']
       stdout = ''.join(log.getChunks([STDOUT], onlyText=True))

[borenet, 2014/06/06 12:10:34]

This is probably a performance killer. Seems like it wouldn't be hard to rewrite
this, as long as we don't care about properties/links with multi-line regexp.

[epoger, 2014/06/09 13:33:29]

I don't know how the chunks are split.  It would not be ideal to sometimes miss
an item because it straddled the borderline between two chunks.

       self._changed_props = {}
-      for prop, regex in self._get_props_from_stdout.iteritems():
-        matches = re.search(regex, stdout)
-        if not matches:
-          if cmd.rc == 0:
-            raise Exception('Unable to parse %s from stdout.' % prop)
-          continue
-        groups = matches.groups()
-        if len(groups) != 1:
-          if cmd.rc == 0:
-            raise Exception('Multiple matches for "%s"' % regex)
-          continue
-        prop_value = groups[0]
-        self.setProperty(prop, prop_value, ''.join(self.description))
-        self._changed_props[prop] = prop_value
+
+      # We make a best effort to parse the properties out of stdout, whether
+      # the command succeeded or failed.  If the command succeeded, we
+      # definitely expect the property to be found in stdout--if not, raise
+      # an exception.
+      if self._get_props_from_stdout:
+        for prop, regex in self._get_props_from_stdout.iteritems():
+          matches = re.search(regex, stdout)
+          if not matches:
+            if cmd.rc == 0:
+              raise Exception('Unable to parse %s from stdout.' % prop)
+            continue
+          groups = matches.groups()
+          if len(groups) != 1:
+            if cmd.rc == 0:
+              raise Exception('Multiple matches for "%s"' % regex)
+            continue
+          prop_value = groups[0]
+          self.setProperty(prop, prop_value, ''.join(self.description))
+          self._changed_props[prop] = prop_value
+
+      # If there might be URL links we want in stdout, look for them;
+      # their presence is optional, though, so we don't throw an exception
+      # if they are not found.
+      if self._get_links_from_stdout:
+        for name, regex in self._get_links_from_stdout.iteritems():
+          matches = re.search(regex, stdout)
+          if matches:
+            groups = matches.groups()
+            for url in groups:
+              self.addURL(name, url)
 
     if (cmd.rc not in (0, retcode_command.ReturnCodeCommand.RETCODE_WARNINGS)
         and self._exception_on_failure):
       raise Exception('Command marked exception_on_failure failed.')
     retcode_command.ReturnCodeCommand.commandComplete(self, cmd)
 
   def getText(self, cmd, results):
     """ Override of BuildStep's getText method which appends any changed build
     properties to the description of the BuildStep. """
     text = self.description
@@ skipping 31 matching lines @@
   # If this step uploads results (and thus overwrites the most recently uploaded
   # results), only run it on scheduled builds (i.e. most recent revision) or if
   # the "force_upload" property was set.
   if step.IsUploadStep() and \
       not _HasProperty(step, 'scheduler') and \
       not _HasProperty(step, 'force_upload'):
     return False
 
   # Unless we have determined otherwise, run the step.
   return True