[tools/perf] Skip try job run if trybot config file does not change

tools/perf/core/trybot_command.py

Index: tools/perf/core/trybot_command.py
diff --git a/tools/perf/core/trybot_command.py b/tools/perf/core/trybot_command.py
index 8d145f0c7d2453a8e3a41ab49f2016ce9a85d7d8..87699398292f4d280da67871a6db846f99e001c7 100644
--- a/tools/perf/core/trybot_command.py
+++ b/tools/perf/core/trybot_command.py
@@ -244,14 +244,19 @@ class Trybot(command_line.ArgParseCommand):
           url if success, otherwise throws TrybotError exception.
     """
     config = self._GetPerfConfig(bot_platform, arguments)
+    config_to_write = 'config = %s' % json.dumps(
+        config, sort_keys=True, indent=2, separators=(',', ': '))
+
     try:
-      config_file = open(cfg_file_path, 'w')
+      with open(cfg_file_path, 'r') as config_file:
+        if config_to_write == config_file.read():
+          return NO_CHANGES, ''
     except IOError:
       msg = 'Cannot find %s. Please run from src dir.' % cfg_file_path
       return (ERROR, msg)
-    config_file.write('config = %s' % json.dumps(
-        config, sort_keys=True, indent=2, separators=(',', ': ')))
-    config_file.close()
+
+    with open(cfg_file_path, 'w') as config_file:
+      config_file.write(config_to_write)
     # Commit the config changes locally.
     returncode, out, err = _RunProcess(
         ['git', 'commit', '-a', '-m', 'bisect config: %s' % bot_platform])
@@ -394,8 +399,12 @@ class Trybot(command_line.ArgParseCommand):
           if results == ERROR:
             logging.error(output)
             return ERROR
-          print ('Uploaded %s try job to rietveld for %s platform. '
-                 'View progress at %s' % (source_repo, bot_platform, output))
+          elif results == NO_CHANGES:
+            print ('Skip the try job run on %s because it has been tried in '
+                   'previous try job run. ' % bot_platform)
+          else:

[sullivan, 2016/03/03 06:31:59]

Shouldn't this use logging api?

[nednguyen, 2016/03/03 06:52:23]

I am unsure with logging to use, error, warning & debug don't seem right. I
think it's ok to surface this kind of info to the users, hence we use print
here.

+            print ('Uploaded %s try job to rietveld for %s platform. '
+                   'View progress at %s' % (source_repo, bot_platform, output))
         except TrybotError, err:
           print err
           logging.error(err)