Catch IOError when reading chartjson results in test_runner.py

build/android/pylib/perf/test_runner.py

 # Copyright 2013 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.
 
 """Runs perf tests.
 
 Our buildbot infrastructure requires each slave to run steps serially.
 This is sub-optimal for android, where these steps can run independently on
 multiple connected devices.
 
@@ skipping 215 matching lines @@
   def _CleanupOutputDirectory(self):
     if self._output_dir:
       shutil.rmtree(self._output_dir, ignore_errors=True)
       self._output_dir = None
 
   def _ReadChartjsonOutput(self):
     if not self._output_dir:
       return ''
 
     json_output_path = os.path.join(self._output_dir, 'results-chart.json')
-    with open(json_output_path) as f:
-      return f.read()
+    try:
+      with open(json_output_path) as f:
+        return f.read()
+    except IOError, e:
+      logging.error('Exception when reading chartjson: %s', e)

[jbudorick, 2015/06/09 19:54:17]

logging.exception

+      logging.error('This usually means that telemetry did not run, so it could'
+                    ' not generate the file. Please check the device running'
+                    ' the test.')
+      return ''
 
   def _LaunchPerfTest(self, test_name):
     """Runs a perf test.
 
     Args:
       test_name: the name of the test to be executed.
 
     Returns:
       A tuple containing (Output, base_test_result.ResultType)
     """
@@ skipping 100 matching lines @@
     Returns:
       A tuple of (TestRunResults, retry).
     """
     _, result_type = self._LaunchPerfTest(test_name)
     results = base_test_result.TestRunResults()
     results.AddResult(base_test_result.BaseTestResult(test_name, result_type))
     retry = None
     if not results.DidRunPass():
       retry = test_name
     return results, retry