Android perf runner: print the command line in the step itself.

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 a perf test on a single device.
 
 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 54 matching lines @@
   Returns:
     exit code generated by the test step.
   """
   file_name = os.path.join(_OUTPUT_DIR, test_name)
   if not os.path.exists(file_name):
     logging.error('File not found %s', file_name)
     return 1
 
   with file(file_name, 'r') as f:
     persisted_result = pickle.loads(f.read())
+  print '*' * 80

[frankf, 2013/08/22 17:41:12]

why not logging?

[bulach, 2013/08/23 09:13:55]

done (the last one has to be print as it was, since it's parsed the buildbot).

+  print 'Output from:'
+  print persisted_result['cmd']
+  print '*' * 80
   print persisted_result['output']
 
   return persisted_result['exit_code']
 
 
 class TestRunner(base_test_runner.BaseTestRunner):
   def __init__(self, test_options, device, tests, flaky_tests):
     """A TestRunner instance runs a perf test on a single device.
 
     Args:
@@ skipping 17 matching lines @@
 
     Args:
       test_name: the name of the test to be executed.
 
     Returns:
       A tuple containing (Output, base_test_result.ResultType)
     """
     cmd = ('%s --device %s --keep_test_server_ports' %
            (self._tests[test_name], self.device))
     start_time = datetime.datetime.now()
     output, exit_code = pexpect.run(

[frankf, 2013/08/22 17:41:12]

BTW, have you seen any issue with pexpect terminating? I ran into an this issue
for another CL downstream and it seems like a bug in pexpect itself.

[bulach, 2013/08/23 09:13:55]

yeah, sometimes exit_code is None (as per the other patch)..
I hope this will help identify which step is happening...
tbh, the only reason for pexpect here is just so it can "stream" the output to
sys.stdout _and_ capture to save to the file...

if you have any other suggestions, I'd be more than happy to use it instead!! 

hmm... actually... maybe apply a file-like object and pass that to stdout param
on subprocess.Popen? let me try that, I think we used this trick somewhere
else...

[bulach, 2013/08/23 11:25:08]

for completeness: unfortunately subprocess.Popen doesn't take a "file-like"
object, it really needs a "file" that implements a fileno() with the underlying
FD so that the child process can write directly to, which makes sense...

so there's no easy way to "capture" the stdout whilst streaming it to sys.stdout
without, well, reimplementing this pexpect.run... :-/

anyways: once we know at least which step is failing, I hope it'll give more
insights.

         cmd, cwd=os.path.abspath(constants.DIR_SOURCE_ROOT),
         withexitstatus=True, logfile=sys.stdout, timeout=1800,
         env=os.environ)
     end_time = datetime.datetime.now()
     logging.info('%s : exit_code=%d in %d secs at %s',
                  test_name, exit_code, (end_time - start_time).seconds,
                  self.device)
     result_type = base_test_result.ResultType.FAIL
     if exit_code == 0:
       result_type = base_test_result.ResultType.PASS
     if test_name in self._flaky_tests:
       exit_code = 0
       result_type = base_test_result.ResultType.PASS
 
     persisted_result = {
         'name': test_name,
         'output': output,
         'exit_code': exit_code,
         'result_type': result_type,
         'total_time': (end_time - start_time).seconds,
         'device': self.device,
+        'cmd': cmd,
     }
     self._SaveResult(persisted_result)
 
     return (output, result_type)
 
   def RunTest(self, test_name):
     """Run a perf test on the device.
 
     Args:
       test_name: String to use for logging the test result.
 
     Returns:
       A tuple of (TestRunResults, retry).
     """
     output, 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