[Android] Ensure perf test runner does not create shards for blacklisted devices.

build/android/pylib/base/test_dispatcher.py

Index: build/android/pylib/base/test_dispatcher.py
diff --git a/build/android/pylib/base/test_dispatcher.py b/build/android/pylib/base/test_dispatcher.py
index c513d9abebf9fe9336a18eb3b771b6fa422cc8c4..c11d52e8b39e7738115586ee8611478e76d4d773 100644
--- a/build/android/pylib/base/test_dispatcher.py
+++ b/build/android/pylib/base/test_dispatcher.py
@@ -21,6 +21,7 @@ Performs the following steps:
 import logging
 import threading
 
+from devil.android import device_blacklist
 from devil.android import device_errors
 from devil.utils import reraiser_thread
 from devil.utils import watchdog_timer
@@ -130,7 +131,8 @@ def _RunTestsFromQueue(runner, collection, out_results, watcher,
       collection.test_completed()
 
 
-def _SetUp(runner_factory, device, out_runners, threadsafe_counter):
+def _SetUp(runner_factory, device, out_runners, threadsafe_counter,
+           blacklist_file=None):
   """Creates a test runner for each device and calls SetUp() in parallel.
 
   Note: if a device is unresponsive the corresponding TestRunner will not be
@@ -142,10 +144,20 @@ def _SetUp(runner_factory, device, out_runners, threadsafe_counter):
     device: The device serial number to set up.
     out_runners: List to add the successfully set up TestRunner object.
     threadsafe_counter: A _ThreadSafeCounter object used to get shard indices.
+    blacklist_file: Path to device blacklist.
   """
   try:
     index = threadsafe_counter.GetAndIncrement()
     logging.warning('Creating shard %s for device %s.', index, device)
+
+    blacklist = (device_blacklist.Blacklist(blacklist_file).Read()

[jbudorick, 2016/06/06 22:52:27]

This isn't the right place to do this; it'll get read on all threads. This
should instead be handled in pylib.perf.setup.Setup, inside the
TestRunnerFactory it returns. I think you can do it by checking if the device is
in active_devices.

[rnephew (Reviews Here), 2016/06/06 23:33:21]

Yeah, that makes for a much much simpler solution.

+                 if blacklist_file
+                 else None)
+    if blacklist and str(device) in blacklist:
+      logging.info('Device %s is in blacklist. Not creating shard %s',
+                   str(device), index)
+      return
+
     runner = runner_factory(device, index)
     runner.SetUp()
     out_runners.append(runner)
@@ -214,7 +226,7 @@ def _RunAllTests(runners, test_collection_factory, num_retries, timeout=None,
   return (run_results, exit_code)
 
 
-def _CreateRunners(runner_factory, devices, timeout=None):
+def _CreateRunners(runner_factory, devices, timeout=None, blacklist_file=None):
   """Creates a test runner for each device and calls SetUp() in parallel.
 
   Note: if a device is unresponsive the corresponding TestRunner will not be
@@ -225,6 +237,7 @@ def _CreateRunners(runner_factory, devices, timeout=None):
       TestRunner object.
     devices: List of device serial numbers as strings.
     timeout: Watchdog timeout in seconds, defaults to the default timeout.
+    blacklist_file: Path to device blacklist file.
 
   Returns:
     A list of TestRunner objects.
@@ -235,7 +248,8 @@ def _CreateRunners(runner_factory, devices, timeout=None):
   counter = _ThreadSafeCounter()
   threads = reraiser_thread.ReraiserThreadGroup(
       [reraiser_thread.ReraiserThread(_SetUp,
-                                      [runner_factory, d, runners, counter],
+                                      [runner_factory, d, runners, counter,
+                                       blacklist_file],
                                       name=str(d)[-4:])
        for d in devices])
   threads.StartAll()
@@ -281,7 +295,7 @@ def ApplyMaxPerRun(tests, max_per_run):
 
 def RunTests(tests, runner_factory, devices, shard=True,
              test_timeout=DEFAULT_TIMEOUT, setup_timeout=DEFAULT_TIMEOUT,
-             num_retries=2, max_per_run=256):
+             num_retries=2, max_per_run=256, blacklist_file=None):
   """Run all tests on attached devices, retrying tests that don't pass.
 
   Args:
@@ -299,6 +313,7 @@ def RunTests(tests, runner_factory, devices, shard=True,
         test runners.
     num_retries: Number of retries for a test.
     max_per_run: Maximum number of tests to run in any group.
+    blacklist_file: Path to blacklist file.
 
   Returns:
     A tuple of (base_test_result.TestRunResults object, exit code).
@@ -326,7 +341,8 @@ def RunTests(tests, runner_factory, devices, shard=True,
 
   logging.info('Will run %d tests (%s): %s',
                len(tests_expanded), log_string, str(tests_expanded))
-  runners = _CreateRunners(runner_factory, devices, setup_timeout)
+  runners = _CreateRunners(runner_factory, devices, setup_timeout,
+                           blacklist_file=blacklist_file)
   try:
     return _RunAllTests(runners, test_collection_factory,
                         num_retries, test_timeout, tag_results_with_device)