commit 0adaf115bb1229fbc2ff81f8c2872eceaaeeb5f5
author Chinglin Yu <chinglinyu@chromium.org> Mon Jan 20 14:48:20 2020 +0800
committer Commit Bot <commit-bot@chromium.org> Mon Jan 20 13:41:42 2020 +0000
tree f869b30647feb9b53c8b95668606bf77f54798dd
parent 755439486e845681a1ac64132ffe0536e344cb14

autotest: fix race condition in fetching telemetry dependencies.

telemetry_runner.py uses fixed output path for the output of fetching
dependency. This results in intermittent failures when multiple
telemetry tests run on the same machine. Fix the race condition by using
temp files for dependency output.

BUG=chromium:1043063
TEST=test_that --board=coral $dut --autotest_dir $AUTOTEST_DIR
--args=local=True telemetry_Benchmarks.tab_switching.typical_25

Change-Id: Ib21429fa8f5b0ef7fb66a0124e5d1f3614a576f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2008911
Commit-Queue: Chinglin Yu <chinglinyu@chromium.org>
Tested-by: Chinglin Yu <chinglinyu@chromium.org>
Reviewed-by: Chung-yih Wang <cywang@chromium.org>

server/cros/telemetry_runner.py

diff --git a/server/cros/telemetry_runner.py b/server/cros/telemetry_runner.py
index 3f412a7..ef32789 100644
--- a/server/cros/telemetry_runner.py
+++ b/server/cros/telemetry_runner.py
@@ -7,6 +7,7 @@
 import numbers
 import numpy
 import os
+import tempfile
 import StringIO
 
 from autotest_lib.client.common_lib import error, utils
@@ -110,6 +111,7 @@
             self._setup_local_telemetry()
         else:
             self._setup_devserver_telemetry()
+        self._benchmark_deps = None
 
         logging.debug('Telemetry Path: %s', self._telemetry_path)
 
@@ -465,9 +467,14 @@
         # Get DEPs using host's telemetry.
         # Example output, fetch_benchmark_deps.py --output-deps=deps octane:
         # {'octane': ['tools/perf/page_sets/data/octane_002.wprgo']}
-        perf_path = os.path.join(self._telemetry_path, 'tools', 'perf')
-        deps_path = os.path.join(perf_path, 'fetch_benchmark_deps_result.json')
-        fetch_path = os.path.join(perf_path, 'fetch_benchmark_deps.py')
+        fetch_path = os.path.join(self._telemetry_path,
+                                  'tools', 'perf', 'fetch_benchmark_deps.py')
+        # Use a temporary file for |deps_path| to avoid race conditions. The
+        # created temporary file is assigned to |self._benchmark_deps| to make
+        # it valid until |self| is destroyed.
+        self._benchmark_deps = tempfile.NamedTemporaryFile(
+            prefix='fetch_benchmark_deps_result.', suffix='.json')
+        deps_path = self._benchmark_deps.name
         format_fetch = ('python2 %s --output-deps=%s %s')
         command_fetch = format_fetch % (fetch_path, deps_path, test_name)
         command_get = 'cat %s' % deps_path
@@ -609,4 +616,3 @@
             'charts': charts,
             'format_version': 1.0
         }
-