Merge test results presentation of multiple shards.

build/android/pylib/results/presentation/standard_gtest_merge.py

Index: build/android/pylib/results/presentation/standard_gtest_merge.py
diff --git a/build/android/pylib/results/presentation/standard_gtest_merge.py b/build/android/pylib/results/presentation/standard_gtest_merge.py
new file mode 100755
index 0000000000000000000000000000000000000000..10754d995b2675fd18fdc4e0618d383b13c01e5e
--- /dev/null
+++ b/build/android/pylib/results/presentation/standard_gtest_merge.py
@@ -0,0 +1,164 @@
+#! /usr/bin/env python
+#
+# Copyright 2017 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.
+
+import argparse
+import json
+import os
+import sys
+
+
+def merge_shard_results(summary_json, jsons_to_merge):
+  """Reads JSON test output from all shards and combines them into one.
+
+  Returns dict with merged test output on success or None on failure. Emits
+  annotations.
+  """
+  try:
+    with open(summary_json) as f:
+      summary = json.load(f)
+  except (IOError, ValueError):
+    raise Exception('Summary json cannot be loaded.')
+
+  # Merge all JSON files together. Keep track of missing shards.
+  merged = {
+    'all_tests': set(),
+    'disabled_tests': set(),
+    'global_tags': set(),
+    'missing_shards': [],
+    'per_iteration_data': [],
+    'swarming_summary': summary,
+    'links': set()
+  }
+  for index, result in enumerate(summary['shards']):
+    if result is not None:
+      # Author note: this code path doesn't trigger convert_to_old_format() in
+      # client/swarming.py, which means the state enum is saved in its string
+      # name form, not in the number form.
+      state = result.get('state')
+      if state == u'BOT_DIED':
+        print >> sys.stderr, 'Shard #%d had a Swarming internal failure' % index
+      elif state == u'EXPIRED':
+        print >> sys.stderr, 'There wasn\'t enough capacity to run your test'
+      elif state == u'TIMED_OUT':
+        print >> sys.stderr, (
+            'Test runtime exceeded allocated time'
+            'Either it ran for too long (hard timeout) or it didn\'t produce '
+            'I/O for an extended period of time (I/O timeout)')
+      elif state == u'COMPLETED':
+        json_data, err_msg = load_shard_json(index, jsons_to_merge)
+        if json_data:
+          # Set-like fields.
+          for key in ('all_tests', 'disabled_tests', 'global_tags', 'links'):
+            merged[key].update(json_data.get(key), [])
+
+          # 'per_iteration_data' is a list of dicts. Dicts should be merged
+          # together, not the 'per_iteration_data' list itself.
+          merged['per_iteration_data'] = merge_list_of_dicts(
+              merged['per_iteration_data'],
+              json_data.get('per_iteration_data', []))
+          continue
+        else:
+          print >> sys.stderr, 'Task ran but no result was found: %s' % err_msg
+      else:
+        print >> sys.stderr, 'Invalid Swarming task state: %s' % state
+    merged['missing_shards'].append(index)
+
+  # If some shards are missing, make it known. Continue parsing anyway. Step
+  # should be red anyway, since swarming.py return non-zero exit code in that
+  # case.
+  if merged['missing_shards']:
+    as_str = ', '.join([str(shard) for shard in merged['missing_shards']])
+    print >> sys.stderr, ('some shards did not complete: %s' % as_str)
+    # Not all tests run, combined JSON summary can not be trusted.
+    merged['global_tags'].add('UNRELIABLE_RESULTS')
+
+  # Convert to jsonish dict.
+  for key in ('all_tests', 'disabled_tests', 'global_tags', 'links'):
+    merged[key] = sorted(merged[key])
+  return merged
+
+
+OUTPUT_JSON_SIZE_LIMIT = 100 * 1024 * 1024  # 100 MB
+
+
+def load_shard_json(index, jsons_to_merge):
+  """Reads JSON output of the specified shard.
+
+  Args:
+    jsons_to_merge: List of json files to be merge.
+    index: The index of the shard to load data for.
+
+  Returns: A tuple containing:
+    * The contents of path, deserialized into a python object.
+    * An error string.
+    (exactly one of the tuple elements will be non-None).
+  """
+  matching_json_files = [
+      j for j in jsons_to_merge
+      if (os.path.basename(j) == 'output.json'
+          and os.path.basename(os.path.dirname(j)) == str(index))]
+
+  if not matching_json_files:
+    print >> sys.stderr, 'shard %s test output missing' % index
+    return (None, 'shard %s test output was missing' % index)
+  elif len(matching_json_files) > 1:
+    print >> sys.stderr, 'duplicate test output for shard %s' % index
+    return (None, 'shard %s test output was duplicated' % index)
+
+  path = matching_json_files[0]
+
+  try:
+    filesize = os.stat(path).st_size
+    if filesize > OUTPUT_JSON_SIZE_LIMIT:
+      print >> sys.stderr, 'output.json is %d bytes. Max size is %d' % (
+           filesize, OUTPUT_JSON_SIZE_LIMIT)
+      return (None, 'shard %s test output exceeded the size limit' % index)
+
+    with open(path) as f:
+      return (json.load(f), None)
+  except (IOError, ValueError, OSError) as e:
+    print >> sys.stderr, 'Missing or invalid gtest JSON file: %s' % path
+    print >> sys.stderr, '%s: %s' % (type(e).__name__, e)
+
+    return (None, 'shard %s test output was missing or invalid' % index)
+
+
+def merge_list_of_dicts(left, right):
+  """Merges dicts left[0] with right[0], left[1] with right[1], etc."""
+  output = []
+  for i in xrange(max(len(left), len(right))):
+    left_dict = left[i] if i < len(left) else {}
+    right_dict = right[i] if i < len(right) else {}
+    merged_dict = left_dict.copy()
+    merged_dict.update(right_dict)
+    output.append(merged_dict)
+  return output
+
+
+def standard_gtest_merge(
+    output_json, summary_json, jsons_to_merge):
+
+  output = merge_shard_results(summary_json, jsons_to_merge)
+  with open(output_json, 'wb') as f:
+    json.dump(output, f)
+
+  return 0
+
+
+def main(raw_args):
+  parser = argparse.ArgumentParser()
+  parser.add_argument('--summary-json')
+  parser.add_argument('-o', '--output-json', required=True)
+  parser.add_argument('jsons_to_merge', nargs='*')
+
+  args = parser.parse_args(raw_args)
+
+  return standard_gtest_merge(
+      args.output_json, args.summary_json, args.jsons_to_merge)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))