Relanding updates to swarming api to add chartjson output.

scripts/slave/recipe_modules/swarming/api.py

Index: scripts/slave/recipe_modules/swarming/api.py
diff --git a/scripts/slave/recipe_modules/swarming/api.py b/scripts/slave/recipe_modules/swarming/api.py
index de26cf14f11a01db085f0a8f4b7654c3a986b60e..8bc0bb3a696c2e0ac960e197f8dc0b9cd2cd2b7d 100644
--- a/scripts/slave/recipe_modules/swarming/api.py
+++ b/scripts/slave/recipe_modules/swarming/api.py
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import logging
 import datetime
 import functools
 
@@ -407,6 +408,19 @@ class SwarmingApi(recipe_api.RecipeApi):
         self._gtest_collect_step(test_launcher_summary_output, *args, **kw))
     return task
 
+  def _check_and_set_output_flag(self, extra_args, flag, output_file_name):
+    extra_args = list(extra_args or [])
+    # Ensure flag is not already passed. We are going to overwrite it.
+    flag_value = '--%s=' % flag
+    bad_args = any(x.startswith(flag_value) for x in extra_args)
+    if bad_args: # pragma: no cover
+      raise ValueError('--%s should not be used' % flag)
+
+    # Append it.
+    output_arg = '--%s=${ISOLATED_OUTDIR}/%s' % (flag, output_file_name)
+    extra_args.append(output_arg)
+    return extra_args
+
   def isolated_script_task(self, title, isolated_hash, extra_args=None,
                            idempotent=False, **kwargs):
     """Returns a new SwarmingTask to run an isolated script test on Swarming.
@@ -418,18 +432,18 @@ class SwarmingApi(recipe_api.RecipeApi):
 
     For meaning of the rest of the arguments see 'task' method.
     """
-    extra_args = list(extra_args or [])
-
-    # Ensure --isolated-script-test-output is not already passed. We are going
-    # to overwrite it.
-    bad_args = any(
-        x.startswith('--isolated-script-test-output=') for x in extra_args)
-    if bad_args:  # pragma: no cover
-      raise ValueError('--isolated-script-test-output should not be used.')
 
-    # Append it. output.json name is expected by collect_gtest_task.py.
-    extra_args.append(
-        '--isolated-script-test-output=${ISOLATED_OUTDIR}/output.json')
+    # Ensure output flags are not already passed. We are going
+    # to overwrite them.
+    # output.json name is expected by collect_gtest_task.py.
+    extra_args = self._check_and_set_output_flag(
+      extra_args, 'isolated-script-test-output', 'output.json')
+    # chartjson-output.json name is expected by benchmarks generating chartjson
+    # output
+    extra_args = self._check_and_set_output_flag(
+      extra_args,
+      'isolated-script-test-chartjson-output',
+      'chartjson-output.json')
 
     task = self.task(title, isolated_hash, extra_args=extra_args,
                      idempotent=idempotent, **kwargs)
@@ -717,6 +731,46 @@ class SwarmingApi(recipe_api.RecipeApi):
             p.links[link_name] = outputs_ref['view_url']
 
 
+  def _merge_isolated_script_chartjson_ouput_shards(self, task, step_result):
+    # Taken from third_party/catapult/telemetry/telemetry/internal/results/
+    # chart_json_output_formatter.py, the json entries are as follows:
+    # result_dict = {
+    #   'format_version': '0.1',
+    #   'next_version': '0.2',
+    #   'benchmark_name': benchmark_metadata.name,
+    #   'benchmark_description': benchmark_metadata.description,
+    #   'trace_rerun_options': benchmark_metadata.rerun_options,
+    #   'benchmark_metadata': benchmark_metadata.AsDict(),
+    #   'charts': charts,
+    # }
+    #
+    # Therefore, all entries should be the same and we should only need to merge
+    # the chart from each shard.
+    merged_results = {}
+    seen_first_shard = False
+    for i in xrange(task.shards):
+      path = self.m.path.join(str(i), 'chartjson-output.json')
+      if path not in step_result.raw_io.output_dir:
+        # chartjson results were not written for this shard, not an error,
+        # just continue to the next shard
+        continue
+      results_raw = step_result.raw_io.output_dir[path]
+      try:
+        chartjson_results_json = self.m.json.loads(results_raw)
+      except Exception as e:
+        raise Exception('error decoding chart JSON results from shard #%d' % i)
+      if not seen_first_shard:
+        merged_results = chartjson_results_json
+        seen_first_shard = True
+        continue
+      for key in chartjson_results_json:
+        if key == 'charts':
+          # Append each additional chart to our merged results
+          for add_key in chartjson_results_json[key]:
+            merged_results[key][add_key] = chartjson_results_json[key][add_key]
+    return merged_results
+
+
   def _merge_isolated_script_shards(self, task, step_result):
     # This code is unfortunately specialized to the "simplified"
     # JSON format that used to be the standard for recipes. The
@@ -799,6 +853,10 @@ class SwarmingApi(recipe_api.RecipeApi):
         step_result.isolated_script_results = \
           self._merge_isolated_script_shards(task, step_result)
 
+        # Obtain chartjson results if present
+        step_result.isolated_script_chartjson_results = \
+          self._merge_isolated_script_chartjson_ouput_shards(task, step_result)
+
         self._display_pending(summary, step_result.presentation)
       except Exception as e:
         self.m.step.active_result.presentation.logs['no_results_exc'] = [str(e)]