[Findit] Add a sub-pipeline to detect first-known failure.

appengine/findit/waterfall/detect_first_failure_pipeline.py

Index: appengine/findit/waterfall/detect_first_failure_pipeline.py
diff --git a/appengine/findit/waterfall/detect_first_failure_pipeline.py b/appengine/findit/waterfall/detect_first_failure_pipeline.py
new file mode 100644
index 0000000000000000000000000000000000000000..fa62e606811981ae02989ac620ac26d9d0b56d92
--- /dev/null
+++ b/appengine/findit/waterfall/detect_first_failure_pipeline.py
@@ -0,0 +1,244 @@
+# Copyright 2014 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 collections
+from datetime import datetime
+import logging
+import random
+import time
+
+from google.appengine.api import memcache
+
+from pipeline_utils.appengine_third_party_pipeline_src_pipeline import pipeline
+
+from common.http_client_appengine import HttpClientAppengine as HttpClient
+from model.build import Build
+from model.build_analysis import BuildAnalysis
+from waterfall import buildbot
+from waterfall.base_pipeline import BasePipeline
+from waterfall import lock_util
+
+
+_MAX_BUILDS_TO_CHECK = 20
+
+
+class DetectFirstFailurePipeline(BasePipeline):
+  """ A pipeline to detect first failure of each step.
+
+  TODO(stgao): do test-level detection for gtest.
+
+  Input:
+    master_name
+    builder_name
+    build_number
+
+  Output:
+    A json like below:
+    {
+      "master_name": "chromium.gpu",
+      "builder_name": "GPU Linux Builder"
+      "build_number": 25410,
+      "failed": true,
+      "failed_steps": {
+        "compile": {
+          "last_pass": 25408,
+          "current_failure": 25410,
+          "first_failure": 25409
+        }
+      },
+      "builds": {
+        "25408": {
+          "chromium_revision": "474ab324d17d2cd198d3fb067cabc10a775a8df7"
+          "blame_list": [
+            "474ab324d17d2cd198d3fb067cabc10a775a8df7"
+          ],
+        },
+        "25409": {
+          "chromium_revision": "33c6f11de20c5b229e102c51237d96b2d2f1be04"
+          "blame_list": [
+            "9d5ebc5eb14fc4b3823f6cfd341da023f71f49dd",
+            ...
+          ],
+        },
+        "25410": {
+          "chromium_revision": "4bffcd598dd89e0016208ce9312a1f477ff105d1"
+          "blame_list": [
+            "b98e0b320d39a323c81cc0542e6250349183a4df",
+            ...
+          ],
+        }
+      }
+    }
+  """
+
+  HTTP_CLIENT = HttpClient()
+
+  def _BuildDataNeedUpdating(self, build):
+    return (not build.data or (not build.completed and
+        (datetime.utcnow() - build.last_crawled_time).total_seconds() >= 300))
+
+  def _DownloadBuildData(self, master_name, builder_name, build_number):
+    """Downloads build data and returns a Build instance."""
+    build = Build.GetBuild(master_name, builder_name, build_number)
+    if not build:
+      build = Build.CreateBuild(master_name, builder_name, build_number)
+
+    # Cache the data to avoid pulling from master again.
+    if self._BuildDataNeedUpdating(build):
+      if not lock_util.WaitUntilDownloadAllowed(
+          master_name):  # pragma: no cover
+        raise pipeline.Retry('Too many download from %s' % master_name)
+
+      build.data = buildbot.GetBuildData(
+          build.master_name, build.builder_name, build.build_number,
+          self.HTTP_CLIENT)
+      build.last_crawled_time = datetime.utcnow()
+      build.put()
+
+    return build
+
+  def _ExtractBuildInfo(self, master_name, builder_name, build_number):
+    """Returns a BuildInfo instance for the specified build."""
+    build = self._DownloadBuildData(master_name, builder_name, build_number)
+    if not build.data:  # pragma: no cover
+      return None
+
+    build_info = buildbot.ExtractBuildInfo(
+        master_name, builder_name, build_number, build.data)
+
+    if not build.completed:
+      build.start_time = build_info.build_start_time
+      build.completed = build_info.completed
+      build.result = build_info.result
+      build.put()
+
+    analysis = BuildAnalysis.GetBuildAnalysis(
+        master_name, builder_name, build_number)
+    if analysis and not analysis.build_start_time:
+      analysis.build_start_time = build_info.build_start_time
+      analysis.put()
+
+    return build_info
+
+  def _SaveBlamelistAndChromiumRevisionIntoDict(self, build_info, builds):
+    """
+    Args:
+      build_info (BuildInfo): a BuildInfo instance which contains blame list and
+          chromium revision.
+      builds (dict): to which the blame list and chromium revision is saved. It
+          will be updated and looks like:
+          {
+            555 : {
+              'chromium_revision': 'a_git_hash',
+              'blame_list': ['git_hash1', 'git_hash2'],
+            },
+          }
+    """
+    builds[build_info.build_number] = {
+        'chromium_revision': build_info.chromium_revision,
+        'blame_list': build_info.blame_list
+    }
+
+  def _CreateADictOfFailedSteps(self, build_info):
+    """ Returns a dict with build number for failed steps.
+
+    Args:
+      failed_steps (list): a list of failed steps.
+
+    Returns:
+      A dict like this:
+      {
+        'step_name': {
+          'current_failure': 555,
+          'first_failure': 553,
+        },
+      }
+    """
+    failed_steps = dict()
+    for step_name in build_info.failed_steps:
+      failed_steps[step_name] = {
+          'current_failure': build_info.build_number,
+          'first_failure': build_info.build_number,
+      }
+
+    return failed_steps
+
+  def _CheckForFirstKnownFailure(self, master_name, builder_name, build_number,
+                                 failed_steps, builds):
+    """Checks for first known failures of the given failed steps.
+
+    Args:
+      master_name (str): master of the failed build.
+      builder_name (str): builder of the failed build.
+      build_number (int): builder number of the current failed build.
+      failed_steps (dict): the failed steps of the current failed build. It will
+          be updated with build numbers for 'first_failure' and 'last_pass' of
+          each failed step.
+      builds (dict): a dict to save blame list and chromium revision.
+    """
+    # Look back for first known failures.
+    for i in range(_MAX_BUILDS_TO_CHECK):  # limit not hit - pragma: no cover
+      build_info = self._ExtractBuildInfo(
+          master_name, builder_name, build_number - i - 1)
+
+      if not build_info:  # pragma: no cover
+        # Failed to extract the build information, bail out.
+        return
+
+      self._SaveBlamelistAndChromiumRevisionIntoDict(build_info, builds)
+
+      if build_info.result == buildbot.SUCCESS:
+        for step_name in failed_steps:
+          if 'last_pass' not in failed_steps[step_name]:
+            failed_steps[step_name]['last_pass'] = build_info.build_number
+
+        # All steps passed, so stop looking back.
+        return
+      else:
+        # If a step is not run due to some bot exception, we are not sure
+        # whether the step could pass or not. So we only check failed/passed
+        # steps here.
+
+        for step_name in build_info.failed_steps:
+          if step_name in failed_steps:
+            failed_steps[step_name]['first_failure'] = build_info.build_number
+
+        for step_name in failed_steps:
+          if step_name in build_info.passed_steps:
+            failed_steps[step_name]['last_pass'] = build_info.build_number
+
+        if all('last_pass' in step_info for step_info in failed_steps.values()):
+          # All failed steps passed in this build cycle.
+          return
+
+  # Arguments number differs from overridden method - pylint: disable=W0221
+  def run(self, master_name, builder_name, build_number):
+    build_info = self._ExtractBuildInfo(master_name, builder_name, build_number)
+
+    if not build_info:  # pragma: no cover
+      raise pipeline.Retry('Failed to extract build info.')
+
+    failure_info = {
+        'failed': True,
+        'master_name': master_name,
+        'builder_name': builder_name,
+        'build_number': build_number
+    }
+
+    if (build_info.result == buildbot.SUCCESS or
+        not build_info.failed_steps):
+      failure_info['failed'] = False
+      return failure_info
+
+    builds = dict()
+    self._SaveBlamelistAndChromiumRevisionIntoDict(build_info, builds)
+
+    failed_steps = self._CreateADictOfFailedSteps(build_info)
+
+    self._CheckForFirstKnownFailure(
+        master_name, builder_name, build_number, failed_steps, builds)
+
+    failure_info['builds'] = builds
+    failure_info['failed_steps'] = failed_steps
+    return failure_info