Add analytics_notifier to post build results.

Summary:
This adds an optional mechanism to post build results as a JSON
dictionary to an HTTP address to allow builds to be sent in realtime
to external analytics services.

Test Plan: Light unit.

Reviewers: jukka

Reviewed By: jukka

Subscribers: changesbot, wwu, jukka

Differential Revision: https://tails.corp.dropbox.com/D90885

changes/config.py

@@ -157,6 +157,7 @@ def create_app(_read_config=True, **config):
         ('changes.listeners.hipchat.build_finished_handler', 'build.finished'),
         ('changes.listeners.build_revision.revision_created_handler', 'revision.created'),
         ('changes.listeners.phabricator_listener.build_finished_handler', 'build.finished'),
+        ('changes.listeners.analytics_notifier.build_finished_handler', 'build.finished'),
     )
 
     # restrict outbound notifications to the given domains

changes/listeners/analytics_notifier.py

@@ -0,0 +1,67 @@
+"""Posts JSON with basic information for each completed build to the URL specified
+in the config variable ANALYTICS_POST_URL, if that value is set.
+
+The data posted to ANALYTICS_POST_URL will be a JSON array of objects, with each
+object representing a completed build.
+"""
+
+import logging
+import json
+import requests
+from datetime import datetime
+
+from flask import current_app
+
+from changes.models import Build
+
+logger = logging.getLogger('analytics_notifier')
+
+
+def _datetime_to_timestamp(dt):
+    """Convert a datetime to unix epoch time in seconds."""
+    return int((dt - datetime.utcfromtimestamp(0)).total_seconds())
+
+
+def build_finished_handler(build_id, **kwargs):
+    url = current_app.config.get('ANALYTICS_POST_URL')
+    if not url:
+        return
+    build = Build.query.get(build_id)
+    if build is None:
+        return
+
+    def maybe_ts(dt):
+        if dt:
+            return _datetime_to_timestamp(dt)
+        return None
+
+    data = {
+        'build_id': build.id.hex,
+        'result': unicode(build.result),
+        'project_slug': build.project.slug,
+        'is_commit': bool(build.source.is_commit()),
+        'label': build.label,
+        'number': build.number,
+        'duration': build.duration,
+        'target': build.target,
+        'date_created': maybe_ts(build.date_created),
+        'date_started': maybe_ts(build.date_started),
+        'date_finished': maybe_ts(build.date_finished),
+    }
+    if build.author:
+        data['author'] = build.author.email
+
+    post_build_data(url, data)
+
+
+def post_build_data(url, data):
+    try:
+        # NB: We send an array of JSON objects rather than a single object
+        # so the interface doesn't need to change if we later want to do batch
+        # posting.
+        resp = requests.post(url, data=json.dumps([data]))
+        resp.raise_for_status()
+        # Should probably retry here so that transient failures don't result in
+        # missing data.
+    except Exception:
+        logger.exception("Failed to post to Analytics")

changes/models/build.py

@@ -46,7 +46,9 @@ class Build(db.Model):
     source_id = Column(GUID, ForeignKey('source.id', ondelete="CASCADE"))
     author_id = Column(GUID, ForeignKey('author.id', ondelete="CASCADE"))
     cause = Column(EnumType(Cause), nullable=False, default=Cause.unknown)
+    # label is a short description, typically from the title of the change that triggered the build.
     label = Column(String(128), nullable=False)
+    # short indicator of what is being built, typically the sha or the Phabricator revision ID like 'D90885'.
     target = Column(String(128))
     tags = Column(ARRAY(String(16)), nullable=True)
     status = Column(EnumType(Status), nullable=False, default=Status.unknown)

tests/changes/listeners/test_analytics_notifier.py

@@ -0,0 +1,62 @@
+from __future__ import absolute_import
+
+from datetime import datetime
+
+from flask import current_app
+import mock
+
+from changes.constants import Result
+from changes.testutils import TestCase
+from changes.listeners.analytics_notifier import build_finished_handler
+
+
+class AnalyticsNotifierTest(TestCase):
+
+    def setUp(self):
+        super(AnalyticsNotifierTest, self).setUp()
+
+    def _set_config_url(self, url):
+        current_app.config['ANALYTICS_POST_URL'] = url
+
+    @mock.patch('changes.listeners.analytics_notifier.post_build_data')
+    def test_no_url(self, post_fn):
+        self._set_config_url(None)
+        project = self.create_project(name='test', slug='test')
+        build = self.create_build(project, result=Result.failed)
+        build_finished_handler(build_id=build.id.hex)
+        self.assertEquals(post_fn.call_count, 0)
+
+    @mock.patch('changes.listeners.analytics_notifier.post_build_data')
+    def test_failed_build(self, post_fn):
+        URL = "https://analytics.example.com/report?source=changes"
+        self._set_config_url(URL)
+        project = self.create_project(name='test', slug='project-slug')
+        self.assertEquals(post_fn.call_count, 0)
+        duration = 1234
+        created = 1424998888
+        started = created + 10
+        finished = started + duration
+
+        def ts_to_datetime(ts):
+            return datetime.utcfromtimestamp(ts)
+
+        build = self.create_build(project, result=Result.failed, target='D1',
+                                  label='Some sweet diff', duration=duration,
+                                  date_created=ts_to_datetime(created), date_started=ts_to_datetime(started),
+                                  date_finished=ts_to_datetime(finished))
+        build_finished_handler(build_id=build.id.hex)
+
+        expected_data = {
+            'build_id': build.id.hex,
+            'number': 1,
+            'target': 'D1',
+            'project_slug': 'project-slug',
+            'result': 'Failed',
+            'label': 'Some sweet diff',
+            'is_commit': True,
+            'duration': 1234,
+            'date_created': created,
+            'date_started': started,
+            'date_finished': finished,
+        }
+        post_fn.assert_called_once_with(URL, expected_data)