From c41de8ded6e866166640a09ac31a27ff6fed0fb8 Mon Sep 17 00:00:00 2001
From: Jimmy Zelinskie <jimmy.zelinskie+git@gmail.com>
Date: Tue, 6 Dec 2016 20:40:54 -0500
Subject: [PATCH] build queue rate limiting: address PR comments

---
 data/queue.py          |  2 +-
 endpoints/api/build.py |  1 +
 endpoints/building.py  | 14 +++++++++-----
 endpoints/webhooks.py  |  2 +-
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/data/queue.py b/data/queue.py
index 659a485b0..07135b746 100644
--- a/data/queue.py
+++ b/data/queue.py
@@ -79,7 +79,7 @@ class WorkQueue(object):
 
   def num_available_jobs_between(self, available_min_time, available_max_time, prefix):
     """
-    Returns the number of available queue items with a given prefix between the two provided times.
+    Returns the number of available queue items with a given prefix, between the two provided times.
     """
     prefix = prefix.lstrip('/')
     available = self._available_jobs(available_max_time,
diff --git a/endpoints/api/build.py b/endpoints/api/build.py
index 36daf2bde..0b2ef5464 100644
--- a/endpoints/api/build.py
+++ b/endpoints/api/build.py
@@ -291,6 +291,7 @@ class RepositoryBuildList(RepositoryParamResource):
       build_request = start_build(repo, prepared, pull_robot_name=pull_robot_name)
     except MaximumBuildsQueuedException:
       abort(429, message='Maximum queued build rate exceeded.')
+
     resp = build_status_view(build_request)
     repo_string = '%s/%s' % (namespace, repository)
     headers = {
diff --git a/endpoints/building.py b/endpoints/building.py
index d2684c8b8..83fd9e028 100644
--- a/endpoints/building.py
+++ b/endpoints/building.py
@@ -16,23 +16,27 @@ from util.morecollections import AttrDict
 
 logger = logging.getLogger(__name__)
 
-MAX_BUILD_QUEUE_ITEMS = app.config.get('MAX_BUILD_QUEUE_ITEMS', -1)
-MAX_BUILD_QUEUE_SECS = app.config.get('MAX_BUILD_QUEUE_SECS', -1)
+MAX_BUILD_QUEUE_RATE_ITEMS = app.config.get('MAX_BUILD_QUEUE_RATE_ITEMS', -1)
+MAX_BUILD_QUEUE_RATE_SECS = app.config.get('MAX_BUILD_QUEUE_RATE_SECS', -1)
 
 
 class MaximumBuildsQueuedException(Exception):
+  """
+  This exception is raised when a build is requested, but the incoming build
+  would exceed the configured maximum build rate.
+  """
   pass
 
 
 def start_build(repository, prepared_build, pull_robot_name=None):
   queue_item_prefix = '%s/%s' % (repository.namespace_user.username, repository.name)
-  if MAX_BUILD_QUEUE_ITEMS > 0 and MAX_BUILD_QUEUE_SECS > 0:
+  if MAX_BUILD_QUEUE_RATE_ITEMS > 0 and MAX_BUILD_QUEUE_RATE_SECS > 0:
     now = datetime.utcnow()
-    available_min = now - timedelta(seconds=MAX_BUILD_QUEUE_SECS)
+    available_min = now - timedelta(seconds=MAX_BUILD_QUEUE_RATE_SECS)
     available_builds = dockerfile_build_queue.num_available_jobs_between(available_min,
                                                                          now,
                                                                          queue_item_prefix)
-    if available_builds > MAX_BUILD_QUEUE_ITEMS:
+    if available_builds >= MAX_BUILD_QUEUE_RATE_ITEMS:
       raise MaximumBuildsQueuedException()
 
   host = app.config['SERVER_HOSTNAME']
diff --git a/endpoints/webhooks.py b/endpoints/webhooks.py
index c89d9b26e..79a3e58d1 100644
--- a/endpoints/webhooks.py
+++ b/endpoints/webhooks.py
@@ -107,7 +107,7 @@ def build_trigger_webhook(trigger_uuid, **kwargs):
     try:
       start_build(repo, prepared, pull_robot_name=pull_robot_name)
     except MaximumBuildsQueuedException:
-      abort(429)
+      abort(429, message='Maximum queued build rate exceeded.')
 
     return make_response('Okay')