The Gatekeeper, or a project gating system
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Tobias Henkel 4c972f00bd
Optimize canMerge using graphql
The canMerge check is executed whenever zuul tests if a change can
enter a gate pipeline. This is part of the critical path in the event
handling of the scheduler and therefore must be as fast as
possible. Currently this takes five requests for doing its work and
also transfers large amounts of data that is unneeded:

* get pull request
* get branch protection settings
* get commits
* get status of latest commit
* get check runs of latest commit

Especially when Github is busy this can slow down zuul's event
processing considerably. This can be optimized using graphql to only
query the data we need with a single request. This reduces requests
and load on Github and speeds up event processing in the scheduler.

Since this is the first usage of graphql this also sets up needed
testing infrastructure using graphene to mock the github api with real
test data.

Change-Id: I77be4f16cf7eb5c8035ce0312f792f4e8d4c3e10
2020-02-28 09:43:56 +01:00
doc Merge "Add foreground option" 2020-02-23 15:53:45 +00:00
etc authentication config: add optional max_validity_time, skew 2019-12-10 16:39:29 +01:00
playbooks cleanup: install docker-compose via role 2020-02-14 21:34:36 +01:00
releasenotes/notes Implement basic github checks API workflow 2020-02-19 13:31:49 +01:00
tests Optimize canMerge using graphql 2020-02-28 09:43:56 +01:00
tools Make most test cases work on MacOS 2020-02-20 12:59:38 +01:00
web ui: convert all spaces to commas for filter 2020-02-21 15:11:53 +01:00
zuul Optimize canMerge using graphql 2020-02-28 09:43:56 +01:00
.coveragerc Revert "Revert "Switch to stestr"" 2018-05-17 08:33:40 -07:00
.dockerignore Add web/node_modules to dockerignore 2019-01-27 11:23:45 +01:00
.gitignore Fix ignored but tracked .keep file 2018-12-02 09:12:25 +01:00
.gitreview OpenDev Migration Patch 2019-04-19 19:25:28 +00:00
.mailmap Fix pep8 E127 violations 2012-09-26 14:23:10 +00:00
.stestr.conf Revert "Revert "Switch to stestr"" 2018-05-17 08:33:40 -07:00
.zuul.yaml Increase timeout of zuul-build-image 2020-02-04 15:16:47 +01:00
COPYING Update README and add GPL license 2018-03-19 09:25:52 -07:00
Dockerfile Add foreground option 2020-02-22 17:59:24 +01:00
LICENSE Initial commit. 2012-05-29 14:49:32 -07:00 Optimize canMerge using graphql 2020-02-28 09:43:56 +01:00
README.rst Support nodes setting 'auto' python-path 2019-09-19 10:28:53 +10:00
TESTING.rst Docs: fix stestr run example 2020-01-21 10:36:07 +01:00
bindep.txt bindep: fixed wrong dep names on rpm platform 2020-01-20 14:30:10 +00:00
requirements.txt Optimize canMerge using graphql 2020-02-28 09:43:56 +01:00
setup.cfg Cleanup executor specific requirements 2019-04-04 08:58:04 +02:00 Partial sync with OpenStack requirements. 2013-09-25 15:30:37 -07:00
test-requirements.txt Optimize canMerge using graphql 2020-02-28 09:43:56 +01:00
tox.ini Don't set OS_LOG_DEFAULTS if unset 2020-02-17 21:41:00 +00:00



Zuul is a project gating system.

The latest documentation for Zuul v3 is published at:

If you are looking for the Edge routing service named Zuul that is related to Netflix, it can be found here:

If you are looking for the Javascript testing tool named Zuul, it can be found here:

Getting Help

There are two Zuul-related mailing lists:


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General discussion about Zuul, including questions about how to use it, and future development.

You will also find Zuul developers in the #zuul channel on Freenode IRC.


To browse the latest code, see: To clone the latest code, use git clone

Bugs are handled at:!/project/zuul/zuul

Suspected security vulnerabilities are most appreciated if first reported privately following any of the supported mechanisms described at

Code reviews are handled by gerrit at

After creating a Gerrit account, use git review to submit patches. Example:

# Do your commits
$ git review
# Enter your username if prompted

Join #zuul on Freenode to discuss development or usage.


Zuul is free software. Most of Zuul is licensed under the Apache License, version 2.0. Some parts of Zuul are licensed under the General Public License, version 3.0. Please see the license headers at the tops of individual source files.

Python Version Support

Zuul requires Python 3. It does not support Python 2.

Since Zuul uses Ansible to drive CI jobs, Zuul can run tests anywhere Ansible can, including Python 2 environments.