Openstack Gerrit code review process details

Are you looking to contribute code to one of the Openstack projects (example include Nova, Quantum or Glance and many more). If the answer is yes, you definitely need to get familiar with the code review that Openstack enforces. A good overview of what this is can be found here Code review process in Openstack uses Zuul.

On a technical site the process has been implemented with a help of Gerrit system. From end user perspective you get access to a nice and good looking page in a browser that helps you to review, comment and approve code changes that should be committed to master repository. A quick and good introduction of what Gerrit do this and how it helps can be found here: Gerrit Code Review - A Quick Introduction.

Example how this interface looks like:

Code Review: https://review.openstack.org

When you select a link you dig into more details: (example) https://review.openstack.org/#/c/23878/

In this screen we can find:

• linked Bug id if exists (https://code.launchpad.net/bugs/1131759) 
• linked Blueprints if exists
• reviewer list
• one or more patches with proposed code changes
• comments and suggestions before the code can be accepted in the mainstream repository

But the best part of Gerrit is its capability to pull the original file and create a diff to visual the changes. An example from the review #23878 is seen below.

https://review.openstack.org/#/c/23878/4/heat/tests/test_api_openstack_v1.py

Code review process in Openstack uses Zuul

For a modern software development process to be effective as well as developer friendly it requires a usage of automation systems like:

• Continuous integration
• Build automation
• Automated unit and integration testing
• Rreview process
• (distributed) Version control system

In Openstack the process has been implemented in the following way.

Further info about the components and how this works together you can watch this video as well[1].

References

1. http://www.youtube.com/watch?v=e2H4dfJTx68&feature=em-subs_digest-newavtr
2. https://github.com/openstack-ci/zuul/
3. http://www.slideshare.net/lzyeval/assign-commit-and-review