Third Party Testing

Overview

Gerrit has an event stream which can be subscribed to, using this it is possible to test commits against testing systems beyond those supplied by OpenStack’s Jenkins setup. It is also possible for these systems to feed information back into Gerrit and they can also leave non-gating votes on Gerrit review requests.

An example of one such system is Smokestack. Smokestack reads the Gerrit event stream and runs it’s own tests on the commits. If one of the tests fails it will publish information and links to the failure on the review in Gerrit.

Reading the Event Stream

It is possible to use ssh to connect to review.openstack.org on port 29418 with your ssh key if you have a normal reviewer account in Gerrit.

This will give you a real-time JSON stream of events happening inside Gerrit. For example:

$ ssh -p 29418 review.example.com gerrit stream-events

Will give a stream with an output like this (line breaks and indentation added in this document for readability, the read JSON will be all one line per event):

{"type":"comment-added","change":
  {"project":"openstack/keystone","branch":"stable/essex","topic":"bug/969088","id":"I18ae38af62b4c2b2423e20e436611fc30f844ae1","number":"7385","subject":"Make import_nova_auth only create roles which don\u0027t already exist","owner":
    {"name":"Chuck Short","email":"[email protected]","username":"zulcss"},"url":"https://review.openstack.org/7385"},
  "patchSet":
    {"number":"1","revision":"aff45d69a73033241531f5e3542a8d1782ddd859","ref":"refs/changes/85/7385/1","uploader":
      {"name":"Chuck Short","email":"[email protected]","username":"zulcss"},
    "createdOn":1337002189},
  "author":
    {"name":"Mark McLoughlin","email":"[email protected]","username":"markmc"},
  "approvals":
    [{"type":"CRVW","description":"Code Review","value":"2"},{"type":"APRV","description":"Approved","value":"0"}],
"comment":"Hmm, I actually thought this was in Essex already.\n\nIt\u0027s a pretty annoying little issue for folks migrating for nova auth. Fix is small and pretty safe. Good choice for backporting"}

For most purposes you will want to trigger on patchset-created for when a new patchset has been uploaded.

Further documentation on how to use the events stream can be found in Gerrit’s stream event documentation page.

Posting Result To Gerrit

External testing systems can give non-gating votes to Gerrit by means of a -1/+1 verify vote. OpenStack Jenkins has extra permissions to give a +2/-2 verify vote which is gating. Comments should also be provided to explain what kind of test failed.. We do also ask that the comments contain public links to the failure so that the developer can see what caused the failure.

An example of how to post this is as follows:

$ ssh -p 29418 review.example.com gerrit review -m '"Test failed on MegaTestSystem <http://megatestsystem.org/tests/1234>"' --verified=-1 c0ff33

In this example c0ff33 is the commit ID for the review. You can set the verified to either -1 or +1 depending on whether or not it passed the tests.

Further documentation on the review command in Gerrit can be found in the Gerrit review documentation page.

We do suggest cautious testing of these systems and have a development Gerrit setup to test on if required. In SmokeStack’s case all failures are manually reviewed before getting pushed to OpenStack, whilst this may no scale it is advisable during initial testing of the setup.

Requesting a Service Account

Feel free to contact the OpenStack Infrastructure Team via email, bug report or in the #openstack-infra IRC channel to arrange setting up a dedicated user (so your system can post reviews and vote using a system name rather than your user name). You should provide a preferred account name, SSH public key and if possible a unique contact email address for that system, though it should not be an address used by any existing Gerrit account.

The Jenkins Gerrit Trigger Plugin Way

There is a Gerrit Trigger plugin for Jenkins which automates all of the processes described in this document. So if your testing system is Jenkins based you can use it to simplify things. You will still need an account to do this as described in the Requesting a Service Account section above.

The OpenStack version of the Gerrit Trigger plugin for Jenkins can be found on the Jenkins packaging job for it. You can install it using the Advanced tab in the Jenkins Plugin Manager.

Once installed Jenkins will have a new Gerrit Trigger option in the Manage Jenkins menu. This should be given the following options:

Hostname: review.openstack.org
Frontend URL: https://review.openstack.org/
SSH Port: 29418
Username: (the Gerrit user)
SSH Key File: (path to the user SSH key)

Verify
------
Started: 0
Successful: 1
Failed: -1
Unstable: 0

Code Review
-----------
Started: 0
Successful: 0
Failed: 0
Unstable: 0

(under Advanced Button):

Stated: (blank)
Successful: gerrit approve <CHANGE>,<PATCHSET> --message 'Build Successful <BUILDS_STATS>' --verified <VERIFIED> --code-review <CODE_REVIEW> --submit
Failed: gerrit approve <CHANGE>,<PATCHSET> --message 'Build Failed <BUILDS_STATS>' --verified <VERIFIED> --code-review <CODE_REVIEW>
Unstable: gerrit approve <CHANGE>,<PATCHSET> --message 'Build Unstable <BUILDS_STATS>' --verified <VERIFIED> --code-review <CODE_REVIEW>

Note that it is useful to include something in the messages about what testing system is supplying these messages.

When creating jobs in Jenkins you will have the option to add triggers. You should configure as follows:

Trigger on Patchset Uploaded: ticked
(the rest unticked)

Type: Plain
Pattern: openstack/project-name (where project-name is the name of the project)
Branches:
  Type: Path
  Pattern: **

This job will now automatically trigger when a new patchset is uploaded and will report the results to Gerrit automatically.