version: master
page: jenkins-sandbox

The recipe in [0] is missing some essential steps.  Please revise the steps as follows:

1. Login into the Jenkins Sandbox WebUI

1. Click on the job which you want to trigger

1. The first time you execute a job, add a gerrit refspec to the configuration:
   1. Click 'Configure'
   2. Click 'Source Code Management'
   3. Click 'Advanced'
   4. Change the value of 'Refspec' from "$GERRIT_REFSPEC" to the refspec of the gerrit change version to run the job against.  (eg. refs/changes/04/27204/1, see [1] for how to determine the latest refspec of a gerrit change)
   5. 'Click Apply'
2. Click "Build with parameters"

1. Click Build

1. Verify the Build Executor Status bar to check on progress.

[0] https://docs.releng.linuxfoundation.org/en/latest/jenkins-sandbox.html#execute-jobs-in-the-sandbox

[1] https://stackoverflow.com/questions/22264533/obtain-the-latest-refspec-on-a-gerrit-change

For example:

$ ssh -p 29418 gerrit.fd.io gerrit query --current-patch-set --format=JSON change:26767 | tr ',' '\n' | grep refs
"ref":"refs/changes/67/26767/5"

(Note: the last number in the refspec is the gerrit patch version)