How to pass pipeline variables to post build gerrit message? - jenkins

Question

I have a Pylint running in a Jenkins pipeline. To implement it, I used Gerrit trigger plugin and Next Generation Warnings plugin. Everything is working as expected - Jenkins is joining the review, checks change with pylint and generates report.
Now, I'd like to post pylint score in a custom "Build successful" message. I wanted to pass the pylint score to a environment variable and use it in dedicated window for Gerrit plugin message.
Unfortunately no matter what I try, I cannot pass any "new" variable to the message. Passing parameters embedded in pipeline works (e.g. patchset number).
I created new environment variable in Configure Jenkins menu, tried exporting to shell, writing to it (via $VAR and env. syntax) but nothing works - that is, build message displays raw string like $VAR instead of what variable contains.
What should I do to pass local pylint score (distinct for every pipeline occurence) to the custom build message for Gerrit?

Answer 1

I don't think the custom message can be used for this. This is just supposed to be a static message.
They way I do this is to use the SSH command to perform the review. You can also achieve the same using the REST API.
First I run my linting and white space checking script that will generate a json file with the information I would like to pass to Gerrit. Next I send it to Gerrit using SSH. See below my pipeline script and an example json file.
As a bonus I have added the robot comments. This will now show up in your review as a remark from Jenkins that line 8 of my Jenkins file has a trailing white space. You can easily replace this with your lint result of you like or just ignore it and only put the message. It is easier to use a json file as it will make it easier to create multi line messages
node('master') {
sh """
cat lint_change.json | ssh -p ${env.GERRIT_PORT} ${env.GERRIT_HOST} gerrit review ${env.GERRIT_PATCHSET_REVISION} --json
"""
}
Example json file:
{
"labels": {
"Code-Style": "-1"
},
"message": "Lint Bot Review\nLint Results:\n Errors: 0\n Warnings: 0\n\nWhitespace results:\n Errors: 1",
"robot_comments": {
"Jenkinsfile": [
{
"robot_id": "lint-bot",
"line": "8",
"message": "trailing whitespace."
}
]
}
}
Alternatively, you may want to look at a new gerrit-code-review-plugin that should make this things even easier. However, I have not tried this yet.