How can I retrieve dynamically-named stashes in a Jenkins pipeline? - jenkins

Question

I have a Jenkins pipeline, which runs a suite of automated tests against a variety of environments in separate workers using the matrix directive. At the end of this, I would like to combine the code coverage output of the various test suite runs into a single file before collecting them, to ensure that the results are accurate. This sounds like it should be simple:
For each matrix cell, stash the coverage output file with a unique stash name, based on the matrix cell values.
After the test runs are complete, unstash all of the files on the "main" worker and combine them.
However, the fact that the stashes are dynamically named makes step 2 difficult. This leaves me, seemingly, with three options:
Hardcode the matrix axes again when unstashing. Not particularly appealing.
Retrieve the matrix axes programmatically. It seems like it should be possible, but I'm uncertain how to go from the FlowNodeWrapper representing the matrix stage to the underlying axis strings.
List all stashes for the build, and pick the ones I want. Also a viable solution if it's possible, since the stash names follow a pattern, but I'm not even sure where to start with this one. There is an open issue related to this in the Jenkins issue board, but it doesn't seem like it'll be moving anytime soon.
In short: how can I achieve this? How can I either:
Go from a FlowNodeWrapper to the matrix axes?
Find my stashes in a different way?

Answer 1

1. For each matrix cell, stash the coverage output file with a unique stash name, based on the matrix cell values.
Right. I'm not familiar with matrix, so I don't know for sure how you can get a unique name, but in many cases you can use env.STAGE_NAME.
2. After the test runs are complete, unstash all of the files on the "main" worker and combine them.
In step 1, keep track of the stash names you've used. Then step 2 is easy.
With a scripted pipeline, that's easy:
def stashes = [:]
…
stage(…) {
…
String stash_name = env.STAGE_NAME
stash stash_name, …
stashes[stash_name] = 1
}
…
stage('Coverage analysis') {
for (stash_name in stashes) {
unstash stash_name
}
…
}
I don't know if that works with a declarative pipeline.