Multiconfiguration / matrix build pipeline in Jenkins - jenkins

Question

What is modern best practice for multi-configuration builds (with Jenkins)?
I want to support multiple branches and multiple configurations.
For example for each version V1, V2 of the software I want builds targeting
platforms P1 and P2.
We have managed to set up multi-branch declarative pipelines. Each build has its own docker so its easy to support multiple platforms.
pipeline {
agent none
stages {
stage('Build, test and deploy for P1) {
agent {
dockerfile {
filename 'src/main/docker/Jenkins-P1.Dockerfile'
}
}
steps {
sh buildit...
}
}
stage('Build, test and deploy for P2) {
agent {
dockerfile {
filename 'src/main/docker/Jenkins-P2.Dockerfile'
}
}
steps {
sh buildit...
}
}
}
}
This gives one job covering multiple platforms but there is no separate red/blue status for each platform.
There is good argument that this does not matter as you should not release unless the build works for all platforms.
However, I would like a separate status indicator for each configuration. This suggests I should use a multi-configuration build which triggers a parameterised build for each configuration as below (and the linked question):
pipeline {
parameters {
choice(name: 'Platform',choices: ['P1', 'P2'], description: 'Target OS platform', )
}
agent {
filename someMagicToGetDockerfilePathFromPlatform()
}
stages {
stage('Build, test and deploy for P1) {
steps {
sh buildit...
}
}
}
}
There are several problems with this:
A declarative pipeline has more constraints over how it is scripted
Multi-configuration builds cannot trigger declarative pipelines (even with the parameterized triggers plugin I get "project is not buildable").
This also begs the question what use are parameters in declarative pipelines?
Is there a strategy that gives the best of both worlds i.e:
pipeline as code
separate status indicators
limited repetition?

Answer 1

This is a partial answer. I think others with better experience will be able to improve on it.
This is currently untested. I may be barking up the wrong tree.
Please comment or add a better answer.
Do not use pipeline parameters except where you need user input
Use a hybrid of a scripted and declarative pipeline
(see also https://stackoverflow.com/a/46675227/1569204)
Have a function which declares a pipeline based on parameters:
(see also https://jenkins.io/doc/book/pipeline/shared-libraries/)
Use nodes to create visible indicators in the pipeline (at least in blue ocean)
So something like the following:
def build(string platform) {
switch(platform) {
case P1:
dockerFile = 'foo'
indicator = 'build for foo'
break
case P2:
dockerFile = 'bar'
indicator = 'build for bar'
break
}
pipeline {
agent {
dockerfile {
filename "$dockerFile"
}
node {
label "$indicator"
}
}
stages {
steps {
echo "build it"
}
}
}
}
The relevant code could be moved to a shared library (even if you don't actually need to share it).

Answer 2

I think the cleanest approach is to have this all in a pipeline similar to the first one you presented, the only modification I would see here is making those parallel, so you would actually try and build/test for both platforms.
To reuse the previous stage's workspace you could do: reuseNode true
Something similar to this flow, that would have parallel build for platforms
pipeline {
agent 'docker'
stages {
stage('Common pre') { ... }
stage('Build all platforms') {
parallel {
stage('Build, test and deploy for P1') {
agent {
dockerfile {
filename 'src/main/docker/Jenkins-P1.Dockerfile'
reuseNode true
}
}
steps {
sh buildit...
}
}
stage('Build, test and deploy for P2') {
agent {
dockerfile {
filename 'src/main/docker/Jenkins-P2.Dockerfile'
reuseNode true
}
}
steps {
sh buildit...
}
}
}
}
stage('Common post parallel') { ... }
}
}