Parallel execution inside the post step - jenkins

Question

I am building to 2 different environments in the same pipeline and I want to make the cleanup for both environments in parallel.
As I understood, parallel does not work inside the post step: post step parallel.
Any suggestions? Example of my code:
post {
always {
script{
cleanup(env1)
cleanup(env2)
}
}
}
def cleanup(env) {
withEnv(env) {
sh "./cleanup.py"
}
}

Answer 1

The parallel keyword can work inside a post condition as long as it is encapsulated inside a script block, as the script blocks is just a fallback to the scripted pipeline which will allow you to run parallel execution wherever you want.
The following should work fine:
post {
always{
script {
def environments = ['env1', 'env2', 'env3']
parallel environments.collectEntries {
["Cleanup ${it}" : {
cleanup(it)
}]
}
}
}
}
def cleanup(env) {
withEnv(env) {
sh "./cleanup.py"
}
}
Just don't forget to allocate an agent using the node keyword if the steps in the post section are required to run on a specific agent.

Answer 2

A better idea in my opinion is to clean up after the fact, before you possibly lost the node to another job:
parallel {
stage('env1') {
agent { node { label "env1" }}
steps {
script {
println "Inside env1"
}
}
post {
cleanup { script { my_cleanup_func("env1") } }
}
}
stage('env2') {
agent { node { label "env2" }}
steps {
script {
println "Inside env2"
}
}
post {
cleanup { script { my_cleanup_func("env2") } }
}
}
...
def my_cleanup_func(String env) {
// ...
}