use of bash env variable in post section of pipeline - bash

Question

I have been reading as many posts as possible about this topic but none of them suggest working solutions for me, so, throwing it again to the community:
In a Jenkinsfile pipeline I have
steps {
(...)
sh script: '''
$pkgname #existing var
export report_filename=$pkgname'_report.txt'
(stuff is being written to the $report_filename file...)
'''
}
post {
always {
script {
//want to read the file with name carried by $report_filename
def report = readFile(file: env.report_filename, encoding: 'utf-8').trim()
buildDescription(report)
}
}
}
I don't manage to pass the value of the report_filename bash var on to the post > always > script section. Tried ${env.report_filename} (with/without single/double quotes), with/without env. and some other crazy things.
What am I doing wrong here?
Thanks.

Answer 1

May by it little bit not right.
create variable def var
use options returnStdout: true. And parse output. var = sh ( script " echo #existing var", returnStdout: true).split("\n")
use var[0] in stage readFile(file: var[0]...)
If u can use env, add:
environment {
VAR = sh (script " echo #existing var", returnStdout: true).split("\n") [0]
}
script {
//want to read the file with name carried by $report_filename
def report = readFile(file: env.VAR , encoding: 'utf-8').trim()
buildDescription(report)
}

Answer 2

I don't see why you don't simply declare the variables in Groovy right at the start.
I'm not too familiar with the language, and don't currently have a way to test this; but something like this:
def pkgname = "gunk"
def report_filename = "${pkgname}_report.txt"
steps {
(...)
sh script: """
# use triple double quotes so that Groovy variables are interpolated
# $pkgname #syntax error, take it out
(stuff is being written to the $report_filename file...)
"""
}
post {
always {
script {
//want to read the file with name carried by $report_filename
def report = readFile(file: env.report_filename, encoding: 'utf-8').trim()
buildDescription(report)
}
}
}