How do I pass variables between stages in a declarative Jenkins pipeline?
JenkinsJenkins PipelineJenkins Problem Overview
How do I pass variables between stages in a declarative pipeline?
In a scripted pipeline, I gather the procedure is to write to a temporary file, then read the file into a variable.
How do I do this in a declarative pipeline?
E.g. I want to trigger a build of a different job, based on a variable created by a shell action.
stage("stage 1") {
steps {
sh "do_something > var.txt"
// I want to get var.txt into VAR
}
}
stage("stage 2") {
steps {
build job: "job2", parameters[string(name: "var", value: "${VAR})]
}
}
Jenkins Solutions
Solution 1 - Jenkins
If you want to use a file (since a script is the thing generating the value you need), you could use readFile
as seen below. If not, use sh
with the script
option as seen below:
// Define a groovy local variable, myVar.
// A global variable without the def, like myVar = 'initial_value',
// was required for me in older versions of jenkins. Your mileage
// may vary. Defining the variable here maybe adds a bit of clarity,
// showing that it is intended to be used across multiple stages.
def myVar = 'initial_value'
pipeline {
agent { label 'docker' }
stages {
stage('one') {
steps {
echo "1.1. ${myVar}" // prints '1.1. initial_value'
sh 'echo hotness > myfile.txt'
script {
// OPTION 1: set variable by reading from file.
// FYI, trim removes leading and trailing whitespace from the string
myVar = readFile('myfile.txt').trim()
}
echo "1.2. ${myVar}" // prints '1.2. hotness'
}
}
stage('two') {
steps {
echo "2.1 ${myVar}" // prints '2.1. hotness'
sh "echo 2.2. sh ${myVar}, Sergio" // prints '2.2. sh hotness, Sergio'
}
}
// this stage is skipped due to the when expression, so nothing is printed
stage('three') {
when {
expression { myVar != 'hotness' }
}
steps {
echo "three: ${myVar}"
}
}
}
}
Solution 2 - Jenkins
Simply:
pipeline {
parameters {
string(name: 'custom_var', defaultValue: '')
}
stage("make param global") {
steps {
tmp_param = sh (script: 'most amazing shell command', returnStdout: true).trim()
env.custom_var = tmp_param
}
}
stage("test if param was saved") {
steps {
echo "${env.custom_var}"
}
}
}
Solution 3 - Jenkins
I had a similar problem as I wanted one specific pipeline to provide variables and many other ones using it to get this variables.
I created a my-set-env-variables pipeline
script
{
env.my_dev_version = "0.0.4-SNAPSHOT"
env.my_qa_version = "0.0.4-SNAPSHOT"
env.my_pp_version = "0.0.2"
env.my_prd_version = "0.0.2"
echo " My versions [DEV:${env.my_dev_version}] [QA:${env.my_qa_version}] [PP:${env.my_pp_version}] [PRD:${env.my_prd_version}]"
}
I can reuse these variables in a another pipeline my-set-env-variables-test
script
{
env.dev_version = "NOT DEFINED DEV"
env.qa_version = "NOT DEFINED QA"
env.pp_version = "NOT DEFINED PP"
env.prd_version = "NOT DEFINED PRD"
}
stage('inject variables') {
echo "PRE DEV version = ${env.dev_version}"
script
{
def variables = build job: 'my-set-env-variables'
def vars = variables.getBuildVariables()
//println "found variables" + vars
env.dev_version = vars.my_dev_version
env.qa_version = vars.my_qa_version
env.pp_version = vars.my_pp_version
env.prd_version = vars.my_prd_version
}
}
stage('next job') {
echo "NEXT JOB DEV version = ${env.dev_version}"
echo "NEXT JOB QA version = ${env.qa_version}"
echo "NEXT JOB PP version = ${env.pp_version}"
echo "NEXT JOB PRD version = ${env.prd_version}"
}
Solution 4 - Jenkins
I have enhanced the existing solution by correcting syntax .Also used hidden parameter plugin so that it does not show up as an extra parameter in Jenkins UI. Works well :)
properties([parameters([[$class: 'WHideParameterDefinition', defaultValue: 'yoyo', name: 'hidden_var']])])
pipeline {
agent any
stages{
stage("make param global") {
steps {
script{
tmp_param = "Hello"
env.custom_var = tmp_param
}
}
}
stage("test if param was saved") {
steps {
echo"About to check result"
echo "${env.custom_var}"
}
}
}
}