How do I pass variables between stages in a declarative Jenkins pipeline?

Question

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})]     } } 

Answer 1

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}"       }     }   } } 

Answer 2

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}"             }         }   }