I am learning Jenkins Pipeline, and I tried to follow this Pipeline code. But my Jenkins always complains that def is not legal.
I am wondering did I miss any plugins? I already installed groovy, job-dsl, but it doesn't work.
3 Answers
As @Rob said, There are 2 types of pipelines: scripted and declarative. It is like imperative vs declarative. def is only allowed in scripted pipeline or wrapped in script {}.
Scripted pipeline (Imperative)
Start with node, and def or if is allowed, like below. It is traditional way.
node { stage('Example') { if (env.BRANCH_NAME == 'master') { echo 'I only execute on the master branch' } else { echo 'I execute elsewhere' } } } Declarative pipeline (Preferred)
Start with pipeline, and def or if is NOT allowed, unless it is wrapped in script {...}. Declarative pipeline make a lot things easy to write and read.
time trigger
pipeline { agent any triggers { cron('H 4/* 0 0 1-5') } stages { stage('Example') { steps { echo 'Hello World' } } } } when
pipeline { agent any stages { stage('Example Build') { steps { echo 'Hello World' } } stage('Example Deploy') { when { branch 'production' } steps { echo 'Deploying' } } } } Parallel
pipeline { agent any stages { stage('Non-Parallel Stage') { steps { echo 'This stage will be executed first.' } } stage('Parallel Stage') { when { branch 'master' } failFast true parallel { stage('Branch A') { agent { label "for-branch-a" } steps { echo "On Branch A" } } stage('Branch B') { agent { label "for-branch-b" } steps { echo "On Branch B" } } } } } } embedded with scripted code
pipeline { agent any stages { stage('Example') { steps { echo 'Hello World' script { def browsers = ['chrome', 'firefox'] for (int i = 0; i < browsers.size(); ++i) { echo "Testing the ${browsers[i]} browser" } } } } } } To read more declarative pipeline grammar, please refer the official doc here
1 Comment
krad
See my example of it above as an alternative way to use it on a declarative pipeline
You can use def with a declarative pipeline, just not inside it eg
def agentLabel if (BRANCH_NAME =~ /^(staging|master)$/) { agentLabel = "prod" } else { agentLabel = "master" } pipeline { agent { node { label agentLabel } } .. 
Comments
You can use def by using node like below:
node { stage('Example') { if (env.BRANCH_NAME == 'master') { echo 'I only execute on the master branch' } else { echo 'I execute elsewhere' } } Another way : by using script{..}
stage ('jon'){ steps{ script{ def imageLine = 'chiducaff/user_containers:sonnginx' } writeFile file: 'anchore_images', text: imageLine anchore name: 'anchore_images' }} 
1 Comment
okapi
The latter form doesn't work. It seems you have to use the variable within the
script block or you get groovy.lang.MissingPropertyException for it.
defis valid.defis used in scripted pipeline, which start withnode {...}; while my file starts withpipeline, which is declarative, anddefis not allowed, unless it is wrapped byscript {...}