How to lock multiple stages of declarative Jenkins pipeline?

Question

I want to run multiple stages inside a lock within a declarative Jenkins pipeline:

pipeline {
    agent any
    stages {
        lock(resource: 'myResource') {
            stage('Stage 1') {
                steps {
                  echo "my first step"
                }
            }

            stage('Stage 2') {
                steps {
                  echo "my second step"
                }
            }

        }
    }
}

I get the following error:

Started by user anonymous
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
WorkflowScript: 10: Expected a stage @ line 10, column 9.
           lock(resource: 'myResource') {
           ^

WorkflowScript: 10: Stage does not have a name @ line 10, column 9.
           lock(resource: 'myResource') {
           ^

WorkflowScript: 10: Nothing to execute within stage "null" @ line 10, column 9.
           lock(resource: 'myResource') {
           ^

3 errors

    at org.codehaus.groovy.control.ErrorCollector.failIfErrors(ErrorCollector.java:310)
    at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1085)
    at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:603)
    at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:581)
    at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:558)
    at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:298)
    at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:268)
    at groovy.lang.GroovyShell.parseClass(GroovyShell.java:688)
    at groovy.lang.GroovyShell.parse(GroovyShell.java:700)
    at org.jenkinsci.plugins.workflow.cps.CpsGroovyShell.reparse(CpsGroovyShell.java:116)
    at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.parseScript(CpsFlowExecution.java:430)
    at org.jenkinsci.plugins.workflow.cps.CpsFlowExecution.start(CpsFlowExecution.java:393)
    at org.jenkinsci.plugins.workflow.job.WorkflowRun.run(WorkflowRun.java:257)
    at hudson.model.ResourceController.execute(ResourceController.java:97)
    at hudson.model.Executor.run(Executor.java:405)
Finished: FAILURE

What's the problem here? The documentation explicitly states:

lock can be also used to wrap multiple stages into a single concurrency unit

Answer 1

The problem is that, despite the fact that declarative pipelines were technically available in beta in September, 2016, the blog post you reference (from October) is documenting scripted pipelines, not declarative (it doesn't say as much, so I feel your pain). Lockable resources hasn't been baked in as a declarative pipeline step in a way that would enable the feature you're looking for yet.

You can do:

pipeline {
  agent { label 'docker' }
  stages {
    stage('one') {
      steps {
        lock('something') {
          echo 'stage one'
        }
      }
    }
  }
}

But you can't do:

pipeline {
  agent { label 'docker' }
  stages {
    lock('something') {
      stage('one') {
        steps {
          echo 'stage one'
        }
      }
      stage('two') {
        steps {
          echo 'stage two'
        }
      }
    }
  }
}

And you can't do:

pipeline {
  agent { label 'docker' }
  stages {
    stage('one') {
      lock('something') {
        steps {
          echo 'stage one'
        }
      }
    }
  }
}

You could use a scripted pipeline for this use case.

Answer 2

It should be noted that you can lock all stages in a pipeline by using the lock option:

pipeline {
    agent any
    options {
        lock resource: 'shared_resource_lock'
    }
    stages {
        stage('will_already_be_locked') {
            steps {
                echo "I am locked before I enter the stage!"
            }
        }
        stage('will_also_be_locked') {
            steps {
                echo "I am still locked!"
            }
        }
    }
}

Answer 3

This has been fixed.

You can now lock multiples stages by grouping them in a parent stage, like this :

stage('Parent') {
  options {
    lock('something')
  }
  stages {
    stage('one') {
      ...
    }
    stage('two') {
      ...
    }
  }
}

(Don't forget you need the Lockable Resources Plugin)

Answer 4

If the resource is only used by this pipeline you could also disable concurrent builds:

pipeline {
    agent any
    options {
        disableConcurrentBuilds()
    }
    stages {
        stage('will_already_be_locked') {
            steps {
                echo "I am locked before I enter the stage!"
            }
        }
        stage('will_also_be_locked') {
            steps {
                echo "I am still locked!"
            }
        }
   }
}