[JIRA] (JENKINS-55485) Declarative pipeline, lock() in stage options is executed before when clause

Daniel.Pasto@gmail.com (JIRA)

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Jan 9, 2019, 10:24:02 AM1/9/19

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D Pasto updated an issue

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JENKINS-55485

Declarative pipeline, lock() in stage options is executed before when clause

Change By:	D Pasto
Summary:	Declarative pipeline, lock() in stage aoptions options is executed before when clause

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Daniel.Pasto@gmail.com (JIRA)

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Jan 9, 2019, 10:25:02 AM1/9/19

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D Pasto updated an issue

Jenkins /

JENKINS-55485

Declarative pipeline, lock() in stage options is executed before when clause

Change By:	D Pasto

In a a declarative pipeline i have a stage grouping several other stages and need to hold a lock for the duration of the group. I see I can add lock() to the options of the group and it works fine in that scenario. However the group also has a When clause so I can turn that group off with a job parameter.

The problem is that when the "when" evaluates false so the stage will be skipped, it wait for the lock anyway. If the stage will be skipped for any reason, we should not block on the lock. The "when" defines a "beforeAgent" attribute for a similar need, so that might be an approach, but I'm not seeing a scenario where you would want to do it in the current order.

My pipeline looks like:

--- —

pipeline {

agent none
stages {

stage ('Build') {

{ }

stage('Deploy-and-Test') { // Group Stage Deploy and test the Build - lock the deployment VM so we don't step on other runs
when {
expression {
"${params.Deploy}" == "true"
}
beforeAgent true
}
options {
lock(quantity: 1, resource: "${params.DeployAgent}", variable: 'myDeployAgent')
}
agent none

stages \{ ...}

}}}

When I run it withthe param to disable the stage I see:

--- —
[Pipeline] stage[Pipeline] { (Deploy-and-Test)[Pipeline] lockTrying to acquire lock on [DeploymentVM_Win]
Lock acquired on [DeploymentVM_Win][Pipeline] {Stage "Deploy-and-Test" skipped due to when conditional
--- —

Since the stage is being skipped there is no point in holding the lock, but it the lock is already allocated, this will block anyway. The lock() should be processed _after_ the decision whether to execute the stage.

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Daniel.Pasto@gmail.com (JIRA)

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Jan 17, 2019, 3:11:08 PM1/17/19

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D Pasto commented on

JENKINS-55485

Re: Declarative pipeline, lock() in stage options is executed before when clause

I verified the workaround of adding an additional level of stage - I have a group stage with the when clause containing a group stage with the lock, containing the actual stages. With this structure I'm able to use the when clause to disable deploy and test stages, and not get stuck waiting for a lock behind a long-running test.

The workaround is conceptually easy, but adds a lot of boilerplate and makes the Jenkinsfile that much harder to read. I'm now up to 10 levels of tabs in my Jenkinsfile and have a check-in with hundreds of lines of changes that is just indenting. It's getting pretty ugly.

This is exactly the mess the "beforeAgent" directive to the "when" clause prevents - we need a similar solution here.