[JENKINS-67725] Need to be able to customize BranchBuildStrategies to not build in the future. Not just a one time evaluataion.

[jenkins-infra-bot]

The use case:

• Imagine I want to have an ephemeral Jenkins (Docker/K8S/etc).
• I want it to be preconfigured with multibranch pipelines and/or Github/Bitbucket organization folders.
• I want it to come online and when it does, it will scan for unknown repositories and branches and cause a build storm.

 

• The Problem as I see it: 
  1. There are many plugins out there who try to deal with this, but none of them work fully.
     • Build Strategy - https://github.com/jenkinsci/basic-branch-build-strategies-plugin/blob/master/src/main/java/jenkins/branch/buildstrategies/basic/SkipInitialBuildOnFirstBranchIndexing.java
       • Doesnt fully work because the next time indexing runs - it builds.  So it delays the build storm.
  2. There are active PRs/Comments working to try to solve it different ways.
     • https://issue-redirect.jenkins.io/issue/38552?focusedCommentId=289692&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-289692
     • [JENKINS-63673] Allow configuring suppressed events in NoTrigger properties #244
       • Solves some of it - but still assumes every webhook is delivered
       • Their discussion - prevent building branches/PRs existing before the first branch indexing #186 

 

I think the requirements are relatively simple and so is the implementation:

• Here is where all branches come in the front door
• It will always hit `observeNew` first.
  • We can use a BuildStrategy to not run any build that has a commit older than some EPOCH time.
• The next time a webhook/index comes in it hits `observeExisting`
  • Most times I notice it hits
    • if (changesDetected(revision, project, scmLastBuiltRevision)) {
  • changesDetected only evaluates last built revision. Problem 1
  • And it always hits lastSeenRevisionOrDefault which saves last seen revision
  • _factory.setLastSeenRevisionHash(project, scmLastBuiltRevision);
• So we should be able to do this in a 2 step process.
  1. Add build strategy that refuses to build if commit ID is not after a starting time (easily programmed on jenkins master startup)
  2. Have the branch-api-plugin have an option to save lastseenrevision as lastbuilt revision.

 

#1 - Is a little harder since we are not handed any kind of probe so we have to hit Github right now (API) (More unnecessary API calls).  But it does stop the build.  In #2 I added SCMEvent as an extension of BuildBranchStrategy that allows us to see time of commit to help make less API calls to github.

#2 - A literal property/config item - copy/boolean for when lastSeenRevisionOrDefault is called - also call  setRevisionHash on the same factory.  So if we have seen it (assume built).  (Is there anything wrong with this design?). Feature Flag?  Another option is to impact how `changesDetected` works or make it extendable.

• [JENKINS-32396] Make triggering per-branch projects optional  #1 - 
• Make triggering per-branch projects use the SCMTriggerCause. #2 - JENKINS-67725 - Extending BranchBuildStrategies to allow setting last revision built + access to SCMEvent #291

 

I will start on #1

---

Originally reported by carpnick2, imported from: Need to be able to customize BranchBuildStrategies to not build in the future. Not just a one time evaluataion.

• status: Open
• priority: Minor
• component(s): branch-api-plugin
• resolution: Unresolved
• votes: 0
• watchers: 2
• imported: 20251211-141027

Raw content of original issue

The use case:

	
Imagine I want to have an ephemeral Jenkins (Docker/K8S/etc).
	
I want it to be preconfigured with multibranch pipelines and/or Github/Bitbucket organization folders.
	
I want it to come online and when it does, it will scan for unknown repositories and branches and cause a build storm.



 

	
The Problem as I see it: 
	

		
There are many plugins out there who try to deal with this, but none of them work fully.
		

			
Build Strategy - https://github.com/jenkinsci/basic-branch-build-strategies-plugin/blob/master/src/main/java/jenkins/branch/buildstrategies/basic/SkipInitialBuildOnFirstBranchIndexing.java
			

				
Doesnt fully work because the next time indexing runs - it builds.  So it delays the build storm.
			
			
		
		
		
There are active PRs/Comments working to try to solve it different ways.
		

			
https://issues.jenkins.io/browse/JENKINS-38552?focusedCommentId=289692&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-289692
			
[JENKINS-63673] Allow configuring suppressed events in NoTrigger properties #244
			

				
Solves some of it - but still assumes every webhook is delivered
				
Their discussion - prevent building branches/PRs existing before the first branch indexing #186 
				

			
			
		
		
	
	



 

I think the requirements are relatively simple and so is the implementation:

	
Here is where all branches come in the front door
	
It will always hit `observeNew` first.
	

		
We can use a BuildStrategy to not run any build that has a commit older than some EPOCH time.
	
	
	
The next time a webhook/index comes in it hits `observeExisting`
	

		
Most times I notice it hits
		

			
if (changesDetected(revision, project, scmLastBuiltRevision)) {
		
		
		
changesDetected only evaluates last built revision. Problem 1
		
And it always hits lastSeenRevisionOrDefault which saves last seen revision
		
_factory.setLastSeenRevisionHash(project, scmLastBuiltRevision);
	
	
	
So we should be able to do this in a 2 step process.
	

		
Add build strategy that refuses to build if commit ID is not after a starting time (easily programmed on jenkins master startup)
		
Have the branch-api-plugin have an option to save lastseenrevision as lastbuilt revision.
	
	



 

#1 - Is a little harder since we are not handed any kind of probe so we have to hit Github right now (API) (More unnecessary API calls).  But it does stop the build.  In #2 I added SCMEvent as an extension of BuildBranchStrategy that allows us to see time of commit to help make less API calls to github.

#2 - A literal property/config item - copy/boolean for when lastSeenRevisionOrDefault is called - also call  setRevisionHash on the same factory.  So if we have seen it (assume built).  (Is there anything wrong with this design?). Feature Flag?  Another option is to impact how `changesDetected` works or make it extendable.

	
#1 - 
	
#2 - JENKINS-67725 - Extending BranchBuildStrategies to allow setting last revision built + access to SCMEvent #291



 

I will start on #1

[jenkins-infra-bot]

pimsierhuis:

• Original comment link
• Raw content of original comment:

  Wouldn't it be cleaner to store the revision during first indexing and pass that to the branch strategy, so the branch strategy can decide not to build when revison.equals(revisionDuringFirstIndexingHash)?
  
  Proof of concept here (without the passing to the branch strategy):
  
  https://github.com/pimsierhuis/branch-api-plugin/tree/revisionDuringFirstIndexing
  
   
  

Wouldn't it be cleaner to store the revision during first indexing and pass that to the branch strategy, so the branch strategy can decide not to build when revison.equals(revisionDuringFirstIndexingHash)?

Proof of concept here (without the passing to the branch strategy):

https://github.com/pimsierhuis/branch-api-plugin/tree/revisionDuringFirstIndexing

 

[jenkins-infra-bot]

carpnick2:

• Original comment link
• Raw content of original comment:

  pimsierhuis - Yes, probably cleaner for the first requirement.  My thought on sending in the SCMEvent, it would open up this specific use case, and allows the rest of the code in `MultiBranchProject` to be mostly untouched.  Also, I was thinking if anyone else has other use cases where they want to selectively build based on what is in SCMEvent, this would allow them to create other extensions in the future.
  

pimsierhuis - Yes, probably cleaner for the first requirement.  My thought on sending in the SCMEvent, it would open up this specific use case, and allows the rest of the code in `MultiBranchProject` to be mostly untouched.  Also, I was thinking if anyone else has other use cases where they want to selectively build based on what is in SCMEvent, this would allow them to create other extensions in the future.

[jenkins-infra-bot]

pimsierhuis:

• Original comment link
• Raw content of original comment:

  Well we can still pass the SCMEvent in too I guess. Just found it cleaner that the BuildStrategy gets all data it needs passed in at once, as in your approach it needs to store some information to answer the updatingLastBuiltRevisionWithNoBuild() call.
  
  What I'm also wondering (I just don't understand you solution completely I guess), is how you'll let the updatingLastBuiltRevisionWithNoBuild() call return true only for the revision during setup of the project.
  
  Also, that extra method complicates the concept behind things like AllBranchBuildStrategyImpl and AnyBranchBuildStrategyImpl. 
  

Well we can still pass the SCMEvent in too I guess. Just found it cleaner that the BuildStrategy gets all data it needs passed in at once, as in your approach it needs to store some information to answer the updatingLastBuiltRevisionWithNoBuild() call.

What I'm also wondering (I just don't understand you solution completely I guess), is how you'll let the updatingLastBuiltRevisionWithNoBuild() call return true only for the revision during setup of the project.

Also, that extra method complicates the concept behind things like AllBranchBuildStrategyImpl and AnyBranchBuildStrategyImpl.