[JENKINS-51879] Scan Repository Trigger Periodically : configurable crontab (`spec`)

Currently we can only choose a period, which is then used to define a crontab (https://github.com/jenkinsci/cloudbees-folder-plugin/blob/7e6294bc48d4cddc89c129ceaf1ab6d352462425/src/main/java/com/cloudbees/hudson/plugins/folder/computed/PeriodicFolderTrigger.java#L117).

For example: 1 day period => `H H 0 0 0` crontab:

```

H H * * *

86400000

```

 

Feature request: Make `spec`/crontab configurable via GUI.

Goal: re-scan only at night, because it can trigger a lot of builds, filling Jenkins build queue.

Scenario:

• Lots of pending PR on github


• Jenkins config: build PR by merging target branch first


• New commits on target branch

=> an automatic re-scan mid-day triggers a re-build of all pending PR, saturating the Jenkins cluster for may hours.

 

What I tried:

Manually edit the `config.xml` file, reloading the config from disk on Jenkins: Modification gets lost on next GUI save, overwritten by a static value determined from period.

---
Originally reported by thomas_deepomatic, imported from: Scan Repository Trigger Periodically : configurable crontab (`spec`)

• status: Open
  
• priority: Minor
  
• component(s): cloudbees-folder-plugin
  
• label(s): configuration, user-experience
  
• resolution: Unresolved
  
• votes: 5
  
• watchers: 6
  
• imported: 20251211-141027
  

Raw content of original issue

Currently we can only choose a period, which is then used to define a crontab (https://github.com/jenkinsci/cloudbees-folder-plugin/blob/7e6294bc48d4cddc89c129ceaf1ab6d352462425/src/main/java/com/cloudbees/hudson/plugins/folder/computed/PeriodicFolderTrigger.java#L117).


For example: 1 day period => `H H 0 0 0` crontab:


```


<triggers>

 <com.cloudbees.hudson.plugins.folder.computed.PeriodicFolderTrigger plugin="cloudbees-folder@6.4">

 <spec>H H * * *</spec>

 <interval>86400000</interval>

 </com.cloudbees.hudson.plugins.folder.computed.PeriodicFolderTrigger>

 </triggers>


```


 


Feature request: Make `spec`/crontab configurable via GUI.


Goal: re-scan only at night, because it can trigger a lot of builds, filling Jenkins build queue.


Scenario:



	
Lots of pending PR on github

	
Jenkins config: build PR by merging target branch first

	
New commits on target branch



=> an automatic re-scan mid-day triggers a re-build of all pending PR, saturating the Jenkins cluster for may hours.


 


What I tried:


Manually edit the `config.xml` file, reloading the config from disk on Jenkins: Modification gets lost on next GUI save, overwritten by a static value determined from period.