How to disable "build now" option? - jenkins

Question

For a given scripted pipeline(jenkins), the pipeline should only get triggered through webhook from GitLab
Build Now option should be disabled for that pipeline.
Can we configure Jenkins, to disable Build Now option for a specific pipeline script job in jenkins?

Answer 1

EDIT: Here the solution with an scripted Pipeline:
node {
def userIdCause = currentBuild.getBuildCauses('hudson.model.Cause$UserIdCause')
stage("Authorize Usage") {
if (userIdCause.size()) {
error('Aborting Build due to manual start - thats not permitted!')
}
}
}
How about the following solution without any extra plugin on an declarative pipeline:
pipeline {
...
stages {
stage ("Authorize Usage") {
when { expression { getCause() == "USER" } }
steps {
currentBuild.description = 'Aborting Build due to manual start - thats not permitted!'
error('Aborting Build due to manual start - thats not permitted!')
}
}
...
}

Answer 2

Have taken a look at this plug-in supplied on the Jenkin's site? Matrix Authorization Strategy Plugin :
Matrix Strategy
Specifically this sectionL Allow configuring per-agent permissions. This allows e.g. restricting per-agent build permissions when using the Authorize Project plugin (JENKINS-46654)

Answer 3

Not ideal, but if this is a 'freestyle pipeline job'
a quick workaround is to add a build step "Execute shell" as first step. You can use this to prevent a build, when noting has changed.
Every time your sources changes and you push to your repo, a build will have been triggered and as there are changes this script will not exit.
When you click the 'Build now', nothing should have changed in your repo (as the only way it can is through a push which would then trigger a build) it will causes an exit, and fail the build.
if [[ $GIT_COMMIT -eq $GIT_PREVIOUS_COMMIT ]]
then
echo "Exiting build - Nothing has changed"
echo "This is to prevent the usage of Jenkins 'build now'"
exit 1
fi

Answer 4

EDIT: This is the answer to the question of user #mohet in the comments of my other answer because it was to long for the comment section (https://stackoverflow.com/a/55058788/7746963).
The currentBuild variable, which is of type RunWrapper, may be used to refer to the currently running build...
Source: https://opensource.triology.de/jenkins/pipeline-syntax/globals .
hudson.model is the package name of most corresponding core jenkins classes. 'Hudson' because jenkins was once cloned from the codebase of his ancestor named 'hudson'.
You can look up them here: https://javadoc.jenkins.io/hudson/model/package-summary.html .
There you will also find https://javadoc.jenkins.io/hudson/model/Cause.UserIdCause.html . To specify directly the package$classname in some methods like getbuildcauses is the straightforward thought of jenkins dev Team. This reduces the failure potential and makes the code better readable and understandable.