Schedule Jenkins job using Jenkins Rest API - jenkins

Question

I have a Jenkins job which is scheduled for a specific time. I want to modify that timing programmatically.
I tried to modify the build by installing Schedule Build plugin and modify it using http://jenkins_url/job/jobname/build?delay=3344sec. But this will put the job in quiet period which holds the java thread. I'm looking to modify the Schedule entry without putting it to quiet period.

Answer 1

You can use the Build Triggers -> Build periodically job configuration option. Use that to specify the exact time for starting a new build.
If you need to change that time, use the Jenkins REST API to...
programmatically retrieve the job configuration in XML format, then
modify the scheduling time in that configuration (see below)
re-post the new job configuration
In bash, this can be done with a one-liner (using curl and sed) to modify the XML section below (the example schedules a run for noon, Feb 29):
[...]
<triggers>
<hudson.triggers.TimerTrigger>
<spec>00 12 29 02 * </spec>
</hudson.triggers.TimerTrigger>
</triggers>
[...]
Note:
as a plus you wouldn't depend on any supplementary plugins
caveat: you cannot specify a year in the schedule -- so if you need to schedule builds more than one year in advance then you need some magic on top.

Answer 2

I can't get it to work, but the source code for the plugin references a "schedule" url action and a "date" param.
I tried something like:
http://localhost:8080/job/jobname/job/develop/schedule?date=2020-02-20
Which it didn't reject but I can't see a build.
below is the source code of the action performed when the button is pressed to schedule:
var newRequest = function() {
if (window.XMLHttpRequest) {
return new XMLHttpRequest();
} else {
return new ActiveXObject("Microsoft.XMLHTTP");
}
}
var sumbitScheduleRequest = function(absoluteUrl, quietPeriodInSeconds, isJobParameterized){
if(isJobParameterized){
// if job has parameters, redirect to build page, so user can set parameters
window.location = absoluteUrl + "build?delay=" + quietPeriodInSeconds + "sec";
}else{
// if job has NO parameters, submit build directly
var csrfCrumb;
var csrfRequest = newRequest();
csrfRequest.onreadystatechange = function() {
if (csrfRequest.readyState === 4) {
if (csrfRequest.status === 200 || csrfRequest.status === 201) {
csrfCrumb = JSON.parse(csrfRequest.responseText);
} else {
// csrf might be deactivated
}
// do the actual submit
var xmlhttp = newRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState === 4) {
if (xmlhttp.status === 200 || xmlhttp.status === 201) {
window.location = absoluteUrl;
return false;
} else {
window.location = absoluteUrl;
return false;
}
}
};
xmlhttp.open("POST", absoluteUrl + "build?delay=" + quietPeriodInSeconds + "sec", true);
if (csrfCrumb) {
xmlhttp.setRequestHeader(csrfCrumb.crumbRequestField, csrfCrumb.crumb)
}
xmlhttp.send();
}
};
csrfRequest.open('GET', rootURL + '/crumbIssuer/api/json', false);
csrfRequest.send();
}
}