ballerina/task Ballerina library

Overview

This module provides APIs to schedule a Ballerina job either once or periodically and to manage the execution of those jobs.

Jobs and scheduling

Every scheduling job in Ballerina needs to be represented by a Job object. Therefore, a job class with your custom logic needs to be created to execute it when the task is triggered.

The task package has the following two scheduling systems to schedule the job:

• One-time job execution
• Frequency-based job execution

One-time job execution

This API provides the functionality to schedule a job at a specified time.

The following code snippet shows how to schedule a one-time job.

class Job {

    *task:Job;
    string msg;

    public function execute() {
        io:println(self.msg);
    }

    isolated function init(string msg) {
        self.msg = msg;
    }
}

time:ZoneOffset zoneOffset = {
    hours: 5,
    minutes: 30,
    seconds: <decimal>0.0
};
time:Civil time = {
    year: 2021,
    month: 4,
    day: 13,
    hour: 4,
    minute: 50,
    second: 50.52,
    timeAbbrev: "Asia/Colombo",
    utcOffset: zoneOffset
};

task:JobId result = check task:scheduleOneTimeJob(new Job("Hi"), time);

Frequency-based job execution

This API provides the functionality to schedule jobs on a specific interval either once or periodically by configuring the configuration such as start time, end time, and maximum count.

The following code snippet shows how to schedule a recurring job by using this API.

class Job {

    *task:Job;
    string msg;

    public function execute() {
        io:println(self.msg);
    }

    isolated function init(string msg) {
        self.msg = msg;
    }
}

time:ZoneOffset zoneOffset = {
    hours: 5,
    minutes: 30
};
time:Civil time = {
    year: 2021,
    month: 3,
    day: 31,
    hour: 4,
    minute: 50,
    second: 50.52,
    timeAbbrev: "Asia/Colombo",
    utcOffset: zoneOffset
};

task:JobId result = check task:scheduleJobRecurByFrequency(new Job("Hi"), 2.5, maxCount = 10, startTime = time);

For information on the operations, which you can perform with the task module, see the below Functions.