gnmathur / saarekaam

Java based job scheduler

SaareKaam

Java based task scheduler

Introduction

SaareKaam (Saare=All and Kaam=work in Hindi), is task scheduler written in Java. It accepts the tasks to be scheduled in the form of a jar file. The aim of the project is to provide a simple, easy to use, and reliable task scheduler. It does not support a distributed mode. It is ideal for a use case where a user wants to schedule a bunch of tasks to run on a single machine. Tasks can range from simple to complex. For example, a task can be to download a file from the internet, or running a Postgres query, or calling an API etc. Since tasks can run concurrently, and there is no hard limit on the number of tasks that can be scheduled, the application does not support priority based scheduling.

Features

1. Different task scheduling options including one time, recurring, and cron based
2. Tasks are provided to the scheduler as a jar file at startup
3. Identifying long-running tasks and terminating them after a configurable timeout

Running the scheduler

Prerequisites

1. Java 17
2. Maven 3.8.2

Building the scheduler and running it

The current repository has a coupled of test tasks. The scheduler can be run using the following command to load those test tasks:

mvn package && java -Xmx512M -DlogLevel=INFO -javaagent:ext/lib/jmx_prometheus_javaagent-0.20.0.jar=8899:ext/lib/prometheus_jmx_config.yml -jar target/saarekaam-1.0-SNAPSHOT-jar-with-dependencies.jar target/saarekaam-1.0-SNAPSHOT-jar-with-dependencies.jar 

You can also build and run it as a Docker container

docker build -t <name>:<version> .

docker run -it --rm -p 8899:8899 <name>:<version>

Note: For convenience, both the core scheduler and the test task classes are in the same jar file. In production, the tasks will be provided as a separate jar file.