Dcron package

The dcron package is a distributed cron job scheduling system designed to run scheduled tasks across multiple nodes in a cluster. It leverages Redis as a backend for job storage and synchronization among nodes. Here's a detailed breakdown of its functionality and components:

Core Features

• Distributed Execution: dcron allows cron jobs to be executed in a distributed manner across multiple nodes, ensuring high availability and scalability.
• Job and JobWarpper: Defines the interface for jobs and a wrapper that includes scheduling information and execution logic.
• RecentJobPacker: Manages recently executed jobs, useful for recovering state after cluster changes.
• Driver: Interface for backend storage, with a Redis implementation provided for job synchronization across nodes.

Usage

Step 1: Define a Job

First, you need to define a job by implementing the Job interface. A job must have a Run method that contains the logic to be executed.

type MyJob struct {
    // Add any fields you need here
}

func (job *MyJob) Run() {
    // Job execution logic goes here
    fmt.Println("Job is running!")
}

Step 2: Initialize dcron

Next, create a new dcron instance, configure it with a Redis driver for synchronization, and set up any additional options you need.

redisCli := redis.NewClient(&redis.Options{
    Addr: "localhost:6379", // Replace with your Redis server address
})

driver := driver.NewRedisDriver(redisCli)

dcronInstance := dcron.NewDcronWithOption(
    "myServerName",
    driver,
    dcron.WithLogger(logger.DefaultPrintfLogger()),
    dcron.WithHashReplicas(10),
    dcron.WithNodeUpdateDuration(time.Second*10),
)

Step 3: Add a Job

Finally, start the dcron instance to begin executing scheduled jobs.

job := &MyJob{}
err := dcronInstance.AddJob("myJob", "*/5 * * * *", job) // Runs every 5 minutes
if err != nil {
    log.Fatalf("Error adding job to dcron: %v", err)
}

Step 4: Start dcron

Finally, start the dcron instance to begin executing scheduled jobs.

// you can use Start() or  Run() to start the dcron instance.

// unblocking start
dcronInstance.Start()

// blocking start
dcronInstance.Run()

Example

• examples