⏳taskflow

Taskflow is a lightweight Go library for running background jobs out of a MySQL queue table. It handles:

• Fetching jobs from the database
• Locking and retrying failed jobs
• Creating new jobs programmatically
• Running custom job logic with optional timeouts
• Structured logging via user-defined callbacks
• Graceful shutdown of worker pools

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Table of Contents

1. Installation
2. Database Schema
3. Quick Start Example
4. Contributing
5. License

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Installation

go get github.com/sky93/taskflow

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Database Schema

Your database should contain a jobs table. For example:

CREATE TABLE IF NOT EXISTS jobs (
  id BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
  operation VARCHAR(50) NOT NULL,
  status ENUM('PENDING','IN_PROGRESS','COMPLETED','FAILED') NOT NULL DEFAULT 'PENDING',
  payload JSON NULL,
  output JSON NULL,
  error_output JSON NULL,
  locked_by VARCHAR(50) NULL,
  locked_until DATETIME NULL,
  retry_count INT UNSIGNED NOT NULL DEFAULT 0,
  available_at DATETIME NOT NULL DEFAULT '1970-01-01 00:00:00',
  created_at DATETIME NOT NULL,
  updated_at DATETIME NOT NULL
);

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Quick Start Example

Below is a complete, minimal example showing:

1. Connecting to the database
2. Creating a taskflow.Config and a new TaskFlow
3. Registering a custom job handler
4. Starting workers
5. Creating a job
6. Shutting down gracefully

package main

import (
    "context"
    "database/sql"
    "fmt"
    "time"

    _ "github.com/go-sql-driver/mysql"
    "github.com/sky93/taskflow"
)

// MyPayload is the shape of the data we expect in the job payload.
type MyPayload struct {
    Greeting string
}

// HelloHandler processes jobs of type "HELLO".
func HelloHandler(jr taskflow.JobRecord) (any, error) {
    var payload MyPayload
    if err := jr.GetPayload(&payload); err != nil {
        return nil, err
    }

    // Here we just print the greeting; real logic can be anything.
    fmt.Println("Received greeting:", payload.Greeting)
    return nil, nil
}

func main() {
    ctx := context.Background()

    // 1) Connect to the DB
    dsn := "root:password@tcp(127.0.0.1:3306)/myDbName?parseTime=true"
    db, err := sql.Open("mysql", dsn)
    if err != nil {
        panic(err)
    }
    if err := db.Ping(); err != nil {
        panic(err)
    }
    fmt.Println("Connected to database.")

    // 2) Create the taskflow config
    cfg := taskflow.Config{
        DB:           db,
        RetryCount:   3,
        BackoffTime:  30 * time.Second,
        PollInterval: 5 * time.Second,
        JobTimeout:   10 * time.Second,

        // Optional logging
        InfoLog: func(ev taskflow.LogEvent) {
            fmt.Printf("[INFO] %s\n", ev.Message)
        },
        ErrorLog: func(ev taskflow.LogEvent) {
            fmt.Printf("[ERROR] %s\n", ev.Message)
        },
    }

    // 3) Create an instance of TaskFlow
    flow := taskflow.New(cfg)

    // 4) Register our "HELLO" handler
    flow.RegisterHandler("HELLO", HelloHandler)

    // 5) Start workers (2 concurrent workers)
    flow.StartWorkers(ctx, 2)

    // Create a new "HELLO" job
    jobID, err := flow.CreateJob(ctx, "HELLO", MyPayload{Greeting: "Hello from TaskFlow!"}, time.Now())
    if err != nil {
        panic(err)
    }
    fmt.Printf("Created job ID %d\n", jobID)

    // Let it run for a few seconds
    time.Sleep(5 * time.Second)

    // 6) Shutdown gracefully
    flow.Shutdown(10 * time.Second)
    fmt.Println("All done.")
}

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Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository
2. Create a new branch for your feature or fix
3. Commit your changes, and add tests if possible
4. Submit a pull request and provide a clear description of your changes

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License

This project is licensed under the MIT License.