asynq/doc.go

// Copyright 2020 Kentaro Hibino. All rights reserved.
// Use of this source code is governed by a MIT license
// that can be found in the LICENSE file.

/*
Package asynq provides a framework for Redis based distrubted task queue.

Asynq uses Redis as a message broker. To connect to redis,
specify the connection using one of RedisConnOpt types.

	redisConnOpt = asynq.RedisClientOpt{
	    Addr:     "127.0.0.1:6379",
	    Password: "xxxxx",
	    DB:       2,
	}

The Client is used to enqueue a task.

	client := asynq.NewClient(redisConnOpt)

	// Task is created with two parameters: its type and payload.
	// Payload data is simply an array of bytes. It can be encoded in JSON, Protocol Buffer, Gob, etc.
	b, err := json.Marshal(ExamplePayload{UserID: 42})
	if err != nil {
	    log.Fatal(err)
	}

	task := asynq.NewTask("example", b)

	// Enqueue the task to be processed immediately.
	info, err := client.Enqueue(task)

	// Schedule the task to be processed after one minute.
	info, err = client.Enqueue(t, asynq.ProcessIn(1*time.Minute))

The Server is used to run the task processing workers with a given
handler.

	srv := asynq.NewServer(redisConnOpt, asynq.Config{
	    Concurrency: 10,
	})

	if err := srv.Run(handler); err != nil {
	    log.Fatal(err)
	}

Handler is an interface type with a method which
takes a task and returns an error. Handler should return nil if
the processing is successful, otherwise return a non-nil error.
If handler panics or returns a non-nil error, the task will be retried in the future.

Example of a type that implements the Handler interface.

	type TaskHandler struct {
	    // ...
	}

	func (h *TaskHandler) ProcessTask(ctx context.Context, task *asynq.Task) error {
	    switch task.Type {
	    case "example":
	        var data ExamplePayload
	        if err := json.Unmarshal(task.Payload(), &data); err != nil {
	            return err
	        }
	        // perform task with the data

	    default:
	        return fmt.Errorf("unexpected task type %q", task.Type)
	    }
	    return nil
	}
*/
package asynq