Redis

This is the basic initialization of this backend:

import (
	"log"

	"github.com/pulchre/wingman/backend/redis"
)

func main() {
	backend, err := redis.Init(redis.Options{})
	if err != nil {
		log.Fatal(err)
	}
}

This is required both for the application and for the manager.

The options available are:

• A go-redis options struct.
• BlockingTimeout time.Duration - Timeout for blocking commands to Redis.

Internals

Here is an overview of the stages that a job goes through in the Redis backend.

1. PushJob: RPUSH onto the queue.
2. PopJob: BLPOP pops the next job off the queue. If no job is on the queue, it blocks until the either a job is pushed, the timeout is reached, or the context is cancelled.
3. LockJob: If the job has no LockKey or concurrency is less than 1, we return wingman.LockNotRequired (0). A job may have n concurrency. The locks are a Redis key (wingman:lock:LOCK_KEY:LOCK-ID). We randomly try a lock until we exhaust all the locks or get one. If we cannot get a lock, we move it to the held queue (wingman:held:QUEUE).
4. ProcessJob: SET set the processing key to the job. (wingman:processing:JOB-ID)
5. ReleaseJob: DEL the lock key and LMOVE a job from the held queue to the front of the queue.
6. ClearJob: DEL the processing key
7. FailJob: DEL & SET. first it deletes the processing key, then sets a failed key to the job (wingman:failed:JOB-ID).