sqlq

:warning: still very experimental! proceed with care!

sqlq is a SQL-backed, persistent, job queuing solution.

Usage

To start using sqlq add it to your dependencies with:

go get -u github.com/mergestat/sqlq

Enqueing new jobs

Using the sqlq.Enqueue() function, push a job to a queue:

func NewSendMail(args ...string) *sqlq.JobDescription {
    var params = args // somehow serialize args ... using json.Encode() probably
    return sqlq.NewJobDesc("send-email", WithParameters(params));
}

var conn *sql.DB // handle to an open database connection

job, err := sqlq.Enqueue(conn, "default", NewSendMail(from, to, body))
if err != nil {
    // handle error here
}

De-queuing and processing jobs

To de-queue and process a job, you need to use one of the available runtimes. Currently, the only available runtime is the embed runtime available under github.com/mergestat/sqlq/runtime/embed package. The following example demonstrates how to implement a job handler for that runtime.

func SendMail() sqlq.Handlerfunc {
    return func(ctx context.Context, job *sqlq.Job) error { 
        // send mail's implementation
        return nil
    }
}

func main() {
    var upstream *sql.DB // handle to an open database connection
    var worker, _ = embed.NewWorker(upstream, embed.WorkerConfig{
            Queues: []sqlq.Queue{"embed/default"}, // queues to watch
    })

    _ = worker.Register("send-mail", SendMail())

    // starting the worker will start the processing routine in background
    if err := worker.Start(); err != nil {
        // handle error
    }

    // wait here .. probably listening for os.Signal

    // make a clear / graceful exit
    if err := worker.Shutdown(5 * time.Second); err != nil {
        // graceful exit failed / didn't complete
        return nil
    }
}

These basic examples are just to give an idea. Refer to tests to see more varied use cases.

Developing

To start a postgres database in Docker and execute tests against it, run:

docker-compose up

and then:

go test ./... -postgres-url postgres://postgres:password@localhost:5432 -v