machinery-plugins/examples/etcd/main.go

package main

import (
	"context"
	"errors"
	"fmt"
	"os"
	"time"

	"github.com/RichardKnop/machinery/v2"
	redisbackend "github.com/RichardKnop/machinery/v2/backends/redis"
	"github.com/RichardKnop/machinery/v2/config"
	"github.com/RichardKnop/machinery/v2/example/tracers"
	"github.com/RichardKnop/machinery/v2/log"
	"github.com/RichardKnop/machinery/v2/tasks"
	"github.com/google/uuid"
	"github.com/opentracing/opentracing-go"
	opentracinglog "github.com/opentracing/opentracing-go/log"
	"github.com/urfave/cli"

	etcdbroker "github.com/ifooth/machinery-plugins/brokers/etcd"
	exampletasks "github.com/ifooth/machinery-plugins/examples/tasks"
	etcdlock "github.com/ifooth/machinery-plugins/locks/etcd"
)

var (
	app *cli.App
)

func init() {
	// Initialise a CLI app
	app = cli.NewApp()
	app.Name = "machinery"
	app.Usage = "machinery worker and send example tasks with machinery send"
	app.Version = "0.0.0"
}

func main() {
	// Set the CLI app commands
	app.Commands = []cli.Command{
		{
			Name:  "worker",
			Usage: "launch machinery worker",
			Action: func(c *cli.Context) error {
				if err := worker(); err != nil && !errors.Is(err, machinery.ErrWorkerQuitGracefully) {
					return cli.NewExitError(err.Error(), 1)
				}
				return nil
			},
		},
		{
			Name:  "send",
			Usage: "send example tasks ",
			Action: func(c *cli.Context) error {
				if err := send(); err != nil {
					return cli.NewExitError(err.Error(), 1)
				}
				return nil
			},
		},
	}

	// Run the CLI app
	_ = app.Run(os.Args)
}

func startServer() (*machinery.Server, error) {
	cnf := &config.Config{
		DefaultQueue:    "machinery_tasks",
		Broker:          "redis://localhost:6379",
		ResultBackend:   "redis://localhost:6379",
		ResultsExpireIn: 3600,
	}

	// Create server instance
	// broker := redisbroker.NewGR(cnf, []string{"localhost:6379"}, 1)
	broker, err := etcdbroker.New(cnf, "http://127.0.0.1:2379")
	if err != nil {
		return nil, err
	}

	// lock := redislock.New(cnf, []string{"localhost:6379"}, 3, 2)
	lock, err := etcdlock.New(cnf, "http://127.0.0.1:2379", 3)
	if err != nil {
		return nil, err
	}
	backend := redisbackend.NewGR(cnf, []string{"localhost:6379"}, 3)
	server := machinery.NewServer(cnf, broker, backend, lock)

	// Register tasks
	tasksMap := map[string]interface{}{
		"add":               exampletasks.Add,
		"multiply":          exampletasks.Multiply,
		"sum_ints":          exampletasks.SumInts,
		"sum_floats":        exampletasks.SumFloats,
		"concat":            exampletasks.Concat,
		"split":             exampletasks.Split,
		"panic_task":        exampletasks.PanicTask,
		"long_running_task": exampletasks.LongRunningTask,
	}

	return server, server.RegisterTasks(tasksMap)
}

func worker() error {
	consumerTag := "machinery_worker"

	cleanup, err := tracers.SetupTracer(consumerTag)
	if err != nil {
		log.FATAL.Fatalln("Unable to instantiate a tracer:", err)
	}
	defer cleanup()

	server, err := startServer()
	if err != nil {
		return err
	}

	// The second argument is a consumer tag
	// Ideally, each worker should have a unique tag (worker1, worker2 etc)
	worker := server.NewWorker(consumerTag, 0)

	// Here we inject some custom code for error handling,
	// start and end of task hooks, useful for metrics for example.
	errorHandler := func(err error) {
		log.ERROR.Println("I am an error handler:", err)
	}

	preTaskHandler := func(signature *tasks.Signature) {
		log.INFO.Println("I am a start of task handler for:", signature.Name)
	}

	postTaskHandler := func(signature *tasks.Signature) {
		log.INFO.Println("I am an end of task handler for:", signature.Name)
	}

	worker.SetPostTaskHandler(postTaskHandler)
	worker.SetErrorHandler(errorHandler)
	worker.SetPreTaskHandler(preTaskHandler)

	return worker.Launch()
}

func send() error {
	cleanup, err := tracers.SetupTracer("sender")
	if err != nil {
		log.FATAL.Fatalln("Unable to instantiate a tracer:", err)
	}
	defer cleanup()

	server, err := startServer()
	if err != nil {
		return err
	}

	var (
		addTask0 tasks.Signature
	)

	var initTasks = func() {
		addTask0 = tasks.Signature{
			Name: "add",
			Args: []tasks.Arg{
				{
					Type:  "int64",
					Value: 1,
				},
				{
					Type:  "int64",
					Value: 1,
				},
			},
		}

	}

	/*
	 * Lets start a span representing this run of the `send` command and
	 * set a batch id as baggage so it can travel all the way into
	 * the worker functions.
	 */
	span, ctx := opentracing.StartSpanFromContext(context.Background(), "send")
	defer span.Finish()

	batchID := uuid.New().String()
	span.SetBaggageItem("batch.id", batchID)
	span.LogFields(opentracinglog.String("batch.id", batchID))

	log.INFO.Println("Starting batch:", batchID)

	/*
	 * First, let's try sending a single task
	 */
	initTasks()

	now := time.Now().Add(time.Second * 10)
	addTask0.ETA = &now
	asyncResult, err := server.SendTaskWithContext(ctx, &addTask0)
	if err != nil {
		return fmt.Errorf("Could not send task: %s", err.Error())
	}

	log.INFO.Println("Single task:", asyncResult.Signature.UUID)

	if err := server.RegisterPeriodicTask("* * * * *", "hello", &addTask0); err != nil {
		return err
	}

	time.Sleep(time.Second * 120000)

	return nil
}