Function ExampleNewMiddleware

riverlog/example_new_middleware_test.go:37–100

ExampleNewMiddleware demonstrates the use of riverlog middleware to inject a logger into context that'll persist its output onto the job record.

()

// ExampleNewMiddleware demonstrates the use of riverlog middleware to inject a
// logger into context that'll persist its output onto the job record.
func ExampleNewMiddleware() {
	ctx := context.Background()

	dbPool, err := pgxpool.New(ctx, riversharedtest.TestDatabaseURL())
	if err != nil {
		panic(err)
	}
	defer dbPool.Close()

	workers := river.NewWorkers()
	river.AddWorker(workers, &LoggingWorker{})

	riverClient, err := river.NewClient(riverpgxv5.New(dbPool), initTestConfig(ctx, dbPool, &river.Config{
		Queues: map[string]river.QueueConfig{
			river.QueueDefault: {MaxWorkers: 100},
		},
		Middleware: []rivertype.Middleware{
			riverlog.NewMiddleware(func(w io.Writer) slog.Handler {
				// We have to use a specialized ReplacedAttr without level or
				// timestamps to make test output reproducible, but in reality
				// this would as simple as something like:
				//
				// 	return slog.NewJSONHandler(w, nil)
				return slog.NewTextHandler(w, &slog.HandlerOptions{ReplaceAttr: slogutil.NoLevelTime})
			}, nil),
		},
		Workers: workers,
	}))
	if err != nil {
		panic(err)
	}

	// Out of example scope, but used to wait until a job is worked.
	subscribeChan, subscribeCancel := riverClient.Subscribe(river.EventKindJobCompleted)
	defer subscribeCancel()

	if err := riverClient.Start(ctx); err != nil {
		panic(err)
	}

	_, err = riverClient.Insert(ctx, LoggingArgs{}, nil)
	if err != nil {
		panic(err)
	}

	// Wait for job to complete, extract log data out of metadata, and print it.
	for _, event := range riversharedtest.WaitOrTimeoutN(testutil.PanicTB(), subscribeChan, 1) {
		var metadataWithLog metadataWithLog
		if err := json.Unmarshal(event.Job.Metadata, &metadataWithLog); err != nil {
			panic(err)
		}
		for _, logAttempt := range metadataWithLog.RiverLog {
			fmt.Print(logAttempt.Log)
		}
	}

	if err := riverClient.Stop(ctx); err != nil {
		panic(err)