Function Example_resumableCursor

example_resumable_cursor_job_test.go:55–105

Example_resumableCursor demonstrates the use of a resumable cursor step, a step that can store arbitrary JSON state to resume a partially completed loop.

()

// Example_resumableCursor demonstrates the use of a resumable cursor step, a
// step that can store arbitrary JSON state to resume a partially completed loop.
func Example_resumableCursor() {
	ctx := context.Background()

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

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

	riverClient, err := river.NewClient(riverpgxv5.New(dbPool), &river.Config{
		Logger: slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelWarn, ReplaceAttr: slogutil.NoLevelTime})),
		Queues: map[string]river.QueueConfig{
			river.QueueDefault: {MaxWorkers: 100},
		},
		Schema:   riverdbtest.TestSchema(ctx, testutil.PanicTB(), riverpgxv5.New(dbPool), nil), // only necessary for the example test
		TestOnly: true,                                                                         // suitable only for use in tests; remove for live environments
		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)
	}

	if _, err = riverClient.Insert(ctx, ResumableCursorArgs{
		IDs: []int{1, 2, 3},
	}, nil); err != nil {
		panic(err)
	}

	// Wait for jobs to complete. Only needed for purposes of the example test.
	riversharedtest.WaitOrTimeoutN(testutil.PanicTB(), subscribeChan, 1)

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

	// Output:
	// Processed 1
	// Processed 2
	// Processed 3
}