example_job_cancel_test.go

package river_test

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"os"

	"github.com/jackc/pgx/v5/pgxpool"

	"github.com/riverqueue/river"
	"github.com/riverqueue/river/riverdbtest"
	"github.com/riverqueue/river/riverdriver/riverpgxv5"
	"github.com/riverqueue/river/rivershared/riversharedtest"
	"github.com/riverqueue/river/rivershared/util/slogutil"
	"github.com/riverqueue/river/rivershared/util/testutil"
)

type CancellingArgs struct {
	ShouldCancel bool
}

func (args CancellingArgs) Kind() string { return "Cancelling" }

type CancellingWorker struct {
	river.WorkerDefaults[CancellingArgs]
}

func (w *CancellingWorker) Work(ctx context.Context, job *river.Job[CancellingArgs]) error {
	if job.Args.ShouldCancel {
		fmt.Println("cancelling job")
		return river.JobCancel(errors.New("this wrapped error message will be persisted to DB"))
	}
	return nil
}

// Example_jobCancel demonstrates how to permanently cancel a job from within
// Work using JobCancel.
func Example_jobCancel() { //nolint:dupl
	ctx := context.Background()

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

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

	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: 10},
		},
		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)
	}

	// Not strictly needed, but used to help this test wait until job is worked.
	subscribeChan, subscribeCancel := riverClient.Subscribe(river.EventKindJobCancelled)
	defer subscribeCancel()

	if err := riverClient.Start(ctx); err != nil {
		panic(err)
	}
	if _, err = riverClient.Insert(ctx, CancellingArgs{ShouldCancel: true}, 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:
	// cancelling job
}