example_insert_and_work_test.go

package river_test

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

	"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 SortArgs struct {
	// Strings is a slice of strings to sort.
	Strings []string `json:"strings"`
}

func (SortArgs) Kind() string { return "sort" }

type SortWorker struct {
	river.WorkerDefaults[SortArgs]
}

func (w *SortWorker) Work(ctx context.Context, job *river.Job[SortArgs]) error {
	sort.Strings(job.Args.Strings)
	fmt.Printf("Sorted strings: %+v\n", job.Args.Strings)
	return nil
}

// Example_insertAndWork demonstrates how to register job workers, start a
// client, and insert a job on it to be worked.
func Example_insertAndWork() {
	ctx := context.Background()

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

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

	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)
	}

	// Start a transaction to insert a job. It's also possible to insert a job
	// outside a transaction, but this usage is recommended to ensure that all
	// data a job needs to run is available by the time it starts. Because of
	// snapshot visibility guarantees across transactions, the job will not be
	// worked until the transaction has committed.
	tx, err := dbPool.Begin(ctx)
	if err != nil {
		panic(err)
	}
	defer tx.Rollback(ctx)

	_, err = riverClient.InsertTx(ctx, tx, SortArgs{
		Strings: []string{
			"whale", "tiger", "bear",
		},
	}, nil)
	if err != nil {
		panic(err)
	}

	if err := tx.Commit(ctx); 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:
	// Sorted strings: [bear tiger whale]
}