timeout.md

id
timeout

Timeout

There exist two distinct implementations of timeout middleware Fiber.

New

Wraps a fiber.Handler with a timeout. If the handler takes longer than the given duration to return, the timeout error is set and forwarded to the centralized ErrorHandler.

:::caution This has been deprecated since it raises race conditions. :::

NewWithContext

As a fiber.Handler wrapper, it creates a context with context.WithTimeout and pass it in UserContext.

If the context passed executions (eg. DB ops, Http calls) takes longer than the given duration to return, the timeout error is set and forwarded to the centralized ErrorHandler.

It does not cancel long running executions. Underlying executions must handle timeout by using context.Context parameter.

Signatures

func New(handler fiber.Handler, timeout time.Duration, timeoutErrors ...error) fiber.Handler
func NewWithContext(handler fiber.Handler, timeout time.Duration, timeoutErrors ...error) fiber.Handler

Examples

Import the middleware package that is part of the Fiber web framework

import (
  "github.com/gofiber/fiber/v2"
  "github.com/gofiber/fiber/v2/middleware/timeout"
)

After you initiate your Fiber app, you can use the following possibilities:

func main() {
	app := fiber.New()

	h := func(c *fiber.Ctx) error {
		sleepTime, _ := time.ParseDuration(c.Params("sleepTime") + "ms")
		if err := sleepWithContext(c.UserContext(), sleepTime); err != nil {
			return fmt.Errorf("%w: execution error", err)
		}
		return nil
	}

	app.Get("/foo/:sleepTime", timeout.New(h, 2*time.Second))
	log.Fatal(app.Listen(":3000"))
}

func sleepWithContext(ctx context.Context, d time.Duration) error {
	timer := time.NewTimer(d)

	select {
	case <-ctx.Done():
		if !timer.Stop() {
			<-timer.C
		}
		return context.DeadlineExceeded
	case <-timer.C:
	}
	return nil
}

Test http 200 with curl:

curl --location -I --request GET 'http://localhost:3000/foo/1000' 

Test http 408 with curl:

curl --location -I --request GET 'http://localhost:3000/foo/3000' 

Use with custom error:

var ErrFooTimeOut = errors.New("foo context canceled")

func main() {
	app := fiber.New()
	h := func(c *fiber.Ctx) error {
		sleepTime, _ := time.ParseDuration(c.Params("sleepTime") + "ms")
		if err := sleepWithContextWithCustomError(c.UserContext(), sleepTime); err != nil {
			return fmt.Errorf("%w: execution error", err)
		}
		return nil
	}

	app.Get("/foo/:sleepTime", timeout.NewWithContext(h, 2*time.Second, ErrFooTimeOut))
	log.Fatal(app.Listen(":3000"))
}

func sleepWithContextWithCustomError(ctx context.Context, d time.Duration) error {
	timer := time.NewTimer(d)
	select {
	case <-ctx.Done():
		if !timer.Stop() {
			<-timer.C
		}
		return ErrFooTimeOut
	case <-timer.C:
	}
	return nil
}

Sample usage with a DB call:

func main() {
	app := fiber.New()
	db, _ := gorm.Open(postgres.Open("postgres://localhost/foodb"), &gorm.Config{})

	handler := func(ctx *fiber.Ctx) error {
		tran := db.WithContext(ctx.UserContext()).Begin()
		
		if tran = tran.Exec("SELECT pg_sleep(50)"); tran.Error != nil {
			return tran.Error
		}
		
		if tran = tran.Commit(); tran.Error != nil {
			return tran.Error
		}

		return nil
	}

	app.Get("/foo", timeout.NewWithContext(handler, 10*time.Second))
	log.Fatal(app.Listen(":3000"))
}