Timeout middleware

[jeyldii]

Hi! I want to create timeout middleware

Checklist

• Dependencies installed
• No typos
• Searched existing issues and docs

Expected behaviour

middleware.Timeout()

Actual behaviour

middleware package do not produce timeout middleware

Working code to debug

I try something like this, yes i know it's wrong way:)

func timeout(next echo.HandlerFunc) echo.HandlerFunc {
	return func(c echo.Context) error {
		ctx, _ := context.WithTimeout(context.Background(), time.Second*2)

		go func() {
			select {
			case <-ctx.Done():
				_ = c.JSON(http.StatusGatewayTimeout, ctx.Err())
			}
		}()

		c.SetRequest(c.Request().WithContext(ctx))
		return next(c)
	}
}

Version/commit

latest

[jeyldii]

I migrate my app from gin to echo, because gin has timeout middleware, but it panics.

[pafuent]

Hi, I hope this example helps you on your Timeout middleware journey

package main

import (
	"context"
	"net/http"
	"time"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"github.com/labstack/gommon/log"
)

func main() {
	// Echo instance
	e := echo.New()
	e.Logger.SetLevel(log.INFO)

	// Middleware
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	// Route
	e.GET("/sleep", func(c echo.Context) (err error) {
		// This select make the trick of finish this request when the middleware timeouts
		select {
		case <-time.After(5 * time.Second):
			c.Logger().Info("Done")
			return c.JSON(http.StatusOK, "Done")
		case <-c.Request().Context().Done():
			c.Logger().Info("Timeout")
			return nil
		}
	}, timeoutMiddleware)

	// Start server
	e.Logger.Fatal(e.Start(":8080"))
}

func timeoutMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
	return func(c echo.Context) error {
		// Just to play easily with the middleware using a query parameter
		timeout := 2 * time.Second
		if t, err := time.ParseDuration(c.QueryParam("timeout")); err == nil {
			timeout = t
		}

		// This is the context that controls the timeout. Its parent is the original
		// http.Request context
		ctx, cancel := context.WithTimeout(c.Request().Context(), timeout)
		defer cancel() // releases resources if next(c) completes before timeout elapses

		// A channel and a goroutine to run next(c) and know if its ends
		done := make(chan error, 1)
		go func() {
			// This goroutine will not stop even this middleware timeouts,
			// unless someone in the next(c) call chain handle ctx.Done() properly
			c.SetRequest(c.Request().Clone(ctx))
			done <- next(c)
		}()

		// The real timeout logic
		select {
		case <-ctx.Done():
			return c.JSON(http.StatusGatewayTimeout, ctx.Err())
		case err := <-done:
			return err
		}
	}
}

Here are some curl that you can use to play with the example

# Timeout
curl -i --request GET --url 'http://127.0.0.1:8080/sleep'
# No timeout
curl -i --request GET --url 'http://127.0.0.1:8080/sleep?timeout=6s'

Please, when you have your Timeout middleware woking don't forget to submit a PR whit it 😉

[pafuent]

Hi @jeyldii, Was my comment helpfull?

[jeyldii]

Hi @jeyldii, Was my comment helpfull?

Hey! Thank you for your answer! I make something like this:

func Timeout(timeout time.Duration) func(next echo.HandlerFunc) echo.HandlerFunc {
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c echo.Context) error {
			ctx, cancel := context.WithTimeout(context.Background(), timeout)
			go func() {
				<-ctx.Done()
				cancel()
			}()
			c.SetRequest(c.Request().WithContext(ctx))
			return next(c)
		}
	}
}

And i manage context.Deadline in my handlers. I think your decision better. I think i can make a PR with middleware soon. Sorry, for late answer :)