logger_skipper.go

package main

import (
	"fmt"
	"github.com/labstack/echo/middleware"
	"net/http"

	"github.com/labstack/echo"
)

// Skipper determines which requests to log
func Skipper(c echo.Context) bool {
	res := c.Response()
	status := res.Status
	fmt.Println("Skipper status: ", status)

	// Skips request logging if not success status,
	// those are logged by customHTTPErrorHandler
	if status > 299 {
		return true
	}

	return false
}

func customHTTPErrorHandler(err error, c echo.Context) {
	res := c.Response()
	status := res.Status
	fmt.Println("customHTTPErrorHandler status", status)

	// Parse error
	code := http.StatusInternalServerError
	message := http.StatusText(http.StatusInternalServerError)
	if he, ok := err.(*echo.HTTPError); ok {
		code = he.Code
		message = fmt.Sprintf("%s", he.Message)
	}
	type response struct {
		Message string `json:"message"`
	}
	resp := response{
		Message: message,
	}

	// Respond with error
	if err := c.JSON(code, resp); err != nil {
		c.Logger().Error(err)
	}

	// Log error
	c.Logger().Error(err)
}

func main() {
	// Echo instance
	e := echo.New()

	// Middleware
	loggerConfig := middleware.DefaultLoggerConfig
	loggerConfig.Skipper = Skipper
	loggerConfig.Format = `{"status":${status},"error":"${error}"}`
	e.Use(middleware.LoggerWithConfig(loggerConfig))

	e.HTTPErrorHandler = customHTTPErrorHandler

	// Routes
	e.GET("/", hello)

	// Start server
	e.Logger.Fatal(e.Start(":1323"))
}

// Handler
func hello(c echo.Context) error {
	fmt.Println("hello")
	return echo.NewHTTPError(http.StatusInternalServerError)
}

// This file demonstrates that the logger skipper cannot be used
// to check HTTP status unless it is called after the inner middleware...

// BEFORE
//Skipper status:  200
//hello
//customHTTPErrorHandler status 200
//{"time":"2018-11-29T16:52:14.472436+02:00","level":"ERROR","prefix":"echo","file":"main.go","line":"51","message":"code=500, message=Internal Server Error"}
//{"status":500,"error":"code=500, message=Internal Server Error"}

// AFTER
//hello
//customHTTPErrorHandler status 200
//{"time":"2018-11-29T16:53:12.321411+02:00","level":"ERROR","prefix":"echo","file":"main.go","line":"51","message":"code=500, message=Internal Server Error"}
//Skipper status:  500