Echo で HTTP リクエストヘッダをミドルウェアでダンプする ref: https://qiita.com/shin1x1/items/cfe7568cecbaffe0b23c

file0.go

package main

import (
    "github.com/labstack/echo"
    "fmt"
    "log"
    "os"
)

func main() {
    e := echo.New()
    e.Use(func(next echo.HandlerFunc) echo.HandlerFunc {
        return func(c echo.Context) error {
            if err := next(c); err != nil {
                c.Error(err)
            }

            output := fmt.Sprintf("%#v", c.Request().Header)

            os.Stdout.Write([]byte(output + "\n"))
            return next(c)
        }
    })

    log.Fatal(e.Start(":9001"))
}

file1.txt

http.Header{"Cache-Control":[]string{"max-age=0"}, "User-Agent":[]string{"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"}, "Accept":[]string{"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8"}, "Accept-Encoding":[]string{"gzip, deflate, br"}, "Accept-Language":[]string{"ja,en-US;q=0.9,en;q=0.8"}, "Connection":[]string{"keep-alive"}, "Upgrade-Insecure-Requests":[]string{"1"}}