Golang introduces the implementation method of the corresponding configuration file according to the parameters

1) config Catalog establish dev.env and prod.env

env File example
dev.env

#gin
GIN_DEBUG=true
GIN_PORT=9000

prod.env

#gin
GIN_DEBUG=false
GIN_PORT=9527

2) Use godotenv Import the corresponding file

Without this package, you need to introduce

go get github.com/joho/godotenv

package main

import (
	"flag"
	"log"
	"os"
	
	"github.com/gin-gonic/gin"
	"github.com/joho/godotenv"
)

var envArgs string

func init() {
    
	//  The default is dev Environmental Science 
	flag.StringVar(&envArgs, "env", "dev", " Running environment ")
}

func main() {
    
	//  It can only be used after parsing 
	flag.Parse()
	err := godotenv.Load("./config/" + string(envArgs) + ".env")
	if err != nil {
    
		log.Fatal("Error loading .env file")
	}
	ginPort := os.GetEnv("GIN_PORT")
	debugFlag := os.GetEnv("GIN_DEBUG")
	if debugFlag == "true" {
    
		gin.SetMode(gin.DebugMode)
	} else {
    
		gin.SetMode(gin.ReleaseMode)
	}
	r := gin.Default()
	r.Run(":" + ginPort)
}

Command line execution

#prod Environmental Science 
go run main.go -env=prod
#dev Environmental Science   If env The default value is dev
go run main.go -env=dev