GAEでHello World with Gin

$ go get -u github.com/gin-gonic/gin

module goae

go 1.14

require (
	github.com/gin-gonic/gin v1.6.3 // indirect
	github.com/go-playground/validator/v10 v10.3.0 // indirect
	github.com/golang/protobuf v1.4.2 // indirect
	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
	github.com/modern-go/reflect2 v1.0.1 // indirect
	golang.org/x/sys v0.0.0-20200602225109-6fdc65e7d980 // indirect
	google.golang.org/protobuf v1.24.0 // indirect
	gopkg.in/yaml.v2 v2.3.0 // indirect
)

package main

import (
	"log"
	"net/http"
	"os"

	"github.com/gin-gonic/gin"
)

func main() {
	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
		log.Printf("Defaulting to port %s", port)
	}

	r := gin.New()
	r.GET("/", func(c *gin.Context) {
		c.String(http.StatusOK, "Hello World!")
	})
	r.GET("/ping", func(c *gin.Context) {
		c.String(http.StatusOK, "pong")
	})

	log.Printf("Listening on port %s", port)
	r.Run(":" + port)
}

$ go run main.go
2020/06/08 14:16:17 Defaulting to port 8080
[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:   export GIN_MODE=release
 - using code:  gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /                         --> main.main.func1 (1 handlers)
[GIN-debug] GET    /ping                     --> main.main.func2 (1 handlers)
2020/06/08 14:16:17 Listening on port 8080
[GIN-debug] Listening and serving HTTP on :8080

$ curl localhost:8080
Hello World!%
$ curl localhost:8080/ping
pong%

$ gcloud app deploy

$ gcloud app browse