Trying to setup a webserver with gin but i get a error

Getting Help
1

Hello members of the Golang Forum,

I’m making a webserver in go this is my first time coding in go btw but i get this error when i try to run my webserver that i made import cycle not allowed. I don’t know why this happens so help will be appreciated

package main

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

func main() {
  r := gin.Default()
  r.GET("/ping", func(c *gin.Context) {
    c.JSON(http.StatusOK, gin.H{
      "message": "pong",
    })
  })
  r.Run()
}

gitpod /workspace/coding (main) $ go run webserver.go
package command-line-arguments
imports GitHub - gin-gonic/gin: Gin is a HTTP web framework written in Go (Golang). It features a Martini-like API with much better performance -- up to 40 times faster. If you need smashing performance, get yourself some Gin.
imports github.com/gin-gonic/gin: import cycle not allowed
gitpod /workspace/coding (main) $

2

Try first without framework and take it from there:

package main

import (
	"fmt"
	"net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	fmt.Fprint(w, "Hello World")
}

func main() {
	http.HandleFunc("/", handler)
	err := http.ListenAndServe(":8080", nil)
	if err != nil {
		fmt.Println("Error:", err)
	}
}

And may I ask why you need framework? IMHO the built in libraries is good enough…

Live hello!

3

Hi,

  1. did you run go mod init before?
  2. did you added gin with go get github.com/gin-gonic/gin ?
1 Like
4

Did you create a go.mod, with something along the lines of go mod init my-base-package-name?

The following works just fine for me.

$ mkdir test-server

$ cd test-server/

$ go mod init test-server
go: creating new go.mod: module test-server

$ go get github.com/gin-gonic/gin
go: added github.com/bytedance/sonic v1.9.1
go: added github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311
go: added github.com/gabriel-vasile/mimetype v1.4.2
go: added github.com/gin-contrib/sse v0.1.0
go: added github.com/gin-gonic/gin v1.9.1
go: added github.com/go-playground/locales v0.14.1
go: added github.com/go-playground/universal-translator v0.18.1
go: added github.com/go-playground/validator/v10 v10.14.0
go: added github.com/goccy/go-json v0.10.2
go: added github.com/json-iterator/go v1.1.12
go: added github.com/klauspost/cpuid/v2 v2.2.4
go: added github.com/leodido/go-urn v1.2.4
go: added github.com/mattn/go-isatty v0.0.19
go: added github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd
go: added github.com/modern-go/reflect2 v1.0.2
go: added github.com/pelletier/go-toml/v2 v2.0.8
go: added github.com/twitchyliquid64/golang-asm v0.15.1
go: added github.com/ugorji/go/codec v1.2.11
go: added golang.org/x/arch v0.3.0
go: added golang.org/x/crypto v0.9.0
go: added golang.org/x/net v0.10.0
go: added golang.org/x/sys v0.8.0
go: added golang.org/x/text v0.9.0
go: added google.golang.org/protobuf v1.30.0
go: added gopkg.in/yaml.v3 v3.0.1

$ cat << EOF > test-server.go
package main 

import ( 
  "net/http" 

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

func main() { 
  r := gin.Default() 
  r.GET("/ping", func(c *gin.Context) { 
    c.JSON(http.StatusOK, gin.H{ 
      "message": "pong", 
    }) 
  }) 
  r.Run() 
} 
EOF

$ go run test-server.go
5

You have not mentioned the listen port

6

gin defaults to listening on port 8080.

7

Yes. For safer side you assign other port and check…

May be 8080 port is using other applications

8

The problem that the original poster had was with compilation. They’d not got as far as running the built application.

9 
package main

import (
	"github.com/gin-gonic/gin"
	"net/http"
)

func main() {
	r := gin.Default()
	r.GET("/ping", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"message": "pong",
		})
	})
	r.Run()
}

I have tested this code it is working 
net/http add in your code

http://localhost:8080/ping
{
“message”: “pong”
}
in postman