Docker: Go server does not respond - docker

Question

I was learning how to dockerize Go Apps. I created a simple REST API
package main
import "github.com/gin-gonic/gin"
func main() {
server := gin.Default()
server.GET("/", func(ctx *gin.Context) {
ctx.JSON(200, "HELLO SERVER")
})
server.Run("127.0.0.1:3000")
}
and here is the Dockerfile
FROM golang:1.18.3-alpine3.16
RUN mkdir /app
COPY . /app
WORKDIR /app
RUN go mod download
RUN go build -o main .
EXPOSE 3000
CMD "/app/main"
Thing is, when build and run the container, it appears the app starts normally as usual
[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.
[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 (3 handlers)
[GIN-debug] [WARNING] You trusted all proxies, this is NOT safe. We recommend you to set a value.
Please check https://pkg.go.dev/github.com/gin-gonic/gin#readme-don-t-trust-all-proxies for details.
[GIN-debug] Listening and serving HTTP on 127.0.0.1:3000
But here is the issue, when I use Postman and make a get request to 127.0.0.1:3000/, it shows it could not get any response (i.e, the response it gets when there is no such server to connect)
When I run the app using 'go run main.go' it works fine.
It would be really great if you could help me out with this

Answer 1

maybe you should listen on 0.0.0.0:3000
func main() {
server := gin.Default()
server.GET("/", func(ctx *gin.Context) {
ctx.JSON(200, "HELLO SERVER")
})
// server.Run("127.0.0.1:3000")
server.Run("0.0.0.0:3000")
}