golang + Docker

Ref
Environment
Preparation
1. main.go
2. Dockerfile
Build and Execute

Ref

Environment

Use Docker Desktop (for Mac)
Use 1.19.4-bullseye not alpine
Not special go library dependency

Preparation

Create folder and file structure

goapp
|- Dockerfile
|- go.mod
|- main.go

go.mod is by “go mod init command”

main.go

package main

import (
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello World!"))
	})
	err := http.ListenAndServe(":8080", nil)
	if err != nil {
		log.Fatal(err)
	}
}

Simple server code, only res when access “/”.

Port is 8080

Dockerfile

FROM golang:1.19.4-bullseye
WORKDIR /app
COPY go.mod ./

COPY *.go ./

RUN go build -o /go-app
EXPOSE 8080
CMD ["/go-app"]

Image is golan Debian bullseye.

Copy go mod and go files and build on the server. Build go files and start go app.

Build and Execute

Let’s build Dockerfile

docker build --tag first-go-app .

Set name “fitst-go-app”

Check build images

docker image ls

Can see

REPOSITORY TAG IMAGE ID CREATED SIZE
first-go-app latest 421e5e5fc8bb 55 seconds ago 850MB

850MB, … Debian is big.

Let’s run this

docker run --publish 8080:8080 first-go-app