Dockerize Golang Web Server

In this article we will be looking into how to dockerize a simple Golang web server. We will create a simple web server that returns a JSON response which we will then dockerize, generate docker image and run the container.

First we will create a simple golang web server that returns a JSON response.

package main

import (
  "encoding/json"
  "net/http"
)

type Response struct {
  Message string `json:"message"`
}

func handler(w http.ResponseWriter, r *http.Request) {
  response := Response{Message: "Hello World"}
  w.Header().Set("Content-Type", "application/json")
  json.NewEncoder(w).Encode(response)
}

func main() {
  http.HandleFunc("/", handler)
  http.ListenAndServe(":8080", nil)
}

The above code is a simple golang web server that listens on port 8080 and returns a JSON response with the message Hello World.

Next we will create a Dockerfile that will be used to build a docker image for our web server.

// Use golang:1.23 as base image
FROM golang:1.23


// Create and set the working directory
WORKDIR /app

// Copy the go.mod and go.sum files
COPY go.mod go.sum ./

// Download all dependencies
RUN go mod download

// Copy the source code
COPY . .

// Build the application and name the output binary as main
RUN go build -o main .

// Expose port 8080
EXPOSE 8080

// Run the application
CMD ["./main"]

The above Dockerfile builds a docker image for our simple web server.

To build the docker image, run the following command in the terminal:

docker build -t golang-web-server .

The above command builds a docker image with the tag golang-web-server.

Finally, to run the docker container, run the following command in the terminal:

docker run -p 8080:8080 golang-web-server

This command runs the docker image we built and maps the port 8080 of the host machine(your computer or server) to the port 8080 of the container.

You can now access the web server by visiting http://localhost:8080 in your browser.

In our next article we will look into how we can store the docker image in a docker registry(GitHub Container Registry).