Docker Desktop 4.18 is an exciting release with a lot of great new features like Docker Scout, Compose Watch, Container File Explorer etc. that will make it easier for developers to work with Docker.
One of the most exciting features introduced is Docker init. This feature generates Docker assets for projects, making it easier to create Docker images and containers. This is a great addition for developers who want to quickly create and manage Docker assets without having to manually configure everything.
Introducing the docker init CLI
Docker init is a CLI command that was introduced in Docker Desktop to simplify the process of initializing a new project to run in a Docker container. When you run the docker init command in your project directory, it will guide you through the creation of the necessary files for your project with sensible defaults. These files include:
- .dockerignore
- Dockerfile
- docker-compose.yaml
The docker init command also allows you to choose the application platform that your project uses and the relative directory of your main package. Additionally, it can generate Docker assets for your project using the Docker Scout CLI and provides an adminless Mac install flow that does not require admin privileges.
Getting Started
Step 1. Initialize the Docker assets
Welcome to the Docker Init CLI!
This utility will walk you through creating the following files with sensible defaults for your project:
- .dockerignore
- Dockerfile
- compose.yaml
Let's get started!
? What application platform does your project use? [Use arrows to move, type to filter]
ASP.NET Core - (detected) suitable for an ASP.NET Core application
> Go - suitable for a Go server application
Python - suitable for a Python server application
Node - suitable for a Node server application
Rust - suitable for a Rust server application
Other - general purpose starting point for containerizing your application
Don't see something you need? Let us know!
Quit
Step 2. Choose your preferred language
For this demo, I will choose Go and 1.20 as Go version.
Before you choose a relation directory in the next step, follow the next step.
Step 3. Creating a simple Go Program
Before you choose relative directory of your main package, let’s open a new terminal and create a simple Go program that exposes a “Hello, World!” app over HTTP.
package main
import (
"fmt"
"net/http"
)
func main() {
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Hello, World!")
})
fmt.Println("Listening on port 8080...")
err := http.ListenAndServe(":8080", nil)
if err != nil {
panic(err)
}
}
This program listens for incoming HTTP requests on port 8080 and responds with the text “Hello, World!” for any incoming request. You can run this program using the go run command and then visit http://localhost:8080 in your web browser to see the output.
go run main.go
The output should show Listening on port 8080…. Then, visit http://localhost:8080 in your web browser to see the “Hello, World!” message.
Ensure that you have the go.sum file with the following content. The go.sum file is created automatically by the Go module system whenever new dependencies are added or removed from a module. When a new dependency is added to a module, the Go module system fetches the dependency and computes its checksum, which is then added to the go.sum file. If the dependency is already present in the go.sum file, the Go module system verifies that its checksum matches the expected value.:
cat go.sum
github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=Step 4. Visualising the Project Directory
This is how the project directory structure look like:
tree
.
├── Dockerfile
├── docker-compose.yaml
├── go.sum
└── main.go
1 directory, 4 files
Go mod is a command-line tool that is built into the Go programming language. It is used to manage dependencies in Go projects. Go mod provides a way to declare and manage dependencies, versioning, and modules, which are collections of related Go packages.The Go mod CLI is the command-line interface for Go mod. It is used to run commands to manage modules, dependencies, and versions in Go projects.
Let’s initializes a new Go module in the current directory.
go mod init helloworld
tree
.
├── Dockerfile
├── docker-compose.yaml
├── go.mod
├── go.sum
└── main.go
1 directory, 5 filesGetting Ready !
Open the original terminal and just press “.” so that it picks up the default directory where our main.go file is located. It will show the following results:
? What's the relative directory (with a leading .) of your main package? .
? What port does your server listen on? 8080
CREATED: .dockerignore
CREATED: Dockerfile
CREATED: docker-compose.yaml
✔ Your Docker files are ready!
Take a moment to review them and tailor them to your application.
When you're ready, start your application by running: docker compose up --build -d
Your application will be available at http://localhost:8080
To stop your application, run: docker compose downStep 5. Building the container
% docker compose up --build -d
Step 6. Listing the services
docker compose ps
NAME IMAGE COMMAND SERVICE CREATED STATUS PORTS
sample_app-server-1 sample_app-server "/bin/server" server 6 seconds ago Up 5 seconds 0.0.0.0:8080->8080/tcp
Step 7. Accessing the App
% curl localhost:8080
Hello from Docker!
