Air: Live reload on Golang applications

Go is a programming language with advanced features and clean syntax. It has a robust and well-documented common library, and has focus on good software engineering and principles.

Although Go is a great language, there's one downside: it needs to be recompiled every time after a single line change.

So, to make our lives easier in this post we're gonna learn how to use Air as our live reload.

---

App

Init with Go mod

go mod init helloworld

Creating App Go file

package main

import (
    "fmt"
    "net/http"
)

func main() {
    port := 3000
    fmt.Println("Starting Server on port", port)

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        w.Write([]byte("Hello, World"))
    })
    http.ListenAndServe(":3000", nil)
}

Air:

Installing Air.

go get -u github.com/cosmtrek/air

Air configuration file

air init

Starting Air.

air

You'll have the following result:

Now after any file change Air will reload your app automatically.

---

Air and Docker

First we need to create a Dockerfile

# Dockerfile

FROM cosmtrek/air

RUN mkdir -p /app/dist
COPY ./ /app/
WORKDIR /app/

RUN go get -d -v ./...
RUN go install -v ./...

CMD ["air"]

Now we need to create a docker-compose to make our life easier

# docker-compose.yml

version: '3.7'
services:
  app:
    build: .
    ports:
      - '3000:3000'
    volumes:
      - ./:/app/

Now you just need to run docker-compose up

And you'll have the following result:

References:

• Air: https://github.com/cosmtrek/air
• Golang-book: https://www.golang-book.com/books/intro/1

Comments

[Possawat Sanorkam]

Thank you for your post. Could you please give me the dockerfile recipe without using the image from cosmtrek/air?

Great!

[Breno Alves]

# binary will be $(go env GOPATH)/bin/air
curl -sSfL https://raw.githubusercontent.com/cosmtrek/air/master/install.sh | sh -s -- -b $(go env GOPATH)/bin

# or install it into ./bin/
curl -sSfL https://raw.githubusercontent.com/cosmtrek/air/master/install.sh | sh -s

air -v

you can find this script on air github README. Just use it to install within your docker container and I believe you're good to go :)

[Newton Neto]

Me ajudou demais, estou aprendendo Go e recompilar o código a cada alteração se prova algo muito irritante.

[Lucas Santos]

Brabo demais!!!