Hot Reload in Golang Using Air - 07/04/2024

Hot reload in golang app while development using Air

Hot Reload in Golang Using Air

Prerequisites :

Golang version 1.22 or higher
I tested it on wsl2 in both windows and linux environment

Hot reload without docker container

Create a golang gin application

Create a project directory and install gin-gonic :

go get -u github.com/gin-gonic/gin

Now install Air :

go get -u github.com/cosmtrek/air

Create a simple Gin application

// main.go
package main

import (
"github.com/gin-gonic/gin"
)

func main() {
// Create a new Gin router
router := gin.Default()

// Define a route
router.GET("/", func(c *gin.Context) {
c.JSON(200, gin.H{
    "message": "Hello, Gin!",
})
})

// Run the server on port 8080
router.Run(":8080")
}

initialize the .air.toml configuration file by running this command
```
air init
```
After this, you can just run the air command without additional arguments and it will use the .air.toml file for configuration.
```
air
```

Hot reload in docker container

We are going to use the above application. Create a Dockerfile with following content :

FROM golang:1.22-alpine

WORKDIR /app

RUN go install github.com/cosmtrek/air@latest

COPY go.mod go.sum ./
RUN go mod download

CMD ["air", "-c", ".air.toml"]

Now create a docker-compose.yaml file :

version: "3.8"
services:
web:
    build:
    context: .
    # Correct the path to your Dockerfile
    dockerfile: Dockerfile
    ports:
    - 8080:8080
    # Important to bind/mount your codebase dir to /app dir for live reload
    volumes:
    - ./:/app

Now run docker-compose up and check localhost:8080 in browser.
If your live reload is not working, try poll = true in .air.toml file and rebuild the docker image.