revolver

revolver

Revolver is a simple CLI tool for live reloading your Go applications.
Revolver detects changes in your project files and restarts your application automatically.

Installation

go install github.com/snowmerak/revolver@latest

Usage

revolver <command> <config-file>

Init

revolver init dev.yaml

This command will create a dev.yaml file in the current directory with the following content:

log_level: info
root: .
exec: .
ports:
  - port: 8080
    name: http
    env: PORT
scripts:
  preload: go build -o app .
  run: ./app
  cleanup: rm app
exts:
  - .go

Watch

revolver watch dev.yaml

This command will start watching the files in the current directory and restart the application when a change is detected.

ReverseProxy

Revolver can also act as a tcp reverse proxy for your application.
This is useful when deploying your application with zero downtime.
But revolver is using proxyprotocol v2 to pass the client's IP address to the application.
You must implement the proxyprotocol v2 in your application.

But your application written in Go can use the github.com/snowmerak/revolver/listener package to use the proxyprotocol v2.

go get github.com/snowmerak/revolver

package main

import (
	"github.com/snowmerak/revolver/listener"
)

func main() {
	port := os.Getenv("PORT")
	if port == "" {
        port = "8080"
	}
	
    ln, err := listener.New("0.0.0.0:" + port)
	if err != nil {
        log.Fatal(err)
    }
	
	...
}

Example

If you have a project structure like this:

.
├── cmd
│   └── server
│       └── main.go
└── go.mod

You must edit the dev.yaml file to match your project structure:

log_level: info
root: .
exec: ./cmd/server
ports:
  - port: 8080
    name: http
    env: PORT
scripts:
  preload: go build -o app .
  run: ./app
  cleanup: rm app
exts:
  - .go
  - .mod
  - .sum

Then you can run the following command:

revolver watch dev.yaml

Dockerfile

You can also use revolver in a Dockerfile:

FROM docker.io/golang:latest

RUN go install github.com/snowmerak/revolver@latest

WORKDIR /app

COPY . .
# or MOUNT your project files

CMD ["revolver", "watch", "dev.yaml"]

version: '3.8'
service:
    app:
        build:
            context:
            dockerfile: dev.Dockerfile
        ports:
        - 8080:8080
        volumes:
        - .:/app