Load Balancing

This recipe demonstrates how to use Nginx as a reverse proxy server to load balance traffic across multiple Echo servers.

Echo

package main

import (
  "context"
  "fmt"
  "net/http"
  "os"

  "github.com/labstack/echo/v5"
  "github.com/labstack/echo/v5/middleware"
)

var index = `
  <!DOCTYPE html>
  <html lang="en">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Upstream Server</title>
    <style>
      h1, p {
        font-weight: 300;
      }
    </style>
  </head>
  <body>
    <p>
      Hello from upstream server %s
    </p>
  </body>
  </html>
`

func main() {
  name := os.Args[1]
  port := os.Args[2]

  e := echo.New()
  e.Use(middleware.Recover())
  e.Use(middleware.RequestLogger())

  e.GET("/", func(c *echo.Context) error {
    return c.HTML(http.StatusOK, fmt.Sprintf(index, name))
  })

  sc := echo.StartConfig{Address: port}
  if err := sc.Start(context.Background(), e); err != nil {
    e.Logger.Error("failed to start server", "error", err)
  }
}

Start servers

cd upstream
go run server.go server1 :8081
go run server.go server2 :8082

Nginx

1) Install Nginx

See the Nginx installation guide.

2) Configure Nginx

Create a file /etc/nginx/sites-enabled/localhost with the following content:

upstream localhost {
  server localhost:8081;
  server localhost:8082;
}

server {
  listen          8080;
  server_name     localhost;
  access_log      /var/log/nginx/localhost.access.log combined;

  location / {
    proxy_pass      http://localhost;
  }
}

3) Restart Nginx

service nginx restart

Browse to https://localhost:8080, and you should see a webpage served from either “server 1” or “server 2”.

Hello from upstream server server1