reverse-proxy
Reverse Proxy
原文：https://echo.labstack.com/docs/cookbook/reverse-proxy
This recipe demonstrates how you can use Echo as a reverse proxy server and load balancer in front of your favorite applications like WordPress, Node.js, Java, Python, Ruby or even Go. For simplicity, I will use Go upstream servers with WebSocket.
1) Identify upstream target URL(s)
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| url1, err := url.Parse("http://localhost:8081")
if err != nil {
e.Logger.Fatal(err)
}
url2, err := url.Parse("http://localhost:8082")
if err != nil {
e.Logger.Fatal(err)
}
targets := []*middleware.ProxyTarget{
{
URL: url1,
},
{
URL: url2,
},
}
|
2) Setup proxy middleware with upstream targets
In the following code snippet we are using round-robin load balancing technique. You may also use middleware.NewRandomBalancer().
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| e.Use(middleware.Proxy(middleware.NewRoundRobinBalancer(targets)))
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To setup proxy for a sub-route use Echo#Group().
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| g := e.Group("/blog")
g.Use(middleware.Proxy(...))
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3) Start upstream servers
cd upstreamgo run server.go server1 :8081go run server.go server2 :8082
4) Start the proxy server
Browse to http://localhost:1323, and you should see a webpage with an HTTP request being served from “server 1” and a WebSocket request being served from “server 2.”
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| HTTP
Hello from upstream server server1
WebSocket
Hello from upstream server server2!
Hello from upstream server server2!
Hello from upstream server server2!
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Source Code
cookbook/reverse-proxy/upstream/server.go
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| package main
import (
"fmt"
"net/http"
"os"
"time"
"github.com/labstack/echo/v4"
"github.com/labstack/echo/v4/middleware"
"golang.org/x/net/websocket"
)
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>
<h1>HTTP</h1>
<p>
Hello from upstream server %s
</p>
<h1>WebSocket</h1>
<p id="output"></p>
<script>
var ws = new WebSocket('ws://localhost:1323/ws')
ws.onmessage = function(evt) {
var out = document.getElementById('output');
out.innerHTML += evt.data + '<br>';
}
</script>
</body>
</html>
`
func main() {
name := os.Args[1]
port := os.Args[2]
e := echo.New()
e.Use(middleware.Recover())
e.Use(middleware.Logger())
e.GET("/", func(c echo.Context) error {
return c.HTML(http.StatusOK, fmt.Sprintf(index, name))
})
// WebSocket handler
e.GET("/ws", func(c echo.Context) error {
websocket.Handler(func(ws *websocket.Conn) {
defer ws.Close()
for {
// Write
err := websocket.Message.Send(ws, fmt.Sprintf("Hello from upstream server %s!", name))
if err != nil {
e.Logger.Error(err)
}
time.Sleep(1 * time.Second)
}
}).ServeHTTP(c.Response(), c.Request())
return nil
})
e.Logger.Fatal(e.Start(port))
}
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cookbook/reverse-proxy/server.go
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| package main
import (
"net/url"
"github.com/labstack/echo/v4"
"github.com/labstack/echo/v4/middleware"
)
func main() {
e := echo.New()
e.Use(middleware.Recover())
e.Use(middleware.Logger())
// Setup proxy
url1, err := url.Parse("http://localhost:8081")
if err != nil {
e.Logger.Fatal(err)
}
url2, err := url.Parse("http://localhost:8082")
if err != nil {
e.Logger.Fatal(err)
}
targets := []*middleware.ProxyTarget{
{
URL: url1,
},
{
URL: url2,
},
}
e.Use(middleware.Proxy(middleware.NewRoundRobinBalancer(targets)))
e.Logger.Fatal(e.Start(":1323"))
}
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