gitpod/components/gitpod-cli/cmd/forward-port.go
Manuel Alejandro de Brito Fontes bd3ba7cdec Refactor port parsing
2021-06-16 10:45:31 -04:00

78 lines
2.2 KiB
Go

// Copyright (c) 2020 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License-AGPL.txt in the project root for license information.
package cmd
import (
"fmt"
"log"
"net/http"
"net/http/httputil"
"net/url"
"os"
"strconv"
"github.com/google/tcpproxy"
"github.com/gorilla/handlers"
"github.com/spf13/cobra"
)
var rewriteHostHeader bool
var portFwdCmd = &cobra.Command{
Use: "forward-port <local-port> [target-port]",
Short: "Makes a port available on 0.0.0.0 so that it can be exposed to the internet",
Long: ``,
Args: cobra.RangeArgs(1, 2),
Run: func(cmd *cobra.Command, args []string) {
srcp, err := strconv.ParseUint(args[0], 10, 16)
if err != nil {
log.Fatalf("local-port cannot be parsed as int: %s", err)
os.Exit(-1)
return
}
trgp := srcp + 1
if len(args) > 1 {
var err error
trgp, err = strconv.ParseUint(args[1], 10, 16)
if err != nil {
log.Fatalf("target-port cannot be parsed as int: %s", err)
os.Exit(-1)
return
}
}
if rewriteHostHeader {
remote, _ := url.Parse(fmt.Sprintf("http://localhost:%d", srcp))
host := fmt.Sprintf("localhost:%d", srcp) // Spec: https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.23
proxy := httputil.NewSingleHostReverseProxy(remote)
originalDirector := proxy.Director
proxy.Director = func(r *http.Request) {
originalDirector(r)
r.Host = host
}
// we want both X-Forwarded-Proto AND X-Forwarded-Host to reach the backend
http.Handle("/", handlers.ProxyHeaders(http.HandlerFunc(proxy.ServeHTTP)))
fmt.Printf("Proxying HTTP traffic: 0.0.0.0:%d -> 127.0.0.1:%d (with host rewriting)\n", trgp, srcp)
err = http.ListenAndServe(fmt.Sprintf(":%d", trgp), nil)
if err != nil {
log.Fatalf("reverse proxy: %s", err)
}
return
}
var p tcpproxy.Proxy
p.AddRoute(fmt.Sprintf(":%d", trgp), tcpproxy.To(fmt.Sprintf("127.0.0.1:%d", srcp)))
fmt.Printf("Forwarding traffic: 0.0.0.0:%d -> 127.0.0.1:%d\n", trgp, srcp)
log.Fatal(p.Run())
},
}
func init() {
rootCmd.AddCommand(portFwdCmd)
portFwdCmd.Flags().BoolVarP(&rewriteHostHeader, "rewrite-host-header", "r", false, "rewrites the host header of passing HTTP requests to localhost")
}