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Miki Tebeka committed d817693

Initial code from http://bit.ly/Oc1YtF (Roger Peppe)

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Files changed (1)

+/* Proxy TCP between two servers. Allow you to deploy new code to one server then switch traffic to it without downtime.
+
+Original code by Roger Peppe at http://bit.ly/Oc1YtF
+*/
+package main
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"os"
+)
+
+func main() {
+	if len(os.Args) != 3 {
+		fatal("usage: netfwd local remote")
+	}
+	localAddr := os.Args[1]
+	remoteAddr := os.Args[2]
+	local, err := net.Listen("tcp", localAddr)
+	if local == nil {
+		fatal("cannot listen: %v", err)
+	}
+	for {
+		conn, err := local.Accept()
+		if conn == nil {
+			fatal("accept failed: %v", err)
+		}
+		go forward(conn, remoteAddr)
+	}
+}
+
+func forward(local net.Conn, remoteAddr string) {
+	remote, err := net.Dial("tcp", "", remoteAddr)
+	if remote == nil {
+		fmt.Fprintf(os.Stderr, "remote dial failed: %v\n", err)
+		return
+	}
+	go io.Copy(local, remote)
+	go io.Copy(remote, local)
+}
+
+func fatal(s string, a ...interface{}) {
+	fmt.Fprintf(os.Stderr, "netfwd: %s\n", fmt.Sprintf(s, a))
+	os.Exit(2)
+}