Go で 80 番以下のポートを listen するためのスクリプト

bind_and_setuser.py

#!/usr/bin/python

from __future__ import print_function

import os
import pwd
import socket
import sys


def bind_and_exec(host, port, uid, gid, cmd):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.bind((host, port))
    sock.listen(2048)
    if hasattr(sock, 'set_inheritable'):  # Python 3.4
        sock.set_inheritable(True)
    fd = sock.fileno()

    os.setgid(gid)
    os.setuid(uid)

    for i in range(1, len(cmd)):
        cmd[i] = cmd[i].replace('$FD', str(fd))
    print("executing:", cmd)
    os.execvp(cmd[0], cmd)


def main():
    if len(sys.argv) < 4:
        sys.exit("usage: bind_and_setuser.py address:port user cmd...")
    host, port = sys.argv[1].rsplit(':', 1)
    port = int(port)

    pw = pwd.getpwnam(sys.argv[2])
    bind_and_exec(host, port, pw.pw_uid, pw.pw_gid, sys.argv[3:])


if __name__ == '__main__':
    main()

circus.ini

[circus]
statsd = 1

[watcher:echo-go]
cmd = ./server_go -fd $(circus.sockets.echo)
use_sockets = True
uid = myservice
gid = myservice

[socket:echo]
host = 0.0.0.0
port = 80

echo-server.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"os"
)

func echo_handler(conn net.Conn) {
	defer conn.Close()
	buf := make([]byte, 128)
	for {
		n, err := conn.Read(buf)
		if err != nil {
			log.Println(err)
			return
		}
		fmt.Println("Received: ", string(buf[:n]))
		conn.Write(buf[:n])
	}
}

func main() {
	fd := flag.Uint("fd", 0, "fd to listen and serve")
	port := flag.Uint("port", 0, "port to listen and serve")
	flag.Parse()

	var l net.Listener
	var err error

	if *fd != 0 {
		l, err = net.FileListener(os.NewFile(uintptr(*fd), ""))
		if err != nil {
			log.Panic(err)
		}
	} else if *port != 0 {
		l, err = net.ListenTCP("tcp", &net.TCPAddr{Port: int(*port)})
		if err != nil {
			log.Panic(err)
		}
	} else {
		fmt.Println("fd or port required.")
		return
	}
	for {
		conn, e := l.Accept()
		if e != nil {
			log.Fatal(e)
			return
		}
		go echo_handler(conn)
	}
}