如何使用Unix Socket在ruby和Python之间进行通信

Question

我试图在我的ruby进程和Python进程之间进行一些通信; 我想使用UNIX套接字.

目标:ruby进程"fork和exec"的Python进程.在ruby进程中,创建一个UNIX套接字对,并将其传递给Python.

Ruby代码(p.rb):

require 'socket'

r_socket, p_socket = Socket.pair(:UNIX, :DGRAM, 0)

# I was hoping this file descriptor would be available in the child process
pid = Process.spawn('python', 'p.py', p_socket.fileno.to_s)

Process.waitpid(pid)

Python代码(p.py):

import sys
import os
import socket

# get the file descriptor from command line
p_fd = int(sys.argv[1])

socket.fromfd(p_fd, socket.AF_UNIX, socket.SOCK_DGRAM)

# f_socket = os.fdopen(p_fd)
# os.write(p_fd, 'h')

命令行:

ruby p.rb

结果:

OSError: [Errno 9] Bad file descriptor

我希望ruby进程将文件描述符传递给python进程,以便这两个可以使用这些套接字发送数据.

所以,我的问题:

1)是否可以像上面那样在ruby和python进程之间传递打开的文件描述符？

2)如果我们可以在两个进程之间传递文件描述符,那么我的代码中有什么问题.

Answer 1

你很接近,但Ruby spawn默认关闭任何文件描述符> 2,除非你:close_others => false作为参数传递.查看文档:

http://apidock.com/ruby/Kernel/spawn

工作范例:

require 'socket'

r_socket, p_socket = Socket.pair(:UNIX, :DGRAM, 0)

pid = Process.spawn('python', 'p.py', p_socket.fileno.to_s,
                    { :close_others => false })

# Close the python end (we're not using it on the Ruby side)
p_socket.close

# Wait for some data
puts r_socket.gets

# Wait for finish
Process.waitpid(pid)

蟒蛇:

import sys
import socket

p_fd     = int(sys.argv[1])
p_socket = socket.fromfd(p_fd, socket.AF_UNIX, socket.SOCK_DGRAM)

p_socket.send("Hello world\n")

测试:

> ruby p.rb
Hello world