从python切换到另一台机器时转移标准输入

Question

I am trying to use SSH as a socks proxy to another machine, then ask the user if he wants to proceed. so I use:

proxy_cmd = "ssh -o 'StrictHostKeyChecking no' -i " + key_filename + ' -D 9998 ubuntu@' + ip_address    
subprocess.Popen(proxy_cmd, shell=True,  stdout=subprocess.PIPE)

if not raw_input('would you like to proceed?(y)')=='y':
    sys.exit()

and I get:

IOError: [Errno 11] Resource temporarily unavailable

I assume that's because the ssh is open and it is capturing stdin or something. I just don't know how to bypass this (I have no need to send input to the ssh, I just want it open for Selenium to use later) How can I do this?

Answer 1

If you want to keep stdin available to your Python program, then you'll have to redirect stdin for the ssh process even if you have no intention of using it, with something like...

subprocess.Popen(proxy_cmd,
                 shell=True,
                 stdin=subprocess.PIPE,
                 stdout=subprocess.PIPE)

Note that the subprocess module will retain a reference to the Popen object in the subprocess._active list, but you may also want to bind the resulting Popen object to a variable so you can perform operations on it later.