Question

I have a problem with getting piping to work with paramiko.

This works:

ssh = paramiko.SSHClient()
[...]
stdin, stdout, stderr = ssh.exec_command("find /tmp")
stdout.read()

This does not work (blocks forever on stdout.read()):

[...]
stdin, stdout, stderr = ssh.exec_command("bash -")
stdin.write("find /tmp\n")
stdin.close()
stdout.read()

Any ideas?

EDIT:

I looked at the source code for paramiko, and ChannelFile.close does not really do anything in terms of communication. So I looked at the channel API, and this seems to work:

stdin.write("find /tmp\n")
stdin.flush()
stdin.channel.shutdown_write()
stdout.read()

Answer 1

With some investigation, it appears that stdin.close() does not actually end the bash session. To do that, you could use the bash command exit (stdin.write('exit\n')) or dig into the paramiko Channel object underneath the stdin object:

stdin.channel.shutdown_write()

If you’d like the bash session to continue for another command, you’ll need to use the channel object directly. The documentation for Channel mentions recv_ready(self) and recv(self, nbytes) which will allow you t check for the data before you try to get it.