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"""Example script for non-blocking execute.

Note that `ssh2.utils.wait_socket` is not a co-operative routine and will block

the main thread for up to <timeout> (default 1sec). Use for testing purposes

only."""

from __future__ import print_function

import argparse

import socket

import os

import pwd

from select import select

from ssh2.session import Session

# from ssh2.utils import wait_socket

from ssh2.error_codes import LIBSSH2_ERROR_EAGAIN

from ssh2.session import LIBSSH2_SESSION_BLOCK_INBOUND, \

LIBSSH2_SESSION_BLOCK_OUTBOUND

USERNAME = pwd.getpwuid(os.geteuid()).pw_name

parser = argparse.ArgumentParser()

parser.add_argument('cmd', help="Command to run")

parser.add_argument('--host', dest='host',

default='localhost',

help='Host to connect to')

parser.add_argument('--port', dest='port', default=22,

help="Port to connect on", type=int)

parser.add_argument('-u', dest='user', default=USERNAME,

help="User name to authenticate as")

def wait_socket(_socket, session, timeout=1):

"""Helper function for testing non-blocking mode.

This function blocks the calling thread for <timeout> seconds -

to be used only for testing purposes.

Also available at `ssh2.utils.wait_socket`

"""

directions = session.block_directions()

if directions == 0:

return 0

readfds = [_socket] \

if (directions & LIBSSH2_SESSION_BLOCK_INBOUND) else ()

writefds = [_socket] \

if (directions & LIBSSH2_SESSION_BLOCK_OUTBOUND) else ()

return select(readfds, writefds, (), timeout)

def main():

args = parser.parse_args()

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

sock.connect((args.host, args.port))

s = Session()

s.handshake(sock)

# Agent connections cannot be used as non-blocking

s.agent_auth(args.user)

# Now we can set non-blocking mode

s.set_blocking(False)

chan = s.open_session()

while chan == LIBSSH2_ERROR_EAGAIN:

print("Would block on session open, waiting for socket to be ready")

wait_socket(sock, s)

chan = s.open_session()

while chan.execute(args.cmd) == LIBSSH2_ERROR_EAGAIN:

print("Would block on channel execute, waiting for socket to be ready")

wait_socket(sock, s)

while chan.wait_eof() == LIBSSH2_ERROR_EAGAIN:

print("Waiting for command to finish")

wait_socket(sock, s)

size, data = chan.read()

while size == LIBSSH2_ERROR_EAGAIN:

print("Waiting to read data from channel")

wait_socket(sock, s)

size, data = chan.read()

while size > 0:

print(data)

size, data = chan.read()

if __name__ == "__main__":

main()