AsyncSSH: Asynchronous SSH for Python

AsyncSSH is a Python package which provides an asynchronous client and server implementation of the SSHv2 protocol on top of the Python 3.4+ asyncio framework.

import asyncio, asyncssh, sys

@asyncio.coroutine
def run_client():
    with (yield from asyncssh.connect('localhost')) as conn:
        stdin, stdout, stderr = yield from conn.open_session('echo "Hello!"')
        output = yield from stdout.read()
        print(output, end='')

        status = stdout.channel.get_exit_status()
        if status:
            print('Program exited with status %d' % status, file=sys.stderr)
        else:
            print('Program exited successfully')

asyncio.get_event_loop().run_until_complete(run_client())

Check out the examples to get started!

Features

• Full support for SSHv2 and SFTP client and server functions
  • Shell, command, and subsystem channels
  • Environment variables, terminal type, and window size
  • Direct and forwarded TCP/IP channels
  • Local and remote TCP/IP port forwarding
  • SFTP protocol version 3 with OpenSSH extensions
• Multiple simultaneous sessions on a single SSH connection
• Multiple SSH connections in a single event loop
• Byte and string based I/O with settable encoding
• A variety of key exchange, encryption, and MAC algorithms
• Support for gzip compression
  • Including OpenSSH variant to delay compression until after auth
• Password, public key, and keyboard-interactive user authentication methods
• Many types and formats of public keys and certificates
• OpenSSH-style known_hosts file support
• OpenSSH-style authorized_keys file support
• Compatibility with OpenSSH "Encrypt then MAC" option for better security
• Time and byte-count based session key renegotiation
• Designed to be easy to extend to support new forms of key exchange, authentication, encryption, and compression algorithms

License

This package is released under the following terms:

Copyright (c) 2013-2015 by Ron Frederick <[email protected]>. All rights reserved.

This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution and is available at:

http://www.eclipse.org/legal/epl-v10.html

For more information about this license, please see the Eclipse Public License FAQ.

Prerequisites

To use asyncssh, you need the following:

• Python 3.4 or later
• PyCrypto 2.6 or later and/or PyCA 0.6.1 or later

Installation

Install AsyncSSH by running:

pip install asyncssh

Optional Extras

There are some optional modules you can install to enable additional functionality:

• Install bcrypt from https://code.google.com/p/py-bcrypt if you want support for OpenSSH private key encryption.
• Install libsodium from https://github.com/jedisct1/libsodium and libnacl from https://github.com/saltstack/libnacl if you want support for curve25519 Diffie Hellman key exchange, ed25519 keys, and the chacha20-poly1305 cipher.

AsyncSSH defines the following optional PyPI extra packages to make it easy to install any or all of these dependencies:

pycrypto

pyca

bcrypt

libnacl

For example, to install all of these, you can run:

pip install 'asyncssh[pycrypto,pyca,bcrypt,libnacl]'

Note that you will still need to manually install the libsodium library listed above for libnacl to work correctly. Unfortunately, since libsodium is not a Python package, it cannot be directly installed using pip.

Mailing Lists

Three mailing lists are available for AsyncSSH:

• [email protected]: Project announcements
• [email protected]: Development discussions
• [email protected]: End-user discussions