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='')

        yield from stdout.channel.wait_closed()

        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
  • OpenSSH-compatible direct and forwarded UNIX domain socket channels
  • Local and remote TCP/IP port forwarding
  • Local and remote UNIX domain socket 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
• Support for accessing keys managed by ssh-agent
• OpenSSH-style ssh-agent forwarding support
• 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) 2013-2016 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
• cryptography (PyCA) 1.1 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:

bcrypt

libnacl

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

pip install 'asyncssh[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.

Installing the development branch

If you would like to install the development branch of asyncssh directly from Github, you can use the following command to do this:

pip install git+https://github.com/ronf/asyncssh@develop

Mailing Lists

Three mailing lists are available for AsyncSSH:

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