How to use paramiko with asyncio and asyncssh

For handling SSH connections and commands asynchronously in Python, AsyncSSH is an efficient and comprehensive library tailored to integrate with asyncio. Unlike Paramiko, which is synchronous, AsyncSSH is built specifically for asynchronous operations, making it a better fit for asyncio tasks.

Getting Started with AsyncSSH

Installation

Before you start, install AsyncSSH using pip:

pip install asyncssh

Basic AsyncSSH Connection

Here’s a simple way to establish an SSH connection and execute a command using AsyncSSH:


import asyncio, asyncssh, sys

async def run_client():
    try:
        async with asyncssh.connect('hostname') as conn:
            result = await conn.run('ls', check=True)
            print(result.stdout, end='')
    except (OSError, asyncssh.Error) as exc:
        sys.exit('SSH connection failed: ' + str(exc))

asyncio.run(run_client())

Authentication Handling

Authentication can be handled by providing additional parameters during the connection setup:


async with asyncssh.connect('hostname', username='your_username', password='your_password') as conn:
    # Connection code here

Or using a private key:


async with asyncssh.connect('hostname', username='your_username', client_keys=['/path/to/private/key']) as conn:
    # Connection code here

Advanced Usage and Features

AsyncSSH isn’t just for executing commands; it supports a wide array of SSH-related tasks:

Port forwarding
Running an SSH server
Handling multiple sessions
File transfers using SFTP

Considerations When Using AsyncSSH

Asynchronous Nature: Remember that all operations are non-blocking and should be handled within async functions.
Error Handling: Properly handle exceptions and errors especially when dealing with network operations.
Compatibility: Ensure that AsyncSSH is compatible with your server’s SSH implementation and version.

Why Not Paramiko with Asyncio?

While it’s technically possible to integrate Paramiko (a synchronous library) with asyncio by running it in a separate thread, this approach is more complex and less efficient than using AsyncSSH. AsyncSSH’s native asynchronous support provides a more streamlined and robust solution for SSH operations in asynchronous Python applications.