paramiko-expect

0.3.5 · active · verified Wed Apr 15

paramiko-expect is an expect-like extension for the Paramiko SSH library, enabling scripts to interact with remote hosts via a true SSH connection in an interactive, automated fashion. It's particularly useful for automating interactions with command-line applications, shell scripts, or network devices that require 'expect'-style responses to prompts. The current version is 0.3.5, and releases are infrequent, with the last update in late 2022.

Warnings

breaking Potential compatibility issues with newer Paramiko versions: paramiko-expect (v0.3.5) was last updated in November 2022. The underlying Paramiko library has had several major releases since then (e.g., Paramiko 3.x in December 2023), including dropping support for Python 2 and older Python 3 versions (<3.6). Using paramiko-expect with the very latest Paramiko releases might lead to unforeseen compatibility issues or unexpected behavior.
Fix: Pin your Paramiko dependency to a version known to be compatible with paramiko-expect v0.3.5 (e.g., Paramiko <3.0). If you require newer Paramiko features, thoroughly test for compatibility or consider alternatives.
gotcha Output cleaning can break with long commands due to TTY width: If a command sent via `send()` is long enough to wrap lines within the remote terminal's `tty_width`, the echoed command line may contain inserted spaces. This can cause `current_output_clean` to fail to correctly remove the echoed command, resulting in it appearing in your captured output or breaking subsequent `expect()` calls based on output patterns.
Fix: Adjust the `tty_width` parameter in `SSHClientInteraction` to match or exceed the maximum expected line length, or ensure your `expect()` patterns are robust enough to handle potential line wrapping in the echoed command.
gotcha Misunderstanding `expect()` patterns for multi-line output/prompts: When expecting a prompt or output that spans multiple lines, users sometimes create complex regex patterns or lists expecting every line. Often, `interact.expect()` only needs to match the *final* line or a unique part of the prompt to correctly identify the state, and over-specifying can lead to timeouts or incorrect matches.
Fix: Simplify `expect()` patterns to target only the distinctive end-of-prompt or end-of-output string. Test your patterns thoroughly to ensure they reliably match the desired state without being overly strict.
gotcha `SSHClientInteraction` requires a `paramiko.SSHClient` object: The `SSHClientInteraction` class is designed to wrap a `paramiko.SSHClient` instance. While the library's description mentions potential future support for `paramiko.Transport` objects, currently, passing a `Transport` object directly will result in an error or incorrect behavior.
Fix: Always initialize `SSHClientInteraction` with a fully connected `paramiko.SSHClient` object. Ensure the `SSHClient` object has already established a session with `client.connect()` before passing it to `SSHClientInteraction`.

Install

pip install paramiko-expect Install from PyPI

Imports

SSHClientInteraction

from paramiko_expect import SSHClientInteraction

Quickstart

This quickstart demonstrates how to establish an SSH connection using Paramiko, then wrap the SSHClient object with SSHClientInteraction to send commands and expect specific prompts. It prints the cleaned output of each command.

import paramiko
import os
from paramiko_expect import SSHClientInteraction

HOSTNAME = os.environ.get('SSH_HOSTNAME', 'localhost')
USERNAME = os.environ.get('SSH_USERNAME', 'testuser')
PASSWORD = os.environ.get('SSH_PASSWORD', 'testpass')
PROMPT = r'.*\$ ' # Example prompt for a Linux shell ending with $ or #

client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())

try:
    client.connect(hostname=HOSTNAME, username=USERNAME, password=PASSWORD, timeout=10)
    print(f"SSH connection established to {HOSTNAME}")

    with SSHClientInteraction(client, timeout=10, display=True) as interact:
        # Wait for the initial prompt after connection
        interact.expect(PROMPT)
        print(f"Initial prompt: {interact.last_match}")

        # Send a command and wait for the prompt again
        interact.send('uname -a')
        interact.expect(PROMPT)
        print(f"Uname output:\n{interact.current_output_clean}")

        # Send another command
        interact.send('echo Hello paramiko-expect!')
        interact.expect(PROMPT)
        print(f"Echo output:\n{interact.current_output_clean}")

finally:
    client.close()
    print("SSH connection closed.")

view raw JSON →