pysshpass 0.1.0

Python-based SSH client designed to offer a multiplatform alternative to `sshpass`.

pysshpass: A Multiplatform SSH Automation Utility

Overview

pysshpass is a Python-based SSH client designed to offer a multiplatform alternative to sshpass. This utility aims to address two core challenges:

1. Windows Compatibility: Native sshpass options are limited on Windows, and pysshpass serves as a versatile replacement.
2. Specialized Devices Support: Network devices like PaloAlto Firewalls, Cloudgenix SD-WAN routers, and F5 load balancers often have unique command-line interfaces and large outputs, which are not fully supported by libraries like Netmiko.

Key Features

• Comma-Delimited Commands: The utility allows for executing multiple commands in sequence, ideal for devices requiring a series of commands for configuration or data retrieval.

• Prompt Controls: The script supports custom prompts and prompt counts, offering more control over when to exit the shell. This is particularly useful for devices with multi-modal interfaces (e.g., F5's tmsh, bash, and imsh).

• Timeout Management: A timeout feature ensures that the utility doesn't hang while waiting for device responses, making it more robust and production-ready.

Example usage

pysshpass -h "172.16.1.101" -u "cisco" -p "cisco" -c "term len 0,show users,show run,show cdp neigh,show int desc" --invoke-shell --prompt "#" --
prompt-count 4 -t 15

Home Network on GNS3 - Where Scott Plays

usa1-rtr-1#term len 0
usa1-rtr-1#show users
    Line       User       Host(s)              Idle       Location
   0 con 0                idle                 10:38:21
*  2 vty 0     cisco      idle                 00:00:00 10.0.0.191

  Interface    User               Mode         Idle     Peer Address

usa1-rtr-1#show run
Building configuration...

Current configuration : 2137 bytes
!
! Last configuration change at 18:32:41 UTC Sun Oct 22 2023 by cisco
upgrade fpd auto
<output truncated>

Use-Cases

This utility is particularly useful for:

• Automating tasks on devices with large configuration outputs
• Working with multi-modal command-line interfaces
• Gathering information during network audits, especially for devices not well-supported by existing automation libraries

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CLI Usage

>python pysshpass.py --help
Usage: pysshpass.py [OPTIONS]

Options:
  -h, --host TEXT         SSH Host (ip:port)  [required]
  -u, --user TEXT         SSH Username  [required]
  -p, --password TEXT     SSH Password  [required]
  -c, --cmds TEXT         Commands to run, separated by comma
  --invoke-shell          Invoke shell before running the command
  --prompt TEXT           Prompt to look for before breaking the shell     
  --prompt-count INTEGER  Number of prompts to look for before breaking the
                          shell
  -t, --timeout INTEGER   Command timeout duration in seconds
  --help                  Show this message and exit.

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Function read_output

• This function reads the output of the SSH session in real-time and prints it to the standard output.
• It also checks for a user-defined prompt (e.g., $, #, etc.) to decide when to stop reading the output and exit the loop.

Function ssh_client

• It accepts multiple command-line arguments, such as host, username, and password, using the click library.
• The invoke_shell flag specifies whether to create an interactive SSH session or just execute commands.
• The prompt and prompt_count options are useful when invoke_shell is set, allowing the script to break the shell after a specific number of prompts.

Thread usage

• A daemon thread (read_thread) runs in the background to handle the reading of output from the SSH session.

User Prompt Management

• The code uses a queue (output_queue) to communicate between the main function and the thread that reads the SSH output.
• A timer (timeout) ensures the script doesn't hang indefinitely waiting for a prompt.

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