Paramiko Expect

Artwork courtesy of Open Clip Art Library

Repository Archived

This project originally started as a POC while I was automating some tasks on Cisco CDS devices in my operations role. While the library worked well, I didn't actually get to use it much myself as I moved onto an engineering role soon after. Since then, Israel Fruchter has been kindly leading maintenance of the project.

Unfortunately, Israel is also no longer using this project and no suitable maintainers were found to take over.

As such, I have decided to archive the project and officially call it discontinued. The community is welcome to fork the project and continue its development if required.

Introduction

Paramiko Expect provides an expect-like extension for the Paramiko SSH library which allows scripts to fully interact with hosts via a true SSH connection.

The class is constructed with an SSH Client object (this will likely be extended to support a transport in future for more flexibility).

Quick Start

To install paramiko-expect, simply run the following at your prompt:

# from pypi
pip install paramiko-expect

# from source
pip install git+https://github.com/fgimian/paramiko-expect.git

So let's check out how it works in general (please see paramiko_expect-demo.py for the complete code):

# Connect to the host
client.connect(hostname=hostname, username=username, password=password)

# Create a client interaction class which will interact with the host
interact = SSHClientInteraction(client, timeout=10, display=True)
interact.expect(prompt)

# Run the first command and capture the cleaned output, if you want the output
# without cleaning, simply grab current_output instead.
interact.send('uname -a')
interact.expect(prompt)
cmd_output_uname = interact.current_output_clean

# Now let's do the same for the ls command but also set a timeout for this
# specific expect (overriding the default timeout)
interact.send('ls -l /')
interact.expect(prompt, timeout=5)
cmd_output_ls = interact.current_output_clean

# To expect multiple expressions, just use a list.  You can also selectively
# take action based on what was matched.

# Method 1: You may use the last_match property to find out what was matched
interact.send('~/paramiko_expect-demo-helper.py')
interact.expect([prompt, 'Please enter your name: '])
if interact.last_match == 'Please enter your name: ':
    interact.send('Fotis Gimian')
    interact.expect(prompt)

# Method 2: You may use the matched index to determine the last match (like pexpect)
interact.send('~/paramiko_expect-demo-helper.py')
found_index = interact.expect([prompt, 'Please enter your name: '])
if found_index == 1:
    interact.send('Fotis Gimian')
    interact.expect(prompt)

# Send the exit command and expect EOF (a closed session)
interact.send('exit')
interact.expect()

# Print the output of each command
print '-'*79
print 'Cleaned Command Output'
print '-'*79
print 'uname -a output:'
print cmd_output_uname
print 'ls -l / output:'
print cmd_output_ls

Important: Before running this script, be sure to place paramiko_expect-demo-helper.py in ~.

The print statements at the bottom of the script provide the following output:

-------------------------------------------------------------------------------
Cleaned Command Output
-------------------------------------------------------------------------------
uname -a output:
Linux fotsies-ubuntu-testlab 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

ls -l / output:
total 77
drwxr-xr-x  2 root root  4096 May  1 22:21 bin
drwxr-xr-x  4 root root  1024 May  1 22:22 boot
drwxr-xr-x 15 root root  4300 Jun 12 15:00 dev
drwxr-xr-x 90 root root  4096 Jun 12 16:45 etc
drwxr-xr-x  4 root root  4096 May  1 23:37 home
lrwxrwxrwx  1 root root    33 May  1 22:18 initrd.img -> /boot/initrd.img-3.2.0-23-generic
drwxr-xr-x 18 root root  4096 May  1 22:21 lib
drwxr-xr-x  2 root root  4096 May  1 22:17 lib64
drwx------  2 root root 16384 May  1 22:17 lost+found
drwxr-xr-x  4 root root  4096 May  1 22:18 media
drwxr-xr-x  2 root root  4096 Apr 19 19:32 mnt
drwxr-xr-x  2 root root  4096 May  1 22:17 opt
dr-xr-xr-x 84 root root     0 Jun 12 15:00 proc
drwx------  3 root root  4096 May 30 23:32 root
drwxr-xr-x 15 root root   560 Jun 12 17:02 run
drwxr-xr-x  2 root root  4096 Jun  4 20:59 sbin
drwxr-xr-x  2 root root  4096 Mar  6 04:54 selinux
drwxr-xr-x  2 root root  4096 May  1 22:17 srv
drwxr-xr-x 13 root root     0 Jun 12 15:00 sys
drwxrwxrwt  2 root root  4096 Jun 12 16:17 tmp
drwxr-xr-x 10 root root  4096 May  1 22:17 usr
drwxr-xr-x 12 root root  4096 Jun 12 13:16 var
lrwxrwxrwx  1 root root    29 May  1 22:18 vmlinuz -> boot/vmlinuz-3.2.0-23-generic

For interacting with tail-like scripts, we can use the tail function (please see paramiko_expect-tail-demo.py for the complete code):

# Connect to the host
client.connect(hostname=hostname, username=username, password=password)

# Create a client interaction class which will interact with the host
interact = SSHClientInteraction(client, timeout=10, display=False)
interact.expect(prompt)

# Send the tail command
interact.send('tail -f /var/log/auth.log')

# Now let the class tail the file for us
interact.tail(line_prefix=hostname+': ')

The true power of the tail function will become more apparent when you check out the Multi-SSH library. Ever thought about tailing a log on multiple servers? Well dream no more my friend, it's here!

Tests

Not full coverage yet, and assumes you have docker setup:

pip install -r requirements-test.txt
docker run -d -p 2222:22 -v `pwd`/examples:/examples -v `pwd`/test/id_rsa.pub:/root/.ssh/authorized_keys  docker.io/panubo/sshd
pytest -s --cov paramiko_expect --cov-report term-missing

Contributions

• Israel Fruchter (@fruch) - Tests / CI / Uploads to Pypi
• Kiseok Kim (@kiseok7) - Vagrent image

License

Paramiko Expect is released under the MIT license. Please see the LICENSE file for more details.