I've been using Paramiko today to work with a Python SSH connection, and it is useful.
However one thing I'd really like to be able to do over the SSH is to utilise some Pythonic sugar. As far as I can tell I can only use the inbuilt Paramiko functions, and if I want to anything using Python on the remote side I would need to use a script which I have placed on there, and call it.
Is there a way I can send Python commands over the SSH connection rather than having to make do only with the limitations of the Paramiko SSH connection? Since I am running the SSH connection through Paramiko within a Python script, it would only seem right that I could, but I can't see a way to do so.
RPyC could be what you're looking for. It gives you access to another machine's Python environment directly from the local script.
>>> import rpyc
>>> conn = rpyc.classic.connect("someremotehost.com")
>>> conn.modules.sys.path
['D:\\projects\\rpyc\\servers', 'd:\\projects', .....]
To establish a connection over SSL or SSH, see:
http://rpyc.sourceforge.net/docs/secure-connection.html#ssl
Well, that is what SSH created for - to be a secure shell, and the commands are executed on the remote machine (you can think of it as if you were sitting at a remote computer itself, and that either doesn't mean you can execute Python commands in a shell, though you're physically interact with a machine).
You can't send Python commands simply because Python do not have commands, it executes Python scripts.
So everything you can do is a "thing" that will make next steps:
Wrap a piece of Python code into file.
scp it to the remote machine.
Execute it there.
Remove the script (or cache it for further execution).
Basically shell commands are remote machine's programs themselves, so you can think of those scripts like shell extensions (python programs with command-line parameters, e.g.).
Related
I am working with Paramiko 2.7.1, using a simple client implementation for running commands on remote SSH servers.
On most of my hosts, it works great. Input commands go out, output (if exists) comes back.
One specific type of host (an IBM VIOS partition to be precise) is giving me headaches in that the commands execute, but the output is always empty.
I have used PuTTY in an interactive session to log all SSH packets and check for any differences and, at least during an interactive session, no differences present between a working and a non-working host.
I have enabled Paramiko logging with:
basicConfig(level=DEBUG)
logging.getLogger("paramiko").setLevel(logging.DEBUG)
log_to_file('ssh.log')
But the output doesn't dump each packet. I have done a search for any parameters or methods that would dump those packets but I've come up empty.
Wireshark is not an option since we are talking about an encrypted connection.
I would prefer to keep using exec_command instead of having to refactor everything and adapt to using an SSH shell.
So, in the end. Is there any way to dump the entire SSH session with Paramiko? I can handle either SSH packets or raw data.
Edit 1: I have remembered that PuTTY's plink.exe does ssh exec commands, so I used it to compare both SSH server's output and stumbled onto the solution to my base problem: https://www.ibm.com/support/pages/unable-execute-commands-remotely-vio-server-padmin-user-ssh
Still, I'd rather have captured the session with Paramiko, since I will not always be able to simulate with other tools...
In addition to enabling logging, call Transport.set_hexdump():
client.get_transport().set_hexdump(True)
Regarding your original problem, see also:
Command executed with Paramiko does not produce any output
Using fabric 2.4 and trying to set up ssh keys to remotely connect to various linux servers?
Python is new to me, I've followed example on this site and Read python doc but still unclear to me.
Currently running python on windows and my script is able to connect to remote linux servers because i have connection string defined as follows:
ssh_connect = Connection(host='servername', user='user1', connect_kwargs={'password': 'blahblah'})
I am running python script from my window server and instead of defining the connection string, I would like it to use ssh key. I have the id_rsa.pub file from the linux server. I would like to setup up on my windows box and have the script use that for connections?
You can always just pass a key via Fabric through it's command line arguments. This is definitely kind of a vague question, especially since it's running fabric on Windows, which to my knowledge is not technically supported by them, though it does work.
fab -i /Path/to/key
Source: fab --help and the official documentation here
I have a python script located on a remote server with SSH enabled. That script displays a lot of debug messages displayed while executing. I want to trigger this script using another python script which is on my local system and depending on the output of the earlier script, I want to proceed further. While doing all this, I want the display messages on the remote server to be displayed on my local system as well. Basically, I want to view whatever output is thrown by the remote script during the course of the script, on my local system. I am able to trigger the script using paramiko but I am neither able to check whether the script on the remote server is running nor am I able to view it's output. Is there any way to do it? Already tried conn.recv(65535) but to no avail.
In my experience I found python fabric module easier than using paramiko. If you want to execute local script on remote machine using fabric. You just need to upload them using put() and then call run() api.
http://docs.fabfile.org/en/1.14/api/core/operations.html#fabric.operations.put
I have a pretty simple task: using ssh, I want to create a tunnel that forwards traffic from my local machine to a specific port on a remote machine. I can do this from the command line:
ssh -N -L 123:127.0.0.1:456 user#remotehost
Then if I run:
telnet localhost 123
it's the equivalent of logging into remotehost and running
telnet 127.0.0.1 456
I've managed to do this with something along the lines of;
subprocess.Popen(['ssh', '-N', '-L', '%i:127.0.0.1:%i' % (new_port, old_port), ssh_user + '#' + ip_addr])
But now I want to move away from that and use only Python - no external processes.
I've tried using fabric.context_managers.remote_tunnel but unless I've misunderstood this is meant for creating a tunnel that starts at a remote location, not from the local machine. That is, it is the equivalent of SSHing into a remote machine and creating an SSH tunnel from there, which is silly for my purpose. I suppose I could set the remote host to actually be the local machine but this seems inefficient and honestly I don't even understand how to do that.
I've also tried forward.py on paramiko and it doesn't work because my private key is encrypted. I'd like to modify the script to handle that, and also just simplify it for my needs, but both the script and the paramiko library are daunting and I don't know how to begin.
Surely there's an easy way to do this? I seem to be so close yet so far.
What do you mean by "pure Python"? Subprocess is bundled with standard python installation.
Subprocess and Fabric are designed for such tasks, why would you want to move away from them?
If you have, minimal tasks to be performed remotely e.g. check memory, hostname, etc. you can go ahead with suprocess. However if you have some big requirements, I would suggest going with fabric.
For your purpose where you have to work on the same machine, why not use subprocess with check_call or Popen. As an alternative, you can change your code altogether so as to be able to get into Unix core to achieve what the Linux commands do.
I have been interested in finding an alternative to the UI in SAS for quite some time now. We license SAS on our server instead of our desktops, so furthermore we have to launch a remote desktop application to execute code.
I was able to use a Telnet connection instead to remotely connect to the server, and batch execute SAS programs. Then I was interested in whether a python script could be made to connect remotely, and batch execute code, and this script could be executed in jEdit as a BeanShell script.
So far, I have Python code which successfully opens and closes the Telnet connection. It can do basic shell functions like call "dir". However, when I pass the exact same line that I use to execute SAS from command prompt on the remote server with a telnet connection in Python, nothing happens.
Is it possible the server is preventing me from executing code from a script? I use a "read_until" statement for the prompt before running any code.
Here's a few ideas...
The issue you are having above may be related to Local Security Policy settings in Windows (if it is running on a windows server). I'm far from an expert on that stuff but I remember older SAS/Intranet installations required some rumaging around in there to get them working.
As an alternative to the approach you are trying above you could also setup a SAS session on the server that listens for incoming socket requests as per this article:
http://analytics.ncsu.edu/sesug/2000/p-1003.pdf
And finally... Not sure if this helps or not by I remotely execute SAS jobs using PSEXEC. A description of how I set it all up can be found here:
http://www.runsubmit.com/questions/260/hide-sas-batch-jobs-winxp
Good luck
This paper outlines how you can use a Python script to connect to a Unix server using SSH, copy the SAS program written locally onto the server, batch submit it, and download the results back to your local machine, all using a BeanShell macro script for jEdit.