How to run the commands inside the mininet prompt using python scripts from outside

Question

I am new to mininet. I want to run the mininet commands to run from the python scripts like "nodes","dump". I can create the topology but cannot use these commands through my script. I am using Ubuntu 14.04.

import subprocess as sb
import os
print "Single Switch and 4 Hosts per switch topology"
print "Creation of topology"
os.system(" sudo mn --topo = single,4",shell=True)
os.system("nodes")

Error:

sh: 1: nodes: not found
32512

I do not want to create a topology through python script, I only want to use the mininet commands.

mininet has a pythonic API. Is there a reason you want to invoke it using bash? — nir0s, Mar 13 '17 at 08:13

score 3 · Answer 1 · answered Mar 13 '17 at 09:40

As nirOs suggested , you should use the Mininet Python Library . Read Through https://github.com/mininet/mininet/wiki/Introduction-to-Mininet to get a better idea on how to create Topologies . Once Created you can use hostObject.cmd('your command goes here') . Each host in mininet is created with its own namespace . This "cmd" executes the given command in the host's namespace. For Example : host1.cmd("ifconfig") #this returns the IP information of the host

score 2 · Answer 2 · answered Mar 31 '17 at 16:26

2

Glad I found this question. I have a sub-question of a very similar nature. I understand that you can execute a command into the mininet CLI from python using e.g. h1.cmd('ifconfig') , but is there a way to do the same from python to the mininet> prompt ? i.e. not pointing it to a specific host in the topology (I am simulating faults so some hosts are disconnected). Something like net.cmd('python module.py') ? @Abhimanyu singh @nir0s

answered Mar 31 '17 at 16:26

Ahmed Ayman Ibrahim

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I would suggest you ask this as a new question . With specific examples of what you want to do . – Abhimanyu singh Apr 01 '17 at 06:45
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@Ahmed did you find an answer for the question? – mh-firouzjah Jan 19 '21 at 19:30

score 1 · Accepted Answer · edited May 23 '17 at 12:02

1

The problem is that mininet is an interactive CLI. You can't simply call it and then pass another command as an interactive CLI is blocking.

There are ways to solve that. Look here: Wrapping an interactive CLI in python

and check pexpect to more comfortably interact with interactive CLI's.

edited May 23 '17 at 12:02

Community

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answered Mar 13 '17 at 08:15

nir0s

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How to run the commands inside the mininet prompt using python scripts from outside

3 Answers3