28
votes

I'm trying to create a function that I can call on a timed basis to check for good ping and return the result so I can update the on-screen display. I am new to python so I don't fully understand how to return a value or set a variable in a function.

Here is my code that works:

import os
hostname = "google.com"
response = os.system("ping -c 1 " + hostname)
if response == 0:
    pingstatus = "Network Active"
else:
    pingstatus = "Network Error"

Here is my attempt at creating a function:

def check_ping():
    hostname = "google.com"
    response = os.system("ping -c 1 " + hostname)
    # and then check the response...
    if response == 0:
        pingstatus = "Network Active"
    else:
        pingstatus = "Network Error"

And here is how I display pingstatus:

label = font_status.render("%s" % pingstatus, 1, (0,0,0))

So what I am looking for is how to return pingstatus from the function. Any help would be greatly appreciated.

6
...return pingstatus? - jonrsharpe
To learn how to call functions and return values, I recommend the Python Tutorial. - Kevin
At first I was going to suggest a pure-python scheme (without shelling to the underlying OS) but then I saw the hassle/pain in the other thread: stackoverflow.com/questions/2953462/pinging-servers-in-python - MarkHu

6 Answers

40
votes

It looks like you want the return keyword

def check_ping():
    hostname = "taylor"
    response = os.system("ping -c 1 " + hostname)
    # and then check the response...
    if response == 0:
        pingstatus = "Network Active"
    else:
        pingstatus = "Network Error"

    return pingstatus

You need to capture/'receive' the return value of the function(pingstatus) in a variable with something like:

pingstatus = check_ping()

NOTE: ping -c is for Linux, for Windows use ping -n

Some info on python functions:

http://www.tutorialspoint.com/python/python_functions.htm

http://www.learnpython.org/en/Functions

It's probably worth going through a good introductory tutorial to Python, which will cover all the fundamentals. I recommend investigating Udacity.com and codeacademy.com

18
votes

Here is a simplified function that returns a boolean and has no output pushed to stdout:

import subprocess, platform
def pingOk(sHost):
    try:
        output = subprocess.check_output("ping -{} 1 {}".format('n' if platform.system().lower()=="windows" else 'c', sHost), shell=True)

    except Exception, e:
        return False

    return True
13
votes

Adding on to the other answers, you can check the OS and decide whether to use "-c" or "-n":

import os, platform
host = "8.8.8.8"
os.system("ping " + ("-n 1 " if  platform.system().lower()=="windows" else "-c 1 ") + host)

This will work on Windows, OS X, and Linux

You can also use sys:

import os, sys
host = "8.8.8.8"
os.system("ping " + ("-n 1 " if  sys.platform().lower()=="win32" else "-c 1 ") + host)
5
votes

Try this

def ping(server='example.com', count=1, wait_sec=1):
    """

    :rtype: dict or None
    """
    cmd = "ping -c {} -W {} {}".format(count, wait_sec, server).split(' ')
    try:
        output = subprocess.check_output(cmd).decode().strip()
        lines = output.split("\n")
        total = lines[-2].split(',')[3].split()[1]
        loss = lines[-2].split(',')[2].split()[0]
        timing = lines[-1].split()[3].split('/')
        return {
            'type': 'rtt',
            'min': timing[0],
            'avg': timing[1],
            'max': timing[2],
            'mdev': timing[3],
            'total': total,
            'loss': loss,
        }
    except Exception as e:
        print(e)
        return None
0
votes

This function will test ping for given number of retry attempts and will return True if reachable else False -

def ping(host, retry_packets):
    """Returns True if host (str) responds to a ping request."""

    # Option for the number of packets as a function of
    param = '-n' if platform.system().lower() == 'windows' else '-c'

    # Building the command. Ex: "ping -c 1 google.com"
    command = ['ping', param, str(retry_packets), host]
    return subprocess.call(command) == 0

# Driver Code
print("Ping Status : {}".format(ping(host="xx.xx.xx.xx", retry_packets=2)))

Output :

Pinging xx.xx.xx.xx with 32 bytes of data:
Reply from xx.xx.xx.xx: bytes=32 time=517ms TTL=60
Reply from xx.xx.xx.xx: bytes=32 time=490ms TTL=60

Ping statistics for xx.xx.xx.xx:
     Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
     Minimum = 490ms, Maximum = 517ms, Average = 503ms
Ping Status : True

Note : Change xx.xx.xx.xx with your IP

-2
votes

This is my version of check ping function. May be if well be usefull for someone:

def check_ping(host):
if platform.system().lower() == "windows":
response = os.system("ping -n 1 -w 500 " + host + " > nul")
if response == 0:
return "alive"
else:
return "not alive"
else:
response = os.system("ping -c 1 -W 0.5" + host + "> /dev/null")
if response == 1:
return "alive"
else:
return "not alive"