In Python, how do I get a list of all partitions in Mac OS X?

Question

I have a similar question to the one asked here: Find size and free space of the filesystem containing a given file, but that question assumes you already know something about the system.

I have a task: for an undetermined number of machines, including new ones that are deployed regularly, I have/need a python script that can report to me if any of the partitions are too full. (Yes, it's deployed by icinga2).

What I don't do is hand craft and personalize the arguments to the script for every machine to inform it of the partitions I want checked; I run the script and it just reports to me on all of the extant partitions on the system. I let the system itself be the authority on itself rather than externally define what partitions to check. This works okay in linux, and as the answer linked above shows, in linux we can parse a file in /proc to get an authoritative list.

But what I'm lacking is a way to get a reliable list of partitions in Mac OS X from python.

Mac OS X doesn't have /proc, so parsing that won't work. I'd rather not call on an external binary, as my goal is to build my python script to run on both linux and mac clients. Any ideas?

Answer 1

Since you want a cross platform (Mac and Linux) option, you can use the df command which is available on both platforms. You can access it through subprocess.

I've tested this for both OS X 10.11 and Ubuntu Linux 15

import subprocess

process = subprocess.Popen(['df -h | awk \'{print $(NF-1),$NF}\''], stdout=subprocess.PIPE, shell=True)
out, err = process.communicate()
out = out.splitlines()[1:] # grab all the lines except the header line
results = {}
for i in out:
    tmp = i.split(' ')
    results[tmp[1]] = tmp[0]

for key, value in results.items():
    print key + " is " + str(value) +" full"

Output on Mac

/dev is 100% full
/net is 100% full
/ is 82% full
/home is 100% full

Output on Linux

/dev is 1% full
/run/lock is 0% full
/run is 1% full
/ is 48% full

Here is how you can do it without awk

import subprocess

process = subprocess.Popen(['df', '-h'], stdout=subprocess.PIPE)
out, err = process.communicate()
out = out.splitlines()[1:] # grab all the lines except the header line

for i in out:
    tmp = i.split(' ')
    tmp2 = []
    for x in tmp:
        if x != '':
            tmp2.append(x)
    print tmp2[-1] + " is " + tmp2[-2] + " full" 

Answer 2

I don't believe there is a uniform, cross-platform way to do this but you can use the subprocess module and call the command $ diskutil list like this for OS X

import subprocess
p = subprocess.Popen(['diskutil', 'list'], stdout=subprocess.PIPE)
o = p.stdout.read()

o will contain the output of the diskutil command.