Simple 'launchctl list' parser

launchctl.py

#!/usr/bin/env python3

import pprint,re,subprocess,sys

#
# Simple parser for 'launchctl list <service>' output
# 
# This works for simple outputs (which is true in most cases) but will fail for 
# complex outputs - in particular nested arrays/dicts
#

LAUNCHCTL_RE = re.compile(r''' 
                               "(\S*?)"\s+=\s+"(.*?)";$         # "key" = "<string>";
                               |
                               "(\S*?)"\s+=\s+(\d+?);$          # "key" = <int>;
                               |
                               "(\S*?)"\s+=\s+(true|false);$    # "key" = <bool>;
                               |
                               "(\S*?)"\s+=\s+(\S+);$           # "key" = <literal>;
                               |
                               "(\S*?)"\s+=\s+\((.*?)\);$       # "key" = ( <array>... );
                               |
                               "(\S*?)"\s+=\s+\{(.*?)\};$       # "key" = { <dict>... };
                           ''',
                          re.MULTILINE|re.DOTALL|re.VERBOSE)

def parse_launchctl_re(m):
    (s_key,s_val,i_key,i_val,b_key,b_val,l_key,l_val,a_key,a_val,d_key,d_val) = m
    if s_key:
        return (s_key,s_val)
    elif i_key:
        return (i_key,int(i_val))
    elif b_key:
        return (b_key,b_val == 'true')
    elif l_key:
        return (l_key,l_val)
    elif a_key:
        return (a_key,re.findall(r'"(.*?)";',a_val))
    elif d_key:
        return (d_key,dict([parse_launchctl_re(m) for m in re.findall(LAUNCHCTL_RE,d_val)]))

def launchctl_status(service):
    status = subprocess.run(("/bin/launchctl","list",service),capture_output=True)
    if status.returncode != 0:
        raise ValueError(status.stderr.decode().strip())
    else:
        return dict([parse_launchctl_re(m) for m in LAUNCHCTL_RE.findall(status.stdout.decode())])

if __name__ == '__main__':
    try:
        service = sys.argv[1]
        pprint.pprint(launchctl_status(service))
    except IndexError:
        print(f"Usage: {sys.argv[0]} <service>")