check_mail_aliases

#!/usr/bin/env python3
#-------------------------------------------------------------------------------
##aptitude install python-nagiosplugin

import os
import sys
import subprocess
import argparse

#-------------------------------------------------------------------------------

_candebug = False
def candebug():
    global _candebug
    return _candebug
def setcandebug(value):
    global _candebug
    _candebug = value

def infomsg(msg):
    if candebug() == True:
        print(msg, flush=True)

def exitnagios(status,message):
    if status=="OK":
        exitcode = 0
    elif status=="WARNING":
        exitcode = 1
    elif status=="CRITICAL":
        exitcode = 2
    elif status=="UNKNOWN":
        exitcode = 3
    else:
        exitcode = 4
    print(status+": "+message, flush=True)
    sys.exit(exitcode)

#-------------------------------------------------------------------------------

def isfinal(parts):
    finals = ["localaccount@localhost"]
    return parts[0] in finals

def isexclusion(parts,customlines):
    exceptions = []+customlines
    exceptions.append(["mailer-daemon", "postmaster@localhost"])
    exceptions.append(["root", "localaccount@localhost"])
    #infomsg(exceptions)
    for exception in exceptions:
        if (exception[0] == parts[0]) and (exception[1] == parts[1]):
            return True
    return False

def isexpected(parts):
    return parts[1] == "root@localhost"

def domailaliasescall(customlines):
    try:
        aliasesfile = "/etc/aliases"
        if os.path.isfile(aliasesfile):
            errors = []
            exclusion = []
            expected = []
            handle = open(aliasesfile,"r")
            try:
                lines = handle.read().splitlines()
                for line in lines:
                    line = line.strip()
                    if len(line)>0:
                        if line[0] not in [";","#"]:
                            parts = line.split(":",1)
                            if len(parts)==2:
                                parts[0] = parts[0].strip()
                                parts[1] = parts[1].strip()
                                if parts[1].endswith("@localhost") == False:
                                    infomsg("ERROR -> "+str(parts))
                                    errors.append(line)
                                elif isfinal(parts) == True:
                                    infomsg("ERROR -> "+str(parts))
                                    errors.append(line)
                                elif isexclusion(parts,customlines):
                                    infomsg("EXCLUSION -> "+str(parts))
                                    exclusion.append(line)
                                elif isexpected(parts):
                                    infomsg("EXPECTED -> "+str(parts))
                                    expected.append(line)
                                else:
                                    infomsg("ERROR -> "+str(parts))
                                    errors.append(line)
                            else:
                                errors.append(line)
                                #infomsg("->"+line+"<-")
            finally:
                handle.close()
            if len(errors) == 0:
                exitnagios("OK","no issues found in "+aliasesfile+" | errors="+str(len(errors))+" exclusion="+str(len(exclusion))+" expected="+str(len(expected)))
            else:
                exitnagios("CRITICAL","issues found in "+aliasesfile+" -> "+" - ".join(errors)+" | errors="+str(len(errors))+" exclusion="+str(len(exclusion))+" expected="+str(len(expected)))
        else:
            exitnagios("CRITICAL","cannot find "+aliasesfile+" | errors=-1 exclusion=-1 expected=-1")
    except Exception as e:
        exitnagios("CRITICAL","unexpected exception "+str(e)+" | errors=-1 exclusion=-1 expected=-1")

#-------------------------------------------------------------------------------

def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("-®", "--debug",             action="store_true",  dest="debug",            default=False,                                help="be more verbose")
    parser.add_argument("-l", "--customlines",                             dest="customlines",      default="",                                   help="expected custom lines")

    args = parser.parse_args()
    
    return args

def main():
    args = parse_args()
    setcandebug(args.debug)
    customlines = []
    for entry in args.customlines.split(","):
        customlines.append(entry.strip().split(":"))
    infomsg("The custom lines are "+str(customlines))
    domailaliasescall(customlines)

if __name__ == "__main__":
    main()

#-------------------------------------------------------------------------------