#!/usr/bin/perl -w

# Check a PEM certificate
# --what: what to monitor. Only expire is supported for now, and returns the number of day before expiration
# --cert: the path to the certificate you want to check

use strict;
use warnings;
use Crypt::OpenSSL::X509;
use Date::Parse;
use Getopt::Long;

my $what = 'expire';
my $cert = '';

GetOptions(
    "cert=s" => \$cert,
    "what=s"  => \$what
);

die "Usage: $0 --what=status --cert=/path/to/pem/certificate\n" unless
    (-f $cert);

$cert = Crypt::OpenSSL::X509->new_from_file( "$cert" );
my $expire_in = int ((str2time($cert->notAfter())-time())/(3600*24));

if ($what eq 'expire'){
    print $expire_in;
}
else{
    die "Only expire is supported for now";
}