Monitoring the systemd journal with Twisted

journalmon.py

from systemd import journal
from twisted.internet import reactor

UNITS = ['suricata.service']


class JournalMonitor(object):

    def __init__(self):
        self.journal = journal.Reader()
        for unit in UNITS:
            self.journal.add_match(_SYSTEMD_UNIT=unit)
        self.journal.seek_tail()
        self.journal.get_previous()
        reactor.addReader(self)

    def fileno(self):
        return self.journal.fileno()

    def doRead(self):
        if self.journal.process() != journal.APPEND:
            return
        for entry in self.journal:
            print(entry)

    def connectionLost(self, reason):
        print(reason)
        if reactor.running:
            reactor.stop()

    def logPrefix(self):
        return self.__class__.__name__


JournalMonitor()
reactor.run()