RedisLogHandler.py

class RedisLogHandler(Process):
    """
    Single point to collect logs through redis pub/sub and write
        them through standard python logging lib
    """

    def __init__(self, opts):
        Process.__init__(self, name="log_handler")

        self.opts = opts

        self.log_dir = os.path.dirname(self.opts.log_dir)
        if not os.path.exists(self.log_dir):
            os.makedirs(self.log_dir, mode=0o750)

        self.components = ["spawner", "terminator",
                           "vmm", "job_grab", "backend"]

    def setup_logging(self):
        formatter = logging.Formatter(
            '[%(asctime)s][%(levelname)6s][%(name)10s][%(pathname)s:%(funcName)s:%(lineno)d] %(message)s')

        self.main_logger = logging.Logger("logger", level=logging.DEBUG)
        self.main_handler = logging.handlers.WatchedFileHandler(
            filename=os.path.join(self.log_dir, "logger.log"))
        self.main_handler.setFormatter(formatter)
        self.main_logger.addHandler(self.main_handler)

        self.router_logger = logging.Logger("log_router")
        self.router_logger.addFilter(CustomFilter())

        for component in self.components:
            handler = logging.handlers.WatchedFileHandler(
                filename=os.path.join(self.log_dir, "{}.log".format(component)))
            handler.setFormatter(formatter)

            # not very good from performance point:
            #   filter called for each message, but only one handler process record
            # but it shouldn't be a real problem
            handler.addFilter(filter=LogRouterFilter(component))
            self.router_logger.addHandler(handler)

    def handle_msg(self, raw):
        try:
            event = json.loads(raw["data"])

            # expected fields:
            #   - who: self.components
            #   - level: "info", "debug", "error", None --> default is "info"
            #   - msg: str with log msg
            #   [- traceback: str with error traceback ]
            #   [ more LogRecord kwargs, see: https://docs.python.org/2/library/logging.html#logrecord-objects]

            for key in ["who", "msg"]:
                if key not in event:
                    raise Exception("Handler received msg without `{}` field, msg: {}".format(key, event))

            who = event["who"]
            if who not in self.components:
                raise Exception("Handler received msg with unknown `who` field, msg: {}".format(event))

            level = level_map[event.pop("level", "info")]
            msg = event.pop("msg")

            self.router_logger.log(level, msg, extra={"event": event})

        except Exception as err:
            self.main_logger.exception(err)

    def run(self):
        self.setup_logging()
        setproctitle("RedisLogHandler")

        rc = helpers.get_redis_connection(self.opts)
        channel = rc.pubsub(ignore_subscribe_messages=True)
        channel.subscribe(constants.LOG_PUB_SUB)

        for raw in channel.listen():
            if raw is not None and raw.get("type") == "message" and "data" in raw:
                self.handle_msg(raw)