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""" |
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syslog2irc.syslog |
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~~~~~~~~~~~~~~~~~ |
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BSD syslog message reception and handling |
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:Copyright: 2007-2021 Jochen Kupperschmidt |
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:License: MIT, see LICENSE for details. |
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""" |
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from functools import partial |
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import logging |
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from socketserver import BaseRequestHandler, ThreadingUDPServer |
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import sys |
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from typing import Iterable |
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import syslogmp |
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from syslogmp import Message as SyslogMessage |
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from .signals import syslog_message_received |
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from .util import start_thread |
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logger = logging.getLogger(__name__) |
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class RequestHandler(BaseRequestHandler): |
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"""Handler for syslog messages.""" |
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def __init__(self, port: int, *args, **kwargs) -> None: |
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self.port = port |
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super().__init__(*args, **kwargs) |
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def handle(self) -> None: |
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try: |
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data = self.request[0] |
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message = syslogmp.parse(data) |
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except ValueError: |
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logger.info( |
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'Invalid message received from %s:%d.', *self.client_address |
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) |
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return None |
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logger.debug( |
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'Received message from %s:%d on port %d -> %s', |
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self.client_address[0], |
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self.client_address[1], |
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self.port, |
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format_message_for_log(message), |
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) |
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syslog_message_received.send( |
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self.port, source_address=self.client_address, message=message |
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) |
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def create_server(port: int) -> ThreadingUDPServer: |
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"""Create a threading UDP server to receive syslog messages.""" |
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address = ('', port) |
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handler_class = partial(RequestHandler, port) |
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return ThreadingUDPServer(address, handler_class) |
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def start_server(port: int) -> None: |
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"""Start a server, in a separate thread.""" |
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try: |
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server = create_server(port) |
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except OSError as e: |
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sys.stderr.write(f'Error {e.errno:d}: {e.strerror}\n') |
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sys.stderr.write( |
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f'Probably no permission to open port {port:d}. ' |
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'Try to specify a port number above 1,024 (or even ' |
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'4,096) and up to 65,535.\n' |
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) |
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sys.exit(1) |
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thread_name = f'{server.__class__.__name__}-port{port:d}' |
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start_thread(server.serve_forever, thread_name) |
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logger.info( |
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'Listening for syslog messages on %s:%d.', *server.server_address |
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) |
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def start_syslog_message_receivers(ports: Iterable[int]) -> None: |
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"""Start one syslog message receiving server for each port.""" |
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for port in ports: |
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start_server(port) |
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def format_message_for_log(message: SyslogMessage) -> str: |
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"""Format a syslog message to be logged.""" |
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facility_name = message.facility.name |
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severity_name = message.severity.name |
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timestamp_str = message.timestamp.isoformat() |
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hostname = message.hostname |
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return ( |
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f'facility={facility_name}, ' |
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f'severity={severity_name}, ' |
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f'timestamp={timestamp_str}, ' |
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f'hostname={hostname}, ' |
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f'message={message.message}' |
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) |
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