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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 ( |
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BaseRequestHandler, |
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StreamRequestHandler, |
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ThreadingTCPServer, |
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ThreadingUDPServer, |
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) |
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import sys |
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from typing import Iterable, Tuple, Union |
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import syslogmp |
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from syslogmp import Message as SyslogMessage |
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from .network import format_port, Port, TransportProtocol |
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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 TCPHandler(StreamRequestHandler): |
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"""Handler for syslog messages arriving via TCP.""" |
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def __init__(self, port: Port, *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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for line in self.rfile: |
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try: |
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message = syslogmp.parse(line) |
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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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_handle_received_message(self.client_address, self.port, message) |
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class UDPHandler(BaseRequestHandler): |
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"""Handler for syslog messages arriving via UDP.""" |
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def __init__(self, port: Port, *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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_handle_received_message(self.client_address, self.port, message) |
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def _handle_received_message( |
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client_address: Tuple[str, int], port: Port, message: SyslogMessage |
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) -> None: |
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logger.debug( |
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'Received message from %s:%d on port %s -> %s', |
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client_address[0], |
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client_address[1], |
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format_port(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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port, source_address=client_address, message=message |
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) |
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def create_server(port: Port) -> Union[ThreadingTCPServer, ThreadingUDPServer]: |
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"""Create a threading server to receive syslog messages.""" |
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address = ('', port.number) |
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if port.transport_protocol == TransportProtocol.TCP: |
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tcp_handler_class = partial(TCPHandler, port) |
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return ThreadingTCPServer(address, tcp_handler_class) |
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elif port.transport_protocol == TransportProtocol.UDP: |
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udp_handler_class = partial(UDPHandler, port) |
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return ThreadingUDPServer(address, udp_handler_class) |
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else: |
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raise ValueError(f'Unsupported transport protocol') |
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def start_server(port: Port) -> 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'Cannot open port {format_port(port)}. Could be already in use. ' |
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f'Or permission is lacking; try a port number above 1,024 (or ' |
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'even 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}' |
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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:%s.', |
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server.server_address[0], |
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format_port(port), |
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) |
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def start_syslog_message_receivers(ports: Iterable[Port]) -> 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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1 |
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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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return ( |
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f'facility={message.facility.name}, ' |
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f'severity={message.severity.name}, ' |
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f'timestamp={message.timestamp.isoformat()}, ' |
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f'hostname={message.hostname}, ' |
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f'message={message.message}' |
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) |
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homeworkprod /
syslog2irc
