RELP server/client for python

install

• pip install relppy

example

server

import socketserver
from relppy.server import RelpStreamHandler
from relppy.protocol import Message


class MyHandler(RelpStreamHandler):
    def do_syslog(self, msg: Message):
        print(msg.data.decode("ascii"))


if __name__ == "__main__":
    srv = socketserver.TCPServer(("localhost", 10514), MyHandler)
    srv.serve_forever()

client

from relppy.client import RelpTCPClient

with RelpTCPClient(("localhost", 10514)) as cl:
    for m in ["hello", "world"]:
        fut= cl.send_command(b"syslog", m.encode())
        res = fut.result()
        print(f"sent: {m} -> {res}")

log handler

relppy comes with a logging handler that can be used with python logging. The handler has four special arguments.

spool_method=<function>

You can specify a spool method. This method is called with the log record instance as argument if the record could not be sent (e.g. relp log server down) to spool it for later resend. Writing the spool/resend methods is up to the developer.

exception_on_emit=<bool>

If exception_on_emit is True, the emit() method of the log handler raises an exception if the log message could not be sent. This results in an exception (e.g. Connection refused) when calling the logger (e.g. logger.info). This behavior is intended to be used in the resend method (see spool_method above) to ensure all spooled messages are delivered to the relp log server.

logger=<logging.Logger>

The logger instance that is used to log connection failures.

active_log_handlers=<List>

A list that the log handler is added to on init and removed from on close(). This is useful in multiprocessing programs/daemons to close all open loggers on exit.

Examples

import logging
from relppy.log_handler import RelpHandler

log_handler = RelpHandler(address=(server, port), facility="LOCAL7")

formatter = logging.Formatter('%(name)s: [%(levelname)s] %(message)s')
log_handler.setFormatter(formatter)
logger = logging.getLogger("my_logger")
logger.addHandler(log_handler)

Passing a SSL context enables TLS.

import ssl
import logging
from relppy.log_handler import RelpHandler

context = ssl.create_default_context(
    purpose=ssl.Purpose.SERVER_AUTH,
    cafile="/path/to/ca.cert",
)
context.load_cert_chain(certfile="/path/to/client-cert.pem",
                        keyfile="/path/to/client-key.pem")

log_handler = RelpHandler(address=(server, port),
                        facility="LOCAL7",
                        context=context)

formatter = logging.Formatter('%(name)s: [%(levelname)s] %(message)s')
log_handler.setFormatter(formatter)

logger = logging.getLogger("my_logger")
logger.addHandler(log_handler)

CLI command

relppy comes with a CLI command to send messages to a relp server rsyslog example.

relppy logger --logger-name audit-log --host servername --port port --log-level INFO --priority info --facility LOCAL7 "Test message"

relppy logger-tls --logger-name audit-log --host servername --port port --cafile /path/to/syslog-ca.pem --certfile /path/to/syslog-cert.pem --keyfile /path/to/syslog-key.pem --log-level INFO --priority info --facility LOCAL7 "Test message via TLS"