Syslog Handler

Send log messages to syslog with proper RFC 5424 severity mapping.

Basic Usage

No additional installation required - uses Python’s built-in syslog support.

from richcolorlog import setup_logging

logger = setup_logging(
    syslog=True,
    syslog_host='localhost',
    syslog_port=514,
)

logger.info("This goes to syslog!")

Configuration Parameters

Parameter	Default	Description
`syslog`	`False`	Enable syslog handler
`syslog_host`	`'localhost'`	Syslog server hostname
`syslog_port`	`514`	Syslog server port
`syslog_facility`	`LOG_USER`	Syslog facility code
`syslog_level`	`DEBUG`	Minimum level for syslog

Severity Mapping

RichColorLog maps levels to RFC 5424 severities:

RichColorLog Level	Severity	Description
EMERGENCY (60)	0	System is unusable
ALERT (59)	1	Action must be taken immediately
FATAL (55)	1	Fatal error (maps to Alert)
CRITICAL (58, 50)	2	Critical conditions
ERROR (40)	3	Error conditions
WARNING (30)	4	Warning conditions
NOTICE (25)	5	Normal but significant
INFO (20)	6	Informational messages
DEBUG (10)	7	Debug-level messages

Syslog Facilities

Common facilities:

import logging.handlers as handlers

logger = setup_logging(
    syslog=True,
    syslog_facility=handlers.SysLogHandler.LOG_USER,      # Default
)

# Other facilities
handlers.SysLogHandler.LOG_LOCAL0  # Local use 0
handlers.SysLogHandler.LOG_LOCAL1  # Local use 1
handlers.SysLogHandler.LOG_LOCAL2  # Local use 2
handlers.SysLogHandler.LOG_LOCAL3  # Local use 3
handlers.SysLogHandler.LOG_LOCAL4  # Local use 4
handlers.SysLogHandler.LOG_LOCAL5  # Local use 5
handlers.SysLogHandler.LOG_LOCAL6  # Local use 6
handlers.SysLogHandler.LOG_LOCAL7  # Local use 7
handlers.SysLogHandler.LOG_DAEMON  # System daemons
handlers.SysLogHandler.LOG_AUTH    # Security/auth

Message Format

Default format:

myapp[12345]: INFO - User logged in

Customize with formatter:

import logging
from richcolorlog import setup_logging

logger = setup_logging(syslog=True)

# Find and update syslog handler
for handler in logger.handlers:
    if isinstance(handler, logging.handlers.SysLogHandler):
        handler.setFormatter(logging.Formatter(
            '%(name)s: %(levelname)s %(message)s'
        ))

Local Syslog (Unix Socket)

For local syslog on Unix systems:

import logging.handlers

# Use Unix socket instead of network
handler = logging.handlers.SysLogHandler(
    address='/dev/log',  # Linux
    # address='/var/run/syslog',  # macOS
    facility=logging.handlers.SysLogHandler.LOG_USER
)

logger = logging.getLogger('myapp')
logger.addHandler(handler)

Remote Syslog Server

Send to a remote syslog server:

logger = setup_logging(
    syslog=True,
    syslog_host='syslog.example.com',
    syslog_port=514,
)

For TLS-encrypted syslog, use a dedicated library like syslog-rfc5424-formatter.

rsyslog Configuration

Configure rsyslog to receive logs:

# /etc/rsyslog.conf

# Enable UDP
module(load="imudp")
input(type="imudp" port="514")

# Route by facility
local0.*    /var/log/myapp.log

systemd-journald

On systemd systems, logs can go to journald:

import logging
from systemd.journal import JournalHandler

logger = logging.getLogger('myapp')
logger.addHandler(JournalHandler())

# Works with richcolorlog too
from richcolorlog import setup_logging
logger = setup_logging()
logger.addHandler(JournalHandler())

Production Configuration

import logging.handlers

logger = setup_logging(
    name='production_app',
    level='INFO',

    syslog=True,
    syslog_host='syslog.example.com',
    syslog_port=514,
    syslog_facility=logging.handlers.SysLogHandler.LOG_LOCAL0,
    syslog_level='WARNING',  # Only warnings and above to syslog
)

Viewing Syslog

# Linux
tail -f /var/log/syslog
journalctl -f

# macOS
log stream --predicate 'process == "python"'

# Filter by facility
tail -f /var/log/local0.log

Direct Handler Usage

import logging
from richcolorlog.logger import SyslogHandler

handler = SyslogHandler(
    host='localhost',
    port=514,
    facility=logging.handlers.SysLogHandler.LOG_LOCAL0,
    level=logging.WARNING
)

logger = logging.getLogger('myapp')
logger.addHandler(handler)