:mod:`syslog` --- Unix syslog library routines ============================================== .. module:: syslog :platform: Unix :synopsis: An interface to the Unix syslog library routines. -------------- This module provides an interface to the Unix ``syslog`` library routines. Refer to the Unix manual pages for a detailed description of the ``syslog`` facility. .. availability:: Unix, not Emscripten, not WASI. This module wraps the system ``syslog`` family of routines. A pure Python library that can speak to a syslog server is available in the :mod:`logging.handlers` module as :class:`~logging.handlers.SysLogHandler`. The module defines the following functions: .. function:: syslog(message) syslog(priority, message) Send the string *message* to the system logger. A trailing newline is added if necessary. Each message is tagged with a priority composed of a *facility* and a *level*. The optional *priority* argument, which defaults to :const:`LOG_INFO`, determines the message priority. If the facility is not encoded in *priority* using logical-or (``LOG_INFO | LOG_USER``), the value given in the :func:`openlog` call is used. If :func:`openlog` has not been called prior to the call to :func:`syslog`, :func:`openlog` will be called with no arguments. .. audit-event:: syslog.syslog priority,message syslog.syslog .. versionchanged:: 3.2 In previous versions, :func:`openlog` would not be called automatically if it wasn't called prior to the call to :func:`syslog`, deferring to the syslog implementation to call ``openlog()``. .. versionchanged:: 3.12 This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) :func:`openlog` must be called in the main interpreter before :func:`syslog` may be used in a subinterpreter. Otherwise it will raise :exc:`RuntimeError`. .. function:: openlog([ident[, logoption[, facility]]]) Logging options of subsequent :func:`syslog` calls can be set by calling :func:`openlog`. :func:`syslog` will call :func:`openlog` with no arguments if the log is not currently open. The optional *ident* keyword argument is a string which is prepended to every message, and defaults to ``sys.argv[0]`` with leading path components stripped. The optional *logoption* keyword argument (default is 0) is a bit field -- see below for possible values to combine. The optional *facility* keyword argument (default is :const:`LOG_USER`) sets the default facility for messages which do not have a facility explicitly encoded. .. audit-event:: syslog.openlog ident,logoption,facility syslog.openlog .. versionchanged:: 3.2 In previous versions, keyword arguments were not allowed, and *ident* was required. .. versionchanged:: 3.12 This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) This may only be called in the main interpreter. It will raise :exc:`RuntimeError` if called in a subinterpreter. .. function:: closelog() Reset the syslog module values and call the system library ``closelog()``. This causes the module to behave as it does when initially imported. For example, :func:`openlog` will be called on the first :func:`syslog` call (if :func:`openlog` hasn't already been called), and *ident* and other :func:`openlog` parameters are reset to defaults. .. audit-event:: syslog.closelog "" syslog.closelog .. versionchanged:: 3.12 This function is restricted in subinterpreters. (Only code that runs in multiple interpreters is affected and the restriction is not relevant for most users.) This may only be called in the main interpreter. It will raise :exc:`RuntimeError` if called in a subinterpreter. .. function:: setlogmask(maskpri) Set the priority mask to *maskpri* and return the previous mask value. Calls to :func:`syslog` with a priority level not set in *maskpri* are ignored. The default is to log all priorities. The function ``LOG_MASK(pri)`` calculates the mask for the individual priority *pri*. The function ``LOG_UPTO(pri)`` calculates the mask for all priorities up to and including *pri*. .. audit-event:: syslog.setlogmask maskpri syslog.setlogmask The module defines the following constants: .. data:: LOG_EMERG LOG_ALERT LOG_CRIT LOG_ERR LOG_WARNING LOG_NOTICE LOG_INFO LOG_DEBUG Priority levels (high to low). .. data:: LOG_AUTH LOG_AUTHPRIV LOG_CRON LOG_DAEMON LOG_FTP LOG_INSTALL LOG_KERN LOG_LAUNCHD LOG_LPR LOG_MAIL LOG_NETINFO LOG_NEWS LOG_RAS LOG_REMOTEAUTH LOG_SYSLOG LOG_USER LOG_UUCP LOG_LOCAL0 LOG_LOCAL1 LOG_LOCAL2 LOG_LOCAL3 LOG_LOCAL4 LOG_LOCAL5 LOG_LOCAL6 LOG_LOCAL7 Facilities, depending on availability in ```` for :const:`LOG_AUTHPRIV`, :const:`LOG_FTP`, :const:`LOG_NETINFO`, :const:`LOG_REMOTEAUTH`, :const:`LOG_INSTALL` and :const:`LOG_RAS`. .. versionchanged:: 3.13 Added :const:`LOG_FTP`, :const:`LOG_NETINFO`, :const:`LOG_REMOTEAUTH`, :const:`LOG_INSTALL`, :const:`LOG_RAS`, and :const:`LOG_LAUNCHD`. .. data:: LOG_PID LOG_CONS LOG_NDELAY LOG_ODELAY LOG_NOWAIT LOG_PERROR Log options, depending on availability in ```` for :const:`LOG_ODELAY`, :const:`LOG_NOWAIT` and :const:`LOG_PERROR`. Examples -------- Simple example ~~~~~~~~~~~~~~ A simple set of examples:: import syslog syslog.syslog('Processing started') if error: syslog.syslog(syslog.LOG_ERR, 'Processing started') An example of setting some log options, these would include the process ID in logged messages, and write the messages to the destination facility used for mail logging:: syslog.openlog(logoption=syslog.LOG_PID, facility=syslog.LOG_MAIL) syslog.syslog('E-mail processing initiated...')