ZConfig.components.logger package provides configuration
support for the
logging package in Python’s standard library.
This component can be imported using:
This component defines two abstract types and several concrete section types. These can be imported as a unit, as above, or as four smaller components usable in creating alternate logging packages.
The first of the four smaller components contains the abstract types, and can be imported using:
<import package="ZConfig.components.logger" file="abstract.xml"/>
The two abstract types imported by this are:
- Logger objects are represented by this abstract type.
- Each logger object can have one or more “handlers” associated with
them. These handlers are responsible for writing logging events to
some form of output stream using appropriate formatting. The output
stream may be a file on a disk, a socket communicating with a server
on another system, or a series of
syslogmessages. Section types which implement this type represent these handlers.
The second and third of the smaller components provides section types
that act as factories for
logging.Logger objects. These can be
<import package="ZConfig.components.logger" file="eventlog.xml"/> <import package="ZConfig.components.logger" file="logger.xml"/>
The types defined in these components implement the
ZConfig.logger.log abstract type. The ‘eventlog.xml’
component defines an eventlog type which represents the
root logger from the the
logging package (the return value of
logging.getLogger()), while the ‘logger.xml’ component
defines a logger section type which represents a named
The third of the smaller components provides section types that are
logging.Handler objects. This can be imported
<import package="ZConfig.components.logger" file="handlers.xml"/>
The types defined in this component implement the ZConfig.logger.handler abstract type.
The configuration objects provided by both the logger and handler types are factories for the finished loggers and handlers. These factories should be called with no arguments to retrieve the logger or log handler objects. Calling the factories repeatedly will cause the same objects to be returned each time, so it’s safe to simply call them to retrieve the objects.
The factories for the logger objects, whether the eventlog
or logger section type is used, provide a
method which may be called to close any log files and re-open them.
This is useful when using a UNIX signal to effect log file
rotation: the signal handler can call this method, and not have to
worry about what handlers have been registered for the logger. There
is also a function in the
ZConfig.components.logger.loghandler module that re-opens all
open log files created using ZConfig configuration:
Closes and re-opens all the log files held open by handlers created by the factories for
logfilesections. This is intended to help support log rotation for applications.
Using The Logging Components¶
Building an application that uses the logging components is fairly straightforward. The schema needs to import the relevant components and declare their use:
<schema> <import package="ZConfig.components.logger" file="eventlog.xml"/> <import package="ZConfig.components.logger" file="handlers.xml"/> <section type="eventlog" name="*" attribute="eventlog" required="yes"/> </schema>
In the application, the schema and configuration file should be loaded
normally. Once the configuration object is available, the logger
factory should be called to configure Python’s
import os import ZConfig def run(configfile): schemafile = os.path.join(os.path.dirname(__file__), "schema.xml") schema = ZConfig.loadSchema(schemafile) config, handlers = ZConfig.loadConfig(schema, configfile) # configure the logging package: config.eventlog() # now do interesting things
An example configuration file for this application may look like this:
<eventlog> level info <logfile> path /var/log/myapp format %(asctime)s %(levelname)s %(name)s %(message)s # locale-specific date/time representation dateformat %c </logfile> <syslog> level error address syslog.example.net:514 format %(levelname)s %(name)s %(message)s </syslog> </eventlog>
Refer to the
logging.LogRecord documentation for the names
available in the message format strings (the
format key in the
log handlers). The date format strings (the
dateformat key in
the log handlers) are the same as those accepted by the