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Revision as of 20:28, 19 January 2013 by Lmacken (talk | contribs) (Best Practices for Fedora Infrastructure Apps)

Best Practices for Fedora Infrastructure Apps

Coding style

Centralized logging

Most of our apps use the standard Python logging module, which usually ends up logging to /var/log/httpd/error_log on the app server.

To have your app logs shipped to our central logging server, you can configure the SysLogHandler to do so.

For config-file based logging setups, you can do something like the following:

[logging]                                                                                                                                                             
                                                                                                                                                                          
[[handlers]]                                                                                                                                                          
                                                                                                                                                                         
[[[syslog_out]]]                                                                                                                                                      
class='handlers.SysLogHandler'                                                                                                                                        
args="('/dev/log', handlers.SysLogHandler.LOG_LOCAL4,)"                                                                                                               
formatter='message_only'                                                                                                                                              
                                                                                                                                                                          
[[loggers]]                                                                                                                                                           
                                                                                                                                                                          
[[[bodhi]]]                                                                                                                                                           
level='DEBUG'                                                                                                                                                         
qualname='bodhi'                                                                                                                                                      
handlers=['syslog_out']                                                                                                                                               
propagate=0                                                                                                                                                           

Here is an example of doing it in pure Python:

import logging
import logging.handlers

syslogger = logging.getLogger('bodhi')
syslogger.setLevel(logging.DEBUG)
handler = logging.handlers.SysLogHandler(address='/dev/log', facility=logging.handlers.SysLogHandler.LOG_LOCAL4)
syslogger.addHandler(handler)
syslogger.info('Hello SysLog!')

The app logs will then appear in /var/log/hosts/<HOST>/<YEAR>/<MONTH>/<DAY>/apps.log as well as the merged log /var/log/merged/apps.log.