Towards simple settings for logging

settings_a1.py

## Example settings wodge for standard configuration

LOGGING_CONFIG = 'nlm.occs.logging.configure_logging'

# The above compiles to our current "standard" wodge, except:
#  - all "local" apps become installed apps
#  - the level for "local" apps becomes automatically either 'DEBUG' if settings.DEBUG else 'INFO'

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'full': {
            'format': '[%(asctime)s] %(levelname)s %(name)s %(message)s',
        },
    },
    'filters': {
        'require_debug_true_or_tty': {
            '()': 'nlm.occs.logging.DebugTrueOrTTYFilter',
        },
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse',
        },
       'skip_nessus_scan_requests': {
            '()': 'nlm.occs.logging.SkipNessusScanFilter',
        }
    },
    'handlers': {
        'file': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'encoding': 'UTF-8',
            'filename': os.path.join(os.environ.get('LOG_DIR', 'logs'), 'occsdjango.log'),
        },
        'console': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.StreamHandler',
            'filters': ['require_debug_true_or_tty'],
        },
        'mail_admins': {
            'level': 'ERROR',
            'filters': ['require_debug_false', 'skip_nessus_scan_requests'],
            'class': 'django.utils.log.AdminEmailHandler',
            'include_html': True,
        },
    },
    'loggers': {
        'nlm.occs': {
            'handlers': ['file'],
            'level': 'INFO',
            'propagate': True,
        },
        'django': {
            'handlers': ['file', 'console'],
            'level': 'INFO',
            'propagate': True,
        },
        # NOTE: All local apps are added by LOGGING_CONFIG above, and their level is set based 
        # on settings.DEBUG to 'DEBUG' or 'INFO' automatically.
    },
}

settings_a1_strict.py

## nlm.occs.logging.configure_logging only accepts the following keys in LOGGING
#       logdir
#       filename
#       full_format
#       debug_sql
#       mail_admins
#       extra_loggers
# 
# So, the following will raise ImproperlyConfigured with a helpful messsage
#

LOGGING_CONFIG = 'nlm.occs.logging.configure_logging'

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'full': {
            'format': '[%(asctime)s] %(levelname)s %(name)s %(message)s',
        },
    },
    'filters': {
        'require_debug_true_or_tty': {
            '()': 'infrastructure.log.DebugTrueOrTTYFilter',
        },
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse',
        },
        'skip_nessus_scan_requests': {
            '()': 'infrastructure.log.SkipNessusScanFilter',
        }
    },
    'handlers': {
        'file': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'encoding': 'UTF-8',
            'filename': os.path.join(LOG_DIR, LOG_FILENAME),
        },
        'console': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.StreamHandler',
            'filters': ['require_debug_true_or_tty'],
        },
        'mail_admins': {
            'level': 'ERROR',
            'filters': ['require_debug_false', 'skip_nessus_scan_requests'],
            'class': 'django.utils.log.AdminEmailHandler',
            'include_html': True,
        },
    },
    'loggers': {
        'nlm.occs': {
            'handlers': ['file' ],
            'level': 'INFO',
            'propagate': True,
        },
        'django': {
            'handlers': ['file', 'console'],
            'level': 'INFO',
            'propagate': True,
        },
        'cfmedicine': {
            'handlers': ['file', 'console'],
            'level': 'INFO',
            'propagate': True,
        }
    },
}

##

settings_a2.py

## Example settings wodge to explain what things do:

LOGGING_CONFIG = 'nlm.occs.logging.configure_logging'

LOGGING = {
    'full_format': '[%(asctime)s] %(levelname)s %(name)s %(message)s',   # Override the format used for file and stream above
    'logdir': ....,                                                      # self-explanatory, overrides DJANGO_LOG_DIR
    'filename': ....,                                                    # changes log-name from standard "occsdjango.log'
    'mail_admins': True,                                                 # Changes the wodge to what is below
}

# This translates a bit differently:

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'full': {
            'format': full_format,                                       # Argument passed through LOGGING = 
        },
    },
    'filters': {
        'require_debug_true_or_tty': {
            '()': 'nlm.occs.logging.DebugTrueOrTTYFilter',
        },
        'require_debug_false': {
            '()': 'django.utils.log.RequireDebugFalse',
        },
       'skip_nessus_scan_requests': {
            '()': 'nlm.occs.logging.SkipNessusScanFilter',
        }
    },
    'handlers': {
        'file': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'encoding': 'UTF-8',
            'filename': os.path.join(logdir, filename),
        },
        'console': {
            'formatter': 'full',
            'level': 'DEBUG',
            'class': 'logging.StreamHandler',
            'filters': ['require_debug_true_or_tty'],
        },
        'mail_admins': {
            'level': 'ERROR',
            'filters': ['require_debug_false', 'skip_nessus_scan_requests'],
            'class': 'django.utils.log.AdminEmailHandler',
            'include_html': True,
        },
    },
    'loggers': {
        'nlm.occs': {
            'handlers': ['file', 'mail_admins'],                    # Because of argument mail_admins True
            'level': 'INFO',
            'propagate': True,
        },
        'django': {
            'handlers': ['file', 'console', 'mail_admins'],         # Because of argument mail_admins True
            'level': 'INFO',
            'propagate': True,
        },
        # NOTE: All local apps are added by LOGGING_CONFIG above
    },
}

settings_a3.py

## extra_loggers may be passed through, and debug_sql is also supported

LOGGING_CONFIG = 'nlm.occs.logging.configure_logging'

LOGGING = {
    'debug_sql': True,
    # These are added to the configuration
    'extra_loggers': {
        'django_cas_ng': {
            'handlers': ['console'],
            'level': 'DEBUG',
            'propagate': True,           
        },
        'cas': {
            'handlers': ['console'],
            'level': 'DEBUG',
        }
    }
}

settings_b_simple.py

## 
# Here, we still have nlm.occs.logging.configure_logging, but rather than attempt to discover locally installed apps,
# we instead assume that all local logging is done under 'nlm.occs.app', and provide a helper.  So, the job of the code
# is simpler

LOGGING_CONFIG = 'nlm.occs.logging.configure_logging'

# Translation does not include local apps, because users are expected to get a logger like this:

from nlm.occs.logging import getLogger

logger = getLogger(__name__)

# The implementation is simple

def getLoggir(name=None):
    return logging.getLogger('nlm.occs.app.%s' % name if name else 'nlm.occs.app')
     
# The user can just log from 'nlm.occs.app', and it works, but if he/she wants to know where it came from, that works too.

# And so the logging wodge is translated without trying to find local apps.   The code to build this is not so hard, right:

    try:
        config = LoggingConfig(**logging_settings)  
    except:
        raise ImproperlyConfigured(...)
        
    # This *is* more complicated because of config.debug_sql, etc.
    loggers = {
        'nlm.occs': {
            'handlers': ['file'],
            'level': 'INFO',
            'propagate': True,
        },
        'django': {
            'handlers': ['file', 'console'],
            'level': 'INFO',
            'propagate': True,
        }
    }
    # This part isn't complicated
    loggers.update(logging_config.extra_loggers)
    
    realdict = {
        'version': 1,
        'disable_existing_loggers': False,
        'formatters': {
            'full': {
                'format': config.full_format,
            },
        },
        'filters': {
            'require_debug_true_or_tty': {
                '()': 'nlm.occs.logging.DebugTrueOrTTYFilter',
            },
            'require_debug_false': {
                '()': 'django.utils.log.RequireDebugFalse',
            },
           'skip_nessus_scan_requests': {
                '()': 'nlm.occs.logging.SkipNessusScanFilter',
            }
        },
        'handlers': {
            'file': {
                'formatter': 'full',
                'level': 'DEBUG',
                'class': 'logging.FileHandler',
                'encoding': 'UTF-8',
                'filename': config.log_file_path,
            },
            'console': {
                'formatter': 'full',
                'level': 'DEBUG',
                'class': 'logging.StreamHandler',
                'filters': ['require_debug_true_or_tty'],
            },
            'mail_admins': {
                'level': 'ERROR',
                'filters': ['require_debug_false', 'skip_nessus_scan_requests'],
                'class': 'django.utils.log.AdminEmailHandler',
                'include_html': True,
            },
        },
        'loggers': loggers,
    }
    logging.dictConfig(realdict)