'''
To use the per application log file with rotating file handler in
web2py you need to put this file (log.py) into your models folder. The log
file itself is created in your_web2py_path/applications/
your_application/app.log

Writing into the log file from your controller works as follows:
def my_function():
    logging.debug('my function abc is starting')
    logging.error('huston we got a %s problem.' % 'major')
    return

Viewing the log file through your application works as follows:
def show_log():
    return get_log()

If required the GAE solution needs work.
A BIG thank you to Iceberg!
Feedback and usage is welcome ;-) 

Important note: do *not* 'import logging' in your controller if you
use log.py. its done for all your controllers already in the log.py
model and it would break the log.py magic. 
'''

import logging 

def _init_log(level=logging.DEBUG,formatter="%(asctime)s %(levelname)s %(funcName)s():%(lineno)d %(message)s",filename='app.log',maxBytes=1024*1024,backupCount=2): 
    import os,logging.handlers 
    logger=logging.getLogger(request.application) 
    logger.setLevel(level) 
    if request.env.web2py_runtime_gae: # if running on Google App Engine 
        handler=logging.handlers.HTTPHandler(request.env.http_host,URL(r=request,f='log')) # assuming there is an optional log action 
    else: 
        handler=logging.handlers.RotatingFileHandler(os.path.join(request.folder,filename),maxBytes=maxBytes,backupCount=backupCount)
    handler.setLevel(level)
    handler.setFormatter(logging.Formatter(formatter)) 
    logger.addHandler(handler)
    logger.debug("web2py application %s starting" % request.application)
    return logger 

def get_log():
    try:
        f = open(logging.handlers[0].baseFilename, 'r')
        c = f.readlines()
        f.close()
        return {'log':TABLE(*[TR(str(item)) for item in c])}
    except:
        return ()
    
logging=cache.ram('mylog',lambda:_init_log(),time_expire=99999999)