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'''WSGI logging and event reporting middleware.''' import pdb import sys import logging from cgitb import html from logging.handlers import HTTPHandler, SysLogHandler from logging.handlers import TimedRotatingFileHandler, SMTPHandler __all__ = ['WsgiLog', 'log'] # File rotation constants BACKUPS = 1 INTERVAL = 'h' SPACING = 1 # Default logger name (should be changed) LOGNAME = 'wsgilog.log' # Default 'environ' entries CATCHID = 'wsgilog.catch' LOGGERID = 'wsgilog.logger' # Current proposed 'environ' key signalling no middleware exception handling THROWERR = 'x-wsgiorg.throw_errors' # HTTP error messages HTTPMSG = '500 Internal Error' ERRORMSG = 'Server got itself in trouble' # Default log formats DATEFORMAT = '%a, %d %b %Y %H:%M:%S' LOGFORMAT = '%(name)s: %(asctime)s %(levelname)-4s %(message)s' def _errapp(environ, start_response): '''Default error handling WSGI application.''' start_response(HTTPMSG, [('Content-type', 'text/plain')], sys.exc_info()) return [ERRORMSG] def log(**kw): '''Decorator for logging middleware.''' def decorator(application): return WsgiLog(application, **kw) return decorator class LogStdout(object): '''File-like object for sending stdout output to a logger.''' def __init__(self, logger, level=logging.DEBUG): # Set logger level if level == logging.DEBUG: self.logger = logger.debug elif level == logging.CRITICAL: self.logger = logger.critical elif level == logging.ERROR: self.logger = logger.warning elif level == logging.WARNING: self.logger = logger.warning elif level == logging.INFO: self.logger = logger.info def write(self, info): '''Writes non-whitespace strings to logger.''' if info.lstrip().rstrip() != '': self.logger(info) class WsgiLog(object): '''Class for WSGI logging and event recording middleware.''' def __init__(self, application, **kw): self.application = application # Error handling WSGI app self._errapp = kw.get('errapp', _errapp) # Flag controlling logging self.log = kw.get('log', True) # Log if set if self.log: # Log error message self.message = kw.get('logmessage', ERRORMSG) # Individual logger for WSGI app with custom name 'logname' self.logger = logging.getLogger(kw.get('logname', LOGNAME)) # Set logger level self.logger.setLevel(kw.get('loglevel', logging.DEBUG)) # Coroutine for setting individual log handlers def setlog(logger): logger.setFormatter(logging.Formatter( # Log entry format kw.get('logformat', LOGFORMAT), # Date format kw.get('datefmt', DATEFORMAT) )) self.logger.addHandler(logger) # Log to STDOUT if 'tostream' in kw: setlog(logging.StreamHandler()) # Log to a rotating file that with periodic backup deletions if 'tofile' in kw: setlog(TimedRotatingFileHandler( # Log file path kw.get('file', LOGNAME), # Interval to backup log file kw.get('interval', INTERVAL), # pacing between interval units kw.get('spacing', SPACING), # Number of backups to keep kw.get('backups', BACKUPS) )) # Send log entries to an email address if 'toemail' in kw: setlog(SMTPHandler( # Mail server kw.get('mailserver'), # From email address kw.get('frommail'), # To email address kw.get('toemail'), # Email subject kw.get('mailsubject') )) # Send log entries to a web server if 'tohttp' in kw: setlog(HTTPHandler( # Web server host kw.get('httphost'), # Web URL kw.get('httpurl'), # HTTP method kw.get('httpmethod', 'GET') )) # Log to syslog if 'tosyslog' in kw: setlog(SysLogHandler( # syslog host kw.get('syshost', ('localhost', 514)), # syslog user kw.get('facility', 'LOG_USER') )) assert self.logger.handlers, 'At least one logging handler needed' # Redirect STDOUT to the logger if 'toprint' in kw: sys.stdout = LogStdout( self.logger, # Sets log level STDOUT is displayed under kw.get('prnlevel', logging.DEBUG) ) # Flag for turning on PDB in situ self.debug = kw.get('debug', False) # Flag for sending HTML-formatted exception tracebacks to the browser self.tohtml = kw.get('tohtml', False) # Write HTML-formatted exception tracebacks to a file if provided self.htmlfile = kw.get('htmlfile') def __call__(self, environ, start_response): # Make logger available to other WSGI apps/middlware if self.log: environ[LOGGERID] = self.logger # Make catch method available to other WSGI apps/middleware environ[CATCHID] = self.catch # Let exceptions "bubble up" to WSGI server/gateway if THROWERR in environ: return self.application(environ, start_response) # Try application try: return self.application(environ, start_response) # Log and/or report any errors except: return self.catch(environ, start_response) def catch(self, environ, start_response): '''Exception catcher.''' # Log exception if self.log: self.logger.exception(self.message) # Debug if self.debug: pdb.pm() # Write HTML-formatted exception tracebacks to a file if self.htmlfile is not None: open(self.htmlfile, 'wb').write(html(sys.exc_info())) # Send HTML-formatted exception tracebacks to the browser if self.tohtml: start_response(HTTPMSG, [('Content-type', 'text/html')]) return [html(sys.exc_info())] # Return error handler return self._errapp(environ, start_response)