logging.handlers.SocketHandler

Package logging :: Module handlers :: Class SocketHandler

[show private | hide private]

Class SocketHandler

Filterer --+    
           |    
     Handler --+
               |
              SocketHandler

Known Subclasses:: DatagramHandler

A handler class which writes logging records, in pickle format, to a streaming socket. The socket is kept open across logging calls. If the peer resets it, an attempt is made to reconnect on the next call. The pickle which is sent is that of the LogRecord's attribute dictionary (__dict__), so that the receiver does not need to have the logging module installed in order to process the logging event.

To unpickle the record at the receiving end into a LogRecord, use the makeLogRecord function.

Method Summary
	__init__(self, host, port) Initializes the handler with a specific host address and port.
	close(self) Closes the socket.
	createSocket(self) Try to create a socket, using an exponential backoff with a max retry time.
	emit(self, record) Emit a record.
	handleError(self, record) Handle an error during logging.
	makePickle(self, record) Pickles the record in binary format with a length prefix, and returns it ready for transmission across the socket.
	makeSocket(self) A factory method which allows subclasses to define the precise type of socket they want.
	send(self, s) Send a pickled string to the socket.
Inherited from Handler
	acquire(self) Acquire the I/O thread lock.
	createLock(self) Acquire a thread lock for serializing access to the underlying I/O.
	flush(self) Ensure all logging output has been flushed.
	format(self, record) Format the specified record.
	handle(self, record) Conditionally emit the specified logging record.
	release(self) Release the I/O thread lock.
	setFormatter(self, fmt) Set the formatter for this handler.
	setLevel(self, level) Set the logging level of this handler.
Inherited from Filterer
	addFilter(self, filter) Add the specified filter to this handler.
	filter(self, record) Determine if a record is loggable by consulting all the filters.
	removeFilter(self, filter) Remove the specified filter from this handler.

Method Details

init(self, host, port)
(Constructor)

Initializes the handler with a specific host address and port.

The attribute 'closeOnError' is set to 1 - which means that if a socket error occurs, the socket is silently closed and then reopened on the next logging call.

Overrides:: logging.Handler.__init__

close(self)

Closes the socket.

Overrides:: logging.Handler.close

createSocket(self)

Try to create a socket, using an exponential backoff with a max retry time. Thanks to Robert Olson for the original patch (SF #815911) which has been slightly refactored.

emit(self, record)

Emit a record.

Pickles the record and writes it to the socket in binary format. If there is an error with the socket, silently drop the packet. If there was a problem with the socket, re-establishes the socket.

Overrides:: logging.Handler.emit

handleError(self, record)

Handle an error during logging.

An error has occurred during logging. Most likely cause - connection lost. Close the socket so that we can retry on the next event.

Overrides:: logging.Handler.handleError

makePickle(self, record)

Pickles the record in binary format with a length prefix, and returns it ready for transmission across the socket.

makeSocket(self)

A factory method which allows subclasses to define the precise type of socket they want.

send(self, s)

Send a pickled string to the socket.

This function allows for partial sends which can happen when the network is busy.