eventlite 0.1a

Abstract

The purpose of this library is to provide an “abstract” way for functions to “report” events, in a way similar to how a logging system operates.

Some example applications:

• A logging system: emit('log', 'My message', level='info')

• Reporting progress on some running operation emit('progress', current=20, total=100)

Note that the event structure is not imposed in any way; in fact, any combination of arguments/keywords can be used, proven that the handler function is able to handle it.

Example usage

import eventlite

def myfunction(foo):
    eventlite.emit(foo)

def handler(foo):
    print('You said: {0}'.format('Hello'))

with eventlite.handler(handler):
    myfunction('Hello')

API Documentation

The library provides two functions:

• eventlite.emit(*a, **kw) “emits” an “event” (represented by a variable number of arguments / keywords).

• eventlite.handler(function) returns a context manager that makes events to be dispatched to a certain function, while the context is active.

So, in the example above, when eventlite.emit() is called with one argument, handler() will be called passing the single argument to it.

Internals

All the magic is implemented using a LocalStack (borrowed from werkzeug) which keeps a stack of handlers to be called, for the local proxy. The emit() functon simply looks for an handler in the stack to which to dispatch the event.

Note: by default only the handler for the innermost context

manager is called; this might or might not be the desired behavior; some way to change this will be added in the future.