logging: add a decorator to log timing of functions or methods

Use it like that:

	from entrouvert.logging.decorators import timing

	@timing(0, 1, logger='timing')
	def method(arg0, arg1):
		etc...
		return arg0

	It will output lines to the logger named 'timing' at the DEBUG level::

		DEBUG module.method args: [arg0,arg1] entry: 23232.23232323
		DEBUG module.method args: [arg0,arg1] exit: 232334.23232323 duration: 232.2323

entrouvert/logging/decorators.py

@@ -0,0 +1,41 @@
+import logging
+import time
+from functools import wraps
+
+__all__ = [ 'timing' ]
+
+class TimingDecorator(object):
+    def __init__(self, *args_to_report, **kwargs):
+        if kwargs.get('logger'):
+            self.logger = logging.getLogger(kwargs.get('logger'))
+        else:
+            self.logger = logging.getLogger(__name__)
+        self.args_to_report = args_to_report
+
+    def __call__(self, func):
+        if hasattr(func, '__module__'): # functions
+            name = '{0}.{1}'.format(func.__name__, func.__module__)
+        else: # methods
+            name = '{0}.{1}.{2}'.format(func.__name__,
+                    func.__objclass__.__name__, func.__objclass__.__module__)
+        @wraps(func)
+        def f(*args, **kwargs):
+            print 'coin'
+            a = []
+            for i in self.args_to_report:
+                a.append(args[i])
+            a = unicode(a)
+            entry = time.time()
+            self.logger.debug('%(name)s args: %(args)s entry: %(entry)s', dict(
+                name=name, args=a, entry=entry))
+            try:
+                result = func(*args, **kwargs)
+            finally:
+                exit = time.time()
+                duration = exit - entry
+                self.logger.debug('%(name)s args: %(args)s exit: %(exit)s duration: %(duration)s', dict(
+                    name=name, args=a, exit=exit, duration=duration))
+            return result
+        return f
+
+timing = TimingDecorator