[2.7] bpo-33468: Add try-finally contextlib.contextmanager example (GH-7816) by taleinat · Pull Request #8427 · python/cpython
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@@ -24,22 +24,28 @@ Functions provided:
function for :keyword:`with` statement context managers, without needing to
create a class or separate :meth:`__enter__` and :meth:`__exit__` methods.
A simple example (this is not recommended as a real way of generating HTML!):: While many objects natively support use in with statements, sometimes a resource needs to be managed that isn't a context manager in its own right, and doesn't implement a ``close()`` method for use with ``contextlib.closing``
An abstract example would be the following to ensure correct resource management::
from contextlib import contextmanager
@contextmanager def tag(name): print "<%s>" % name yield print "</%s>" % name
>>> with tag("h1"): ... print "foo" ... <h1> foo </h1> def managed_resource(*args, **kwds): # Code to acquire resource, e.g.: resource = acquire_resource(*args, **kwds) try: yield resource finally: # Code to release resource, e.g.: release_resource(resource)
>>> with managed_resource(timeout=3600) as resource: ... # Resource is released at the end of this block, ... # even if code in the block raises an exception
The function being decorated must return a :term:`generator`-iterator when called. This iterator must yield exactly one value, which will be bound to Expand Down
A simple example (this is not recommended as a real way of generating HTML!):: While many objects natively support use in with statements, sometimes a resource needs to be managed that isn't a context manager in its own right, and doesn't implement a ``close()`` method for use with ``contextlib.closing``
An abstract example would be the following to ensure correct resource management::
from contextlib import contextmanager
@contextmanager def tag(name): print "<%s>" % name yield print "</%s>" % name
>>> with tag("h1"): ... print "foo" ... <h1> foo </h1> def managed_resource(*args, **kwds): # Code to acquire resource, e.g.: resource = acquire_resource(*args, **kwds) try: yield resource finally: # Code to release resource, e.g.: release_resource(resource)
>>> with managed_resource(timeout=3600) as resource: ... # Resource is released at the end of this block, ... # even if code in the block raises an exception
The function being decorated must return a :term:`generator`-iterator when called. This iterator must yield exactly one value, which will be bound to Expand Down