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author | Victor Stinner <victor.stinner@gmail.com> | 2015-02-04 16:14:33 +0100 |
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committer | Victor Stinner <victor.stinner@gmail.com> | 2015-02-04 16:14:33 +0100 |
commit | 9bd38238a1802923b4774e57f6c41462c5035eb1 (patch) | |
tree | 2c412a92ce40fed3dbe82f3e687190385d17535e | |
parent | 3c9adcd0d7c8c0931bb61c046456cc3150fd967d (diff) | |
download | cpython-9bd38238a1802923b4774e57f6c41462c5035eb1.tar.gz |
asyncio doc: explain how to display ResourceWarning in the debug mode section
-rw-r--r-- | Doc/library/asyncio-dev.rst | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/Doc/library/asyncio-dev.rst b/Doc/library/asyncio-dev.rst index ce1275b4e0..bf77a8fb79 100644 --- a/Doc/library/asyncio-dev.rst +++ b/Doc/library/asyncio-dev.rst @@ -14,16 +14,22 @@ This page lists common traps and explains how to avoid them. Debug mode of asyncio --------------------- -To enable the debug mode globally, set the environment variable -:envvar:`PYTHONASYNCIODEBUG` to ``1``. To see debug traces, set the log level -of the :ref:`asyncio logger <asyncio-logger>` to :py:data:`logging.DEBUG`. The -simplest configuration is:: +The implementation of :mod:`asyncio` module has been written for performances. +To development with asyncio, it's required to enable the debug checks to ease +the development of asynchronous code. - import logging - # ... - logging.basicConfig(level=logging.DEBUG) +Setup an application to enable all debug checks: -Examples of effects of the debug mode: +* Enable the asyncio debug mode globally by setting the environment variable + :envvar:`PYTHONASYNCIODEBUG` to ``1`` +* Set the log level of the :ref:`asyncio logger <asyncio-logger>` to + :py:data:`logging.DEBUG`. For example, call + ``logging.basicConfig(level=logging.DEBUG)`` at startup. +* Configure the :mod:`warnings` module to display :exc:`ResourceWarning` + warnings. For example, use the ``-Wdefault`` command line option of Python to + display them. + +Examples debug checks: * Log :ref:`coroutines defined but never "yielded from" <asyncio-coroutine-not-scheduled>` @@ -33,6 +39,8 @@ Examples of effects of the debug mode: * Log callbacks taking more than 100 ms to be executed. The :attr:`BaseEventLoop.slow_callback_duration` attribute is the minimum duration in seconds of "slow" callbacks. +* :exc:`ResourceWarning` warnings are emitted when transports and event loops + are :ref:`not closed explicitly <asyncio-close-transports>`. .. seealso:: @@ -372,14 +380,15 @@ traceback where the task was created. Example of log in debug mode:: :ref:`Detect coroutine objects never scheduled <asyncio-coroutine-not-scheduled>`. +.. _asyncio-close-transports: -Close transports ----------------- +Close transports and event loops +-------------------------------- When a transport is no more needed, call its ``close()`` method to release -resources. +resources. Event loops must also be closed explicitly. -If a transport (or an event loop) is not closed explicitly, a -:exc:`ResourceWarning` warning will be emitted in its destructor. The -:exc:`ResourceWarning` warnings are hidden by default: use the ``-Wd`` command -line option of Python to show them. +If a transport or an event loop is not closed explicitly, a +:exc:`ResourceWarning` warning will be emitted in its destructor. By default, +:exc:`ResourceWarning` warnings are ignored. The :ref:`Debug mode of asyncio +<asyncio-debug-mode>` section explains how to display them. |