use app.name as app.logger name

CHANGES.rst

@@ -18,6 +18,12 @@ Unreleased
     -   :meth:`Flask.finalize_request` is called for all unhandled
         exceptions even if there is no ``500`` error handler.
 
+-   :attr:`Flask.logger` takes the same name as
+    :attr:`Flask.name` (the value passed as
+    ``Flask(import_name)``. This reverts 1.0's behavior of always
+    logging to ``"flask.app"``, in order to support multiple apps in the
+    same process. This may require adjusting logging configuration.
+    :issue:`2866`.
 -   :meth:`flask.RequestContext.copy` includes the current session
     object in the request context copy. This prevents ``session``
     pointing to an out-of-date object. :issue:`2935`

docs/config.rst

@@ -382,7 +382,7 @@ The following configuration values are used internally by Flask:
 
 .. versionchanged:: 1.0
     ``LOGGER_NAME`` and ``LOGGER_HANDLER_POLICY`` were removed. See
-    :ref:`logging` for information about configuration.
+    :doc:`/logging` for information about configuration.
 
     Added :data:`ENV` to reflect the :envvar:`FLASK_ENV` environment
     variable.

docs/errorhandling.rst

@@ -231,7 +231,7 @@ errors, use ``getattr`` to get access it for compatibility.
 Logging
 -------
 
-See :ref:`logging` for information on how to log exceptions, such as by
+See :doc:`/logging` for information on how to log exceptions, such as by
 emailing them to admins.
 
 

docs/logging.rst

@@ -1,12 +1,12 @@
-.. _logging:
-
 Logging
 =======
 
-Flask uses standard Python :mod:`logging`. All Flask-related messages are
-logged under the ``'flask'`` logger namespace.
-:meth:`Flask.logger <flask.Flask.logger>` returns the logger named
-``'flask.app'``, and can be used to log messages for your application. ::
+Flask uses standard Python :mod:`logging`. Messages about your Flask
+application are logged with :meth:`app.logger <flask.Flask.logger>`,
+which takes the same name as :attr:`app.name <flask.Flask.name>`. This
+logger can also be used to log your own messages.
+
+.. code-block:: python
 
     @app.route('/login', methods=['POST'])
     def login():

src/flask/app.py

@@ -653,22 +653,26 @@ def preserve_context_on_exception(self):
 
     @locked_cached_property
     def logger(self):
-        """The ``'flask.app'`` logger, a standard Python
-        :class:`~logging.Logger`.
+        """A standard Python :class:`~logging.Logger` for the app, with
+        the same name as :attr:`name`.
 
-        In debug mode, the logger's :attr:`~logging.Logger.level` will be set
-        to :data:`~logging.DEBUG`.
+        In debug mode, the logger's :attr:`~logging.Logger.level` will
+        be set to :data:`~logging.DEBUG`.
 
-        If there are no handlers configured, a default handler will be added.
-        See :ref:`logging` for more information.
+        If there are no handlers configured, a default handler will be
+        added. See :doc:`/logging` for more information.
 
-        .. versionchanged:: 1.0
+        .. versionchanged:: 1.1.0
+            The logger takes the same name as :attr:`name` rather than
+            hard-coding ``"flask.app"``.
+
+        .. versionchanged:: 1.0.0
             Behavior was simplified. The logger is always named
-            ``flask.app``. The level is only set during configuration, it
-            doesn't check ``app.debug`` each time. Only one format is used,
-            not different ones depending on ``app.debug``. No handlers are
-            removed, and a handler is only added if no handlers are already
-            configured.
+            ``"flask.app"``. The level is only set during configuration,
+            it doesn't check ``app.debug`` each time. Only one format is
+            used, not different ones depending on ``app.debug``. No
+            handlers are removed, and a handler is only added if no
+            handlers are already configured.
 
         .. versionadded:: 0.3
         """

src/flask/logging.py

@@ -57,7 +57,10 @@ def has_level_handler(logger):
 
 
 def create_logger(app):
-    """Get the ``'flask.app'`` logger and configure it if needed.
+    """Get the the Flask apps's logger and configure it if needed.
+
+    The logger name will be the same as
+    :attr:`app.import_name <flask.Flask.name>`.
 
     When :attr:`~flask.Flask.debug` is enabled, set the logger level to
     :data:`logging.DEBUG` if it is not set.
@@ -66,7 +69,7 @@ def create_logger(app):
     :class:`~logging.StreamHandler` for
     :func:`~flask.logging.wsgi_errors_stream` with a basic format.
     """
-    logger = logging.getLogger("flask.app")
+    logger = logging.getLogger(app.name)
 
     if app.debug and logger.level == logging.NOTSET:
         logger.setLevel(logging.DEBUG)

tests/test_logging.py

@@ -23,7 +23,7 @@ def reset_logging(pytestconfig):
     logging.root.handlers = []
     root_level = logging.root.level
 
-    logger = logging.getLogger("flask.app")
+    logger = logging.getLogger("flask_test")
     logger.handlers = []
     logger.setLevel(logging.NOTSET)
 
@@ -42,7 +42,7 @@ def reset_logging(pytestconfig):
 
 
 def test_logger(app):
-    assert app.logger.name == "flask.app"
+    assert app.logger.name == "flask_test"
     assert app.logger.level == logging.NOTSET
     assert app.logger.handlers == [default_handler]
 

tests/test_templating.py

@@ -430,7 +430,9 @@ def handle(self, record):
 
     with app.test_client() as c:
         monkeypatch.setitem(app.config, "EXPLAIN_TEMPLATE_LOADING", True)
-        monkeypatch.setattr(logging.getLogger("flask"), "handlers", [_TestHandler()])
+        monkeypatch.setattr(
+            logging.getLogger("blueprintapp"), "handlers", [_TestHandler()]
+        )
 
         with pytest.raises(TemplateNotFound) as excinfo:
             c.get("/missing")