simplify logging configuration

single default handler and formatter
don't remove handlers
configure level once using setLevel
document logging
reorganize logging tests

tests/test_basic.py

@@ -738,7 +738,6 @@ def test_teardown_request_handler_debug_mode(app, client):
 
 def test_teardown_request_handler_error(app, client):
     called = []
-    app.config['LOGGER_HANDLER_POLICY'] = 'never'
     app.testing = False
 
     @app.teardown_request
@@ -814,7 +813,6 @@ def test_before_after_request_order(app, client):
 
 
 def test_error_handling(app, client):
-    app.config['LOGGER_HANDLER_POLICY'] = 'never'
     app.testing = False
 
     @app.errorhandler(404)
@@ -860,7 +858,6 @@ def test_error_handler_unknown_code(app):
 
 
 def test_error_handling_processing(app, client):
-    app.config['LOGGER_HANDLER_POLICY'] = 'never'
     app.testing = False
 
     @app.errorhandler(500)
@@ -882,7 +879,6 @@ def test_error_handling_processing(app, client):
 
 
 def test_baseexception_error_handling(app, client):
-    app.config['LOGGER_HANDLER_POLICY'] = 'never'
     app.testing = False
 
     @app.route('/')
@@ -1021,6 +1017,34 @@ def test_trapping_of_all_http_exceptions(app, client):
         client.get('/fail')
 
 
+def test_error_handler_after_processor_error(app, client):
+    app.testing = False
+
+    @app.before_request
+    def before_request():
+        if trigger == 'before':
+            1 // 0
+
+    @app.after_request
+    def after_request(response):
+        if trigger == 'after':
+            1 // 0
+        return response
+
+    @app.route('/')
+    def index():
+        return 'Foo'
+
+    @app.errorhandler(500)
+    def internal_server_error(e):
+        return 'Hello Server Error', 500
+
+    for trigger in 'before', 'after':
+        rv = client.get('/')
+        assert rv.status_code == 500
+        assert rv.data == b'Hello Server Error'
+
+
 def test_enctype_debug_helper(app, client):
     from flask.debughelpers import DebugFilesKeyError
     app.debug = True
@@ -1425,7 +1449,6 @@ def test_test_app_proper_environ(app, client):
 
 def test_exception_propagation(app, client):
     def apprunner(config_key):
-        app.config['LOGGER_HANDLER_POLICY'] = 'never'
 
         @app.route('/')
         def index():

tests/test_helpers.py

@@ -9,20 +9,19 @@
     :license: BSD, see LICENSE for more details.
 """
 
-import pytest
-
+import datetime
 import os
 import uuid
-import datetime
 
-import flask
-from logging import StreamHandler
+import pytest
 from werkzeug.datastructures import Range
 from werkzeug.exceptions import BadRequest, NotFound
-from werkzeug.http import parse_cache_control_header, parse_options_header
-from werkzeug.http import http_date
+from werkzeug.http import http_date, parse_cache_control_header, \
+    parse_options_header
+
+import flask
 from flask._compat import StringIO, text_type
-from flask.helpers import get_debug_flag, make_response
+from flask.helpers import get_debug_flag
 
 
 def has_encoding(name):
@@ -660,94 +659,7 @@ class TestSendfile(object):
             flask.send_from_directory('static', 'bad\x00')
 
 
-class TestLogging(object):
-    def test_logger_cache(self):
-        app = flask.Flask(__name__)
-        logger1 = app.logger
-        assert app.logger is logger1
-        assert logger1.name == __name__
-        app.logger_name = __name__ + '/test_logger_cache'
-        assert app.logger is not logger1
-
-    def test_debug_log(self, capsys, app, client):
-        app.debug = True
-
-        @app.route('/')
-        def index():
-            app.logger.warning('the standard library is dead')
-            app.logger.debug('this is a debug statement')
-            return ''
-
-        @app.route('/exc')
-        def exc():
-            1 // 0
-
-        with client:
-            client.get('/')
-            out, err = capsys.readouterr()
-            assert 'WARNING in test_helpers [' in err
-            assert os.path.basename(__file__.rsplit('.', 1)[0] + '.py') in err
-            assert 'the standard library is dead' in err
-            assert 'this is a debug statement' in err
-
-            with pytest.raises(ZeroDivisionError):
-                client.get('/exc')
-
-    def test_debug_log_override(self, app):
-        app.debug = True
-        app.logger_name = 'flask_tests/test_debug_log_override'
-        app.logger.level = 10
-        assert app.logger.level == 10
-
-    def test_exception_logging(self, app, client):
-        out = StringIO()
-        app.config['LOGGER_HANDLER_POLICY'] = 'never'
-        app.logger_name = 'flask_tests/test_exception_logging'
-        app.logger.addHandler(StreamHandler(out))
-        app.testing = False
-
-        @app.route('/')
-        def index():
-            1 // 0
-
-        rv = client.get('/')
-        assert rv.status_code == 500
-        assert b'Internal Server Error' in rv.data
-
-        err = out.getvalue()
-        assert 'Exception on / [GET]' in err
-        assert 'Traceback (most recent call last):' in err
-        assert '1 // 0' in err
-        assert 'ZeroDivisionError:' in err
-
-    def test_processor_exceptions(self, app, client):
-        app.config['LOGGER_HANDLER_POLICY'] = 'never'
-        app.testing = False
-
-        @app.before_request
-        def before_request():
-            if trigger == 'before':
-                1 // 0
-
-        @app.after_request
-        def after_request(response):
-            if trigger == 'after':
-                1 // 0
-            return response
-
-        @app.route('/')
-        def index():
-            return 'Foo'
-
-        @app.errorhandler(500)
-        def internal_server_error(e):
-            return 'Hello Server Error', 500
-
-        for trigger in 'before', 'after':
-            rv = client.get('/')
-            assert rv.status_code == 500
-            assert rv.data == b'Hello Server Error'
-
+class TestUrlFor(object):
     def test_url_for_with_anchor(self, app, req_ctx):
 
         @app.route('/')

tests/test_logging.py

@@ -0,0 +1,91 @@
+import logging
+import sys
+
+import pytest
+
+from flask._compat import StringIO
+from flask.logging import default_handler, has_level_handler, \
+    wsgi_errors_stream
+
+
+@pytest.fixture(autouse=True)
+def reset_logging(monkeypatch):
+    root_handlers = logging.root.handlers[:]
+    root_level = logging.root.level
+
+    logger = logging.getLogger('flask.app')
+    logger.handlers = []
+    logger.setLevel(logging.NOTSET)
+
+    yield
+
+    logging.root.handlers[:] = root_handlers
+    logging.root.setLevel(root_level)
+
+    logger.handlers = []
+    logger.setLevel(logging.NOTSET)
+
+
+def test_logger(app):
+    assert app.logger.name == 'flask.app'
+    assert app.logger.level == logging.NOTSET
+    assert app.logger.handlers == [default_handler]
+
+
+def test_logger_debug(app):
+    app.debug = True
+    assert app.logger.level == logging.DEBUG
+    assert app.logger.handlers == [default_handler]
+
+
+def test_existing_handler(app):
+    logging.root.addHandler(logging.StreamHandler())
+    assert app.logger.level == logging.NOTSET
+    assert not app.logger.handlers
+
+
+def test_wsgi_errors_stream(app, client):
+    @app.route('/')
+    def index():
+        app.logger.error('test')
+        return ''
+
+    stream = StringIO()
+    client.get('/', errors_stream=stream)
+    assert 'ERROR in test_logging: test' in stream.getvalue()
+
+    assert wsgi_errors_stream._get_current_object() is sys.stderr
+
+    with app.test_request_context(errors_stream=stream):
+        assert wsgi_errors_stream._get_current_object() is stream
+
+
+def test_has_level_handler():
+    logger = logging.getLogger('flask.app')
+    assert not has_level_handler(logger)
+
+    handler = logging.StreamHandler()
+    logging.root.addHandler(handler)
+    assert has_level_handler(logger)
+
+    logger.propagate = False
+    assert not has_level_handler(logger)
+    logger.propagate = True
+
+    handler.setLevel(logging.ERROR)
+    assert not has_level_handler(logger)
+
+
+def test_log_view_exception(app, client):
+    @app.route('/')
+    def index():
+        raise Exception('test')
+
+    app.testing = False
+    stream = StringIO()
+    rv = client.get('/', errors_stream=stream)
+    assert rv.status_code == 500
+    assert rv.data
+    err = stream.getvalue()
+    assert 'Exception on / [GET]' in err
+    assert 'Exception: test' in err

tests/test_subclassing.py

@@ -9,8 +9,8 @@
     :copyright: (c) 2015 by Armin Ronacher.
     :license: BSD, see LICENSE for more details.
 """
+
 import flask
-from logging import StreamHandler
 
 from flask._compat import StringIO
 
@@ -22,16 +22,12 @@ def test_suppressed_exception_logging():
 
     out = StringIO()
     app = SuppressedFlask(__name__)
-    app.logger_name = 'flask_tests/test_suppressed_exception_logging'
-    app.logger.addHandler(StreamHandler(out))
 
     @app.route('/')
     def index():
-        1 // 0
+        raise Exception('test')
 
-    rv = app.test_client().get('/')
+    rv = app.test_client().get('/', errors_stream=out)
     assert rv.status_code == 500
     assert b'Internal Server Error' in rv.data
-
-    err = out.getvalue()
-    assert err == ''
+    assert not out.getvalue()

tests/test_templating.py

@@ -399,7 +399,7 @@ def test_templates_auto_reload_debug_run(app, monkeypatch):
     assert app.jinja_env.auto_reload == True
 
 
-def test_template_loader_debugging(test_apps):
+def test_template_loader_debugging(test_apps, monkeypatch):
     from blueprintapp import app
 
     called = []
@@ -419,19 +419,15 @@ def test_template_loader_debugging(test_apps):
             assert 'See http://flask.pocoo.org/docs/blueprints/#templates' in text
 
     with app.test_client() as c:
-        try:
-            old_load_setting = app.config['EXPLAIN_TEMPLATE_LOADING']
-            old_handlers = app.logger.handlers[:]
-            app.logger.handlers = [_TestHandler()]
-            app.config['EXPLAIN_TEMPLATE_LOADING'] = True
+        monkeypatch.setitem(app.config, 'EXPLAIN_TEMPLATE_LOADING', True)
+        monkeypatch.setattr(
+            logging.getLogger('flask'), 'handlers', [_TestHandler()]
+        )
 
-            with pytest.raises(TemplateNotFound) as excinfo:
-                c.get('/missing')
+        with pytest.raises(TemplateNotFound) as excinfo:
+            c.get('/missing')
 
-            assert 'missing_template.html' in str(excinfo.value)
-        finally:
-            app.logger.handlers[:] = old_handlers
-            app.config['EXPLAIN_TEMPLATE_LOADING'] = old_load_setting
+        assert 'missing_template.html' in str(excinfo.value)
 
     assert len(called) == 1
 

tests/test_testing.py

@@ -207,7 +207,6 @@ def test_session_transaction_needs_cookies(app):
 
 
 def test_test_client_context_binding(app, client):
-    app.config['LOGGER_HANDLER_POLICY'] = 'never'
     app.testing = False
 
     @app.route('/')