Add ability to override default error handling behaviour

By default errors raised in side-effects functions are logged and then thrown
away. This is by design. Side-effects should not, by definition, halt the normal
flow, however in certain circumstances (e.g. testing) this may not be
desirable.

This commit introduces a setting 'SUPPRESS_ERRORS', which is True
by default, but can be overridden by setting the env var 'SIDE_EFFECTS_SUPPRESS_ERRORS'
to 'False'.

setup.py

@@ -8,20 +8,27 @@
 
 setup(
     name="django-side-effects",
-    version="0.2",
+    version="0.2.1",
     packages=find_packages(),
     include_package_data=True,
-    install_requires=['Django>=1.8'],
     description='Django app for managing external side effects.',
     long_description=README,
     url='https://github.com/yunojuno/django-side-effects',
+    install_requires=[
+        'django>=1.9',
+        'python-env-utils'
+    ],
     author='YunoJuno',
     author_email='[email protected]',
+    license='MIT',
     maintainer='YunoJuno',
     maintainer_email='[email protected]',
     classifiers=[
         'Environment :: Web Environment',
         'Framework :: Django',
+        'Framework :: Django :: 1.9',
+        'Framework :: Django :: 1.10',
+        'Framework :: Django :: 1.11',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: MIT License',
         'Operating System :: OS Independent',

side_effects/__init__.py

@@ -0,0 +1,2 @@
+# -*- coding: utf-8 -*-
+default_app_config = 'side_effects.apps.SideEffectsConfig'

side_effects/registry.py

@@ -3,12 +3,13 @@
 This module contains the Registry class that is responsible for managing
 all of the registered side-effects.
 """
-from __future__ import unicode_literals
-
 from collections import defaultdict
 import logging
 import threading
 
+from . import settings
+
+
 logger = logging.getLogger(__name__)
 
 
@@ -91,7 +92,10 @@ def _run_func(func, *args, **kwargs):
     try:
         func(*args, **kwargs)
     except Exception:
-        logger.exception("Error running side_effect function '%s'", fname(func))
+        if settings.SUPPRESS_ERRORS:
+            logger.exception("Error running side_effect function '%s'", fname(func))
+        else:
+            raise
 
 
 # global registry

side_effects/settings.py

@@ -0,0 +1,11 @@
+from env_utils import get_bool
+
+from django.conf import settings
+
+# If True then do not raise exceptions caught when running
+# side-effects, but just log them instead.
+# Default = True
+SUPPRESS_ERRORS = getattr(
+    settings, 'SIDE_EFFECTS_SUPPRESS_ERRORS',
+    get_bool('SIDE_EFFECTS_SUPPRESS_ERRORS', True)
+)

side_effects/tests.py

@@ -1,10 +1,11 @@
 # -*- coding: utf-8 -*-
-from __future__ import unicode_literals
+from __future__ import absolute_import
+
+import mock
 
 from django.test import TestCase
 
-from . import registry, decorators
-from .compat import mock
+from . import registry, decorators, settings
 
 
 def test_func_no_docstring(arg1, kwarg1=None):
@@ -101,6 +102,10 @@ def test__run_func(self):
             registry._run_func(test_func_exception)
             self.assertEqual(mock_logger.exception.call_count, 1)
 
+        # if the func raises an exception we should log it but not fail
+        settings.SUPPRESS_ERRORS = False
+        self.assertRaises(Exception, registry._run_func, test_func_exception)
+
 
 class RegistryTests(TestCase):
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py{27,36}-django{18,19,110,111}
+envlist = py{27,36}-django{19,110,111}
 
 [testenv]
 deps =
@@ -11,7 +11,6 @@ deps =
     django111: Django==1.11
 
 commands=
-    python --version
     coverage erase
     coverage run --include=side_effects/* manage.py test side_effects
     coverage report