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Kyle-VerhoogEmanuele Palazzetti
Kyle-Verhoog
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Emanuele Palazzetti
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[pylons] Add middleware exception/error handling tests (#529)
* [pylons] replicate #463 * [pylons] add test coverage for exception throwing middleware
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‎tests/contrib/pylons/app/middleware.py‎

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from webob import Request, Response
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class ExceptionMiddleware(object):
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"""A middleware which raises an exception."""
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def __init__(self, app):
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self.app = app
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def __call__(self, environ, start_response):
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raise Exception('Middleware exception')
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class ExceptionToSuccessMiddleware(object):
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"""A middleware which catches any exceptions that occur in a later
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middleware and returns a successful request.
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"""
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def __init__(self, app):
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self.app = app
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def __call__(self, environ, start_response):
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req = Request(environ)
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try:
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response = req.get_response(self.app)
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except Exception:
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response = Response()
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response.status_int = 200
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response.body = 'An error has been handled appropriately'
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return response(environ, start_response)
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class ExceptionToClientErrorMiddleware(object):
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def __init__(self, app):
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self.app = app
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def __call__(self, environ, start_response):
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req = Request(environ)
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try:
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response = req.get_response(self.app)
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except Exception:
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response = Response()
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response.status_int = 404
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response.body = 'An error has occured with proper client error handling'
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return response(environ, start_response)

‎tests/contrib/pylons/test_pylons.py‎

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@@ -7,7 +7,7 @@
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from paste import fixture
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from paste.deploy import loadapp
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from ddtrace.ext import http
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from ddtrace.ext import http, errors
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from ddtrace.constants import SAMPLING_PRIORITY_KEY
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from ddtrace.contrib.pylons import PylonsTraceMiddleware
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@@ -25,9 +25,132 @@ def setUp(self):
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# initialize a real traced Pylons app
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self.tracer = get_dummy_tracer()
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wsgiapp = loadapp('config:test.ini', relative_to=PylonsTestCase.conf_dir)
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self._wsgiapp = wsgiapp
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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self.app = fixture.TestApp(app)
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def test_controller_exception(self):
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"""Ensure exceptions thrown in controllers can be handled.
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No error tags should be set in the span.
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"""
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from .app.middleware import ExceptionToSuccessMiddleware
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wsgiapp = ExceptionToSuccessMiddleware(self._wsgiapp)
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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app = fixture.TestApp(app)
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app.get(url_for(controller='root', action='raise_exception'))
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spans = self.tracer.writer.pop()
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ok_(spans, spans)
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eq_(len(spans), 1)
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span = spans[0]
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eq_(span.service, 'web')
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eq_(span.resource, 'root.raise_exception')
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eq_(span.error, 0)
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eq_(span.get_tag('http.status_code'), '200')
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eq_(span.get_tag(errors.ERROR_MSG), None)
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eq_(span.get_tag(errors.ERROR_TYPE), None)
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eq_(span.get_tag(errors.ERROR_STACK), None)
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def test_mw_exc_success(self):
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"""Ensure exceptions can be properly handled by other middleware.
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No error should be reported in the span.
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"""
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from .app.middleware import ExceptionMiddleware, ExceptionToSuccessMiddleware
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wsgiapp = ExceptionMiddleware(self._wsgiapp)
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wsgiapp = ExceptionToSuccessMiddleware(wsgiapp)
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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app = fixture.TestApp(app)
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app.get(url_for(controller='root', action='index'))
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spans = self.tracer.writer.pop()
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ok_(spans, spans)
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eq_(len(spans), 1)
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span = spans[0]
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eq_(span.service, 'web')
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eq_(span.resource, 'None.None')
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eq_(span.error, 0)
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eq_(span.get_tag('http.status_code'), '200')
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eq_(span.get_tag(errors.ERROR_MSG), None)
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eq_(span.get_tag(errors.ERROR_TYPE), None)
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eq_(span.get_tag(errors.ERROR_STACK), None)
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def test_middleware_exception(self):
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"""Ensure exceptions raised in middleware are properly handled.
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Uncaught exceptions should result in error tagged spans.
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"""
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from .app.middleware import ExceptionMiddleware
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wsgiapp = ExceptionMiddleware(self._wsgiapp)
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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app = fixture.TestApp(app)
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with assert_raises(Exception):
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app.get(url_for(controller='root', action='index'))
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spans = self.tracer.writer.pop()
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ok_(spans, spans)
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eq_(len(spans), 1)
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span = spans[0]
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eq_(span.service, 'web')
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eq_(span.resource, 'None.None')
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eq_(span.error, 1)
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eq_(span.get_tag('http.status_code'), '500')
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eq_(span.get_tag(errors.ERROR_MSG), 'Middleware exception')
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eq_(span.get_tag(errors.ERROR_TYPE), 'exceptions.Exception')
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ok_(span.get_tag(errors.ERROR_STACK))
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def test_exc_success(self):
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from .app.middleware import ExceptionToSuccessMiddleware
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wsgiapp = ExceptionToSuccessMiddleware(self._wsgiapp)
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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app = fixture.TestApp(app)
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app.get(url_for(controller='root', action='raise_exception'))
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spans = self.tracer.writer.pop()
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ok_(spans, spans)
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eq_(len(spans), 1)
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span = spans[0]
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eq_(span.service, 'web')
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eq_(span.resource, 'root.raise_exception')
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eq_(span.error, 0)
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eq_(span.get_tag('http.status_code'), '200')
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eq_(span.get_tag(errors.ERROR_MSG), None)
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eq_(span.get_tag(errors.ERROR_TYPE), None)
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eq_(span.get_tag(errors.ERROR_STACK), None)
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def test_exc_client_failure(self):
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from .app.middleware import ExceptionToClientErrorMiddleware
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wsgiapp = ExceptionToClientErrorMiddleware(self._wsgiapp)
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app = PylonsTraceMiddleware(wsgiapp, self.tracer, service='web')
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app = fixture.TestApp(app)
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app.get(url_for(controller='root', action='raise_exception'), status=404)
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spans = self.tracer.writer.pop()
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ok_(spans, spans)
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eq_(len(spans), 1)
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span = spans[0]
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eq_(span.service, 'web')
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eq_(span.resource, 'root.raise_exception')
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eq_(span.error, 0)
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eq_(span.get_tag('http.status_code'), '404')
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eq_(span.get_tag(errors.ERROR_MSG), None)
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eq_(span.get_tag(errors.ERROR_TYPE), None)
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eq_(span.get_tag(errors.ERROR_STACK), None)
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def test_success_200(self):
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res = self.app.get(url_for(controller='root', action='index'))
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eq_(res.status, 200)

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