fix(wsgi): Log SystemExit (with non-zero exit code) and KeyboardInterrupt (getsentry#380)

* Log SystemExit (with non-zero exit code) and KeyboardInterrupt in WSGI middleware

Neither SystemExit nor KeyboardInterrupt subclass Exception, so we must
explicitly handle these two exception classes in addition to Exception in the
WSGI middleware.

This is notably a direct port from raven-python:
 - https://github.com/getsentry/raven-python/blob/master/raven/middleware.py
 - https://github.com/getsentry/raven-python/blob/master/tests/middleware/tests.py

Fixes: getsentryGH-379

Author: saifelse

sentry_sdk/integrations/wsgi.py

@@ -87,7 +87,7 @@ def __call__(self, environ, start_response):
 
             try:
                 rv = self.app(environ, start_response)
-            except Exception:
+            except BaseException:
                 reraise(*_capture_exception(hub))
 
         return _ScopedResponse(hub, rv)
@@ -151,15 +151,22 @@ def get_client_ip(environ):
 
 def _capture_exception(hub):
     # type: (Hub) -> ExcInfo
+    exc_info = sys.exc_info()
+
     # Check client here as it might have been unset while streaming response
     if hub.client is not None:
-        exc_info = sys.exc_info()
-        event, hint = event_from_exception(
-            exc_info,
-            client_options=hub.client.options,
-            mechanism={"type": "wsgi", "handled": False},
-        )
-        hub.capture_event(event, hint=hint)
+        e = exc_info[1]
+
+        # SystemExit(0) is the only uncaught exception that is expected behavior
+        should_skip_capture = isinstance(e, SystemExit) and e.code in (0, None)
+        if not should_skip_capture:
+            event, hint = event_from_exception(
+                exc_info,
+                client_options=hub.client.options,
+                mechanism={"type": "wsgi", "handled": False},
+            )
+            hub.capture_event(event, hint=hint)
+
     return exc_info
 
 
@@ -181,7 +188,7 @@ def __iter__(self):
                     chunk = next(iterator)
                 except StopIteration:
                     break
-                except Exception:
+                except BaseException:
                     reraise(*_capture_exception(self._hub))
 
             yield chunk
@@ -192,7 +199,7 @@ def close(self):
                 self._response.close()
             except AttributeError:
                 pass
-            except Exception:
+            except BaseException:
                 reraise(*_capture_exception(self._hub))
 
 

tests/integrations/wsgi/test_wsgi.py

@@ -12,6 +12,28 @@ def app(environ, start_response):
     return app
 
 
+class IterableApp(object):
+    def __init__(self, iterable):
+        self.iterable = iterable
+
+    def __call__(self, environ, start_response):
+        return self.iterable
+
+
+class ExitingIterable(object):
+    def __init__(self, exc_func):
+        self._exc_func = exc_func
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        raise self._exc_func()
+
+    def next(self):
+        return type(self).__next__(self)
+
+
 def test_basic(sentry_init, crashing_app, capture_events):
     sentry_init(send_default_pii=True)
     app = SentryWsgiMiddleware(crashing_app)
@@ -30,3 +52,58 @@ def test_basic(sentry_init, crashing_app, capture_events):
         "query_string": "",
         "url": "http://localhost/",
     }
+
+
+@pytest.fixture(params=[0, None])
+def test_systemexit_zero_is_ignored(sentry_init, capture_events, request):
+    zero_code = request.param
+    sentry_init(send_default_pii=True)
+    iterable = ExitingIterable(lambda: SystemExit(zero_code))
+    app = SentryWsgiMiddleware(IterableApp(iterable))
+    client = Client(app)
+    events = capture_events()
+
+    with pytest.raises(SystemExit):
+        client.get("/")
+
+    assert len(events) == 0
+
+
+@pytest.fixture(params=["", "foo", 1, 2])
+def test_systemexit_nonzero_is_captured(sentry_init, capture_events, request):
+    nonzero_code = request.param
+    sentry_init(send_default_pii=True)
+    iterable = ExitingIterable(lambda: SystemExit(nonzero_code))
+    app = SentryWsgiMiddleware(IterableApp(iterable))
+    client = Client(app)
+    events = capture_events()
+
+    with pytest.raises(SystemExit):
+        client.get("/")
+
+    event, = events
+
+    assert "exception" in event
+    exc = event["exception"]["values"][-1]
+    assert exc["type"] == "SystemExit"
+    assert exc["value"] == nonzero_code
+    assert event["level"] == "error"
+
+
+def test_keyboard_interrupt_is_captured(sentry_init, capture_events):
+    sentry_init(send_default_pii=True)
+    iterable = ExitingIterable(lambda: KeyboardInterrupt())
+    app = SentryWsgiMiddleware(IterableApp(iterable))
+    client = Client(app)
+    events = capture_events()
+
+    with pytest.raises(KeyboardInterrupt):
+        client.get("/")
+
+    event, = events
+
+    assert "exception" in event
+    exc = event["exception"]["values"][-1]
+    assert exc["type"] == "KeyboardInterrupt"
+    assert exc["value"] == ""
+    assert event["level"] == "error"