Implement /__error__ endpoint (#123)

* Implement /__error__ endpoint

* Pin setuptools

* Fix fastapi tests

* Pin alembic

Author: leplatrem

src/dockerflow/django/middleware.py

@@ -32,6 +32,7 @@ class DockerflowMiddleware(MiddlewareMixin):
         (re.compile(r"/__version__/?$"), views.version),
         (re.compile(r"/__heartbeat__/?$"), views.heartbeat),
         (re.compile(r"/__lbheartbeat__/?$"), views.lbheartbeat),
+        (re.compile(r"/__error__/?$"), views.error),
     ]
 
     def __init__(self, get_response=None, *args, **kwargs):

src/dockerflow/django/views.py

@@ -75,3 +75,11 @@ def heartbeat(request):
         payload["checks"] = check_results.statuses
         payload["details"] = check_results.details
     return JsonResponse(payload, status=status_code)
+
+
+def error(request):
+    """
+    A view that raises an exception, used to test error handling.
+    """
+    logger.error("The __error__ endpoint was called")
+    raise Exception("This is a test exception from the /__error__ endpoint.")

src/dockerflow/fastapi/__init__.py

@@ -1,14 +1,15 @@
 from fastapi import APIRouter
 from fastapi.routing import APIRoute
 
-from .views import heartbeat, lbheartbeat, version
+from .views import error, heartbeat, lbheartbeat, version
 
 router = APIRouter(
     tags=["Dockerflow"],
     routes=[
         APIRoute("/__lbheartbeat__", endpoint=lbheartbeat, methods=["GET", "HEAD"]),
         APIRoute("/__heartbeat__", endpoint=heartbeat, methods=["GET", "HEAD"]),
         APIRoute("/__version__", endpoint=version, methods=["GET"]),
+        APIRoute("/__error__", endpoint=error, methods=["GET"]),
     ],
 )
 """This router adds the Dockerflow views."""

src/dockerflow/fastapi/views.py

@@ -1,3 +1,4 @@
+import logging
 import os
 
 from fastapi import Request, Response
@@ -6,6 +7,8 @@
 
 from ..version import get_version
 
+logger = logging.getLogger(__name__)
+
 
 def lbheartbeat():
     return {"status": "ok"}
@@ -42,3 +45,11 @@ def version(request: Request):
     else:
         root = "/app"
     return get_version(root)
+
+
+def error(request: Request):
+    """
+    A view that raises an exception, used to test error handling.
+    """
+    logger.error("The __error__ endpoint was called")
+    raise Exception("This is a test exception from the /__error__ endpoint.")

src/dockerflow/flask/app.py

@@ -177,6 +177,7 @@ def init_app(self, app):
             ("/__version__", "version", self._version_view),
             ("/__heartbeat__", "heartbeat", self._heartbeat_view),
             ("/__lbheartbeat__", "lbheartbeat", self._lbheartbeat_view),
+            ("/__error__", "error", self._error_view),
         ):
             self._blueprint.add_url_rule(*view)
         self._blueprint.before_app_request(self._before_request)
@@ -346,6 +347,13 @@ def render(status_code):
             heartbeat_failed.send(self, level=check_results.level)
             raise HeartbeatFailure(response=render(status_code))
 
+    def _error_view(self):
+        """
+        A view that raises an exception, used to test error handling.
+        """
+        self.logger.error("The __error__ endpoint was called")
+        raise Exception("This is a test exception from the /__error__ endpoint.")
+
     def version_callback(self, func):
         """
         A decorator to optionally register a new Dockerflow version callback

src/dockerflow/sanic/app.py

@@ -130,6 +130,7 @@ def init_app(self, app):
             ("/__version__", "version", self._version_view),
             ("/__heartbeat__", "heartbeat", self._heartbeat_view),
             ("/__lbheartbeat__", "lbheartbeat", self._lbheartbeat_view),
+            ("/__error__", "error", self._error_view),
         ):
             app.add_route(handler, uri, name="dockerflow." + name)
         app.middleware("request")(extract_request_id)
@@ -200,6 +201,13 @@ async def _version_view(self, request):
         else:
             return response.json(version_json)
 
+    async def _error_view(self, request):
+        """
+        A view that raises an exception, used to test error handling.
+        """
+        self.logger.error("The __error__ endpoint was called")
+        raise Exception("This is a test exception from the /__error__ endpoint.")
+
     async def _lbheartbeat_view(self, request):
         """
         Lets the load balancer know the application is running and available.

tests/constraints/flask-2.0.txt

@@ -1,4 +1,5 @@
 Flask<2.1
 Werkzeug<2.1.0
 SQLAlchemy<=1.4
-Flask-SQLAlchemy<3.0
+Flask-SQLAlchemy<3.0
+alembic<1.7

tests/constraints/flask-2.1.txt

@@ -1,4 +1,5 @@
 Flask<2.2
 SQLAlchemy<=1.4
 Flask-SQLAlchemy<3.0
-Werkzeug<3
+Werkzeug<3
+alembic<1.7

tests/django/test_django.py

@@ -134,6 +134,17 @@ def test_lbheartbeat_makes_no_db_queries(dockerflow_middleware, rf):
     assert len(queries) == 0
 
 
+def test_error_returns_500_and_logs_error(dockerflow_middleware, rf, caplog):
+    request = rf.get("/__error__")
+    with caplog.at_level(logging.INFO, logger="dockerflow.django"):
+        with pytest.raises(Exception, match="__error__ endpoint"):
+            dockerflow_middleware.process_request(request)
+    assert len(caplog.records) == 1
+    record = caplog.records[0]
+    assert record.getMessage() == "The __error__ endpoint was called"
+    assert record.levelno == logging.ERROR
+
+
 @pytest.mark.django_db()
 def test_redis_check(client, settings):
     settings.DOCKERFLOW_CHECKS = ["dockerflow.django.checks.check_redis_connected"]

tests/fastapi/test_fastapi.py

@@ -262,3 +262,14 @@ def return_error():
 
     response = client.get("/__heartbeat__")
     assert response.json()["checks"]["my_check_name"]
+
+
+def test_error_returns_500_and_logs_error(app, caplog):
+    client = TestClient(app, raise_server_exceptions=False)
+    response = client.get("/__error__")
+    assert response.status_code == 500
+    assert len(caplog.records) >= 1
+    record = caplog.records[0]
+    assert record.name == "dockerflow.fastapi.views"
+    assert record.getMessage() == "The __error__ endpoint was called"
+    assert record.levelno == logging.ERROR