feat: Debug-log all requests and responses

src/edge_proxy/middleware.py

@@ -0,0 +1,41 @@
+import time
+from typing import Any, Callable
+
+import structlog
+from fastapi import Request
+from starlette.middleware.base import BaseHTTPMiddleware
+
+logger = structlog.get_logger("edge_proxy.request")
+
+
+class RequestLoggingMiddleware(BaseHTTPMiddleware):
+    """
+    Log all incoming HTTP requests and responses with timing information.
+    """
+
+    async def dispatch(
+        self, request: Request, call_next: Callable[[Request], Any]
+    ) -> Any:
+        start_time = time.time()
+
+        logger.debug(
+            "request",
+            method=request.method,
+            url=request.url.path,
+            client_host=request.client.host if request.client else None,
+        )
+
+        response = await call_next(request)
+
+        duration = time.time() - start_time
+
+        logger.debug(
+            "response",
+            method=request.method,
+            url=request.url.path,
+            status_code=response.status_code,
+            size=int(response.headers.get("content-length", 0)),
+            duration_ms=round(duration * 1000),
+        )
+
+        return response

src/edge_proxy/server.py

@@ -14,6 +14,7 @@
 from edge_proxy.environments import EnvironmentService
 from edge_proxy.exceptions import FeatureNotFoundError, FlagsmithUnknownKeyError
 from edge_proxy.logging import setup_logging
+from edge_proxy.middleware import RequestLoggingMiddleware
 from edge_proxy.models import IdentityWithTraits
 from edge_proxy.settings import get_settings
 
@@ -113,6 +114,7 @@ async def refresh_cache():
     await environment_service.refresh_environment_caches()
 
 
+app.add_middleware(RequestLoggingMiddleware)
 app.add_middleware(
     CORSMiddleware,
     allow_origins=settings.allow_origins,

tests/test_middleware.py

@@ -0,0 +1,41 @@
+import json
+
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from pytest_mock import MockerFixture
+
+from edge_proxy.middleware import RequestLoggingMiddleware
+
+
+def test_request_logging_middleware(mocker: MockerFixture) -> None:
+    # Given
+    mock_logger = mocker.patch("edge_proxy.middleware.logger")
+
+    app = FastAPI()
+    app.add_middleware(RequestLoggingMiddleware)
+    response = "ok"
+
+    @app.get("/test")
+    async def test_endpoint():
+        return response
+
+    client = TestClient(app)
+
+    # When
+    client.get("/test")
+
+    # Then
+    mock_logger.debug.assert_any_call(
+        "request",
+        method="GET",
+        url="/test",
+        client_host="testclient",
+    )
+    mock_logger.debug.assert_any_call(
+        "response",
+        method="GET",
+        url="/test",
+        status_code=200,
+        size=len(json.dumps(response)),
+        duration_ms=mocker.ANY,
+    )