Add logging and add mongodb connection pool

app/middleware.py

@@ -0,0 +1,62 @@
+"""
+HTTP request/response logging middleware for FastAPI.
+
+Normal requests (2xx/3xx):
+    INFO  — method, path, query_params, status_code, duration_ms
+
+Error responses (4xx):
+    WARNING — all above + request_body (truncated to 1000 chars)
+
+Server errors (5xx):
+    ERROR — all above + request_body (truncated to 1000 chars)
+"""
+
+import time
+
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.requests import Request
+from starlette.responses import Response
+
+from logger import logger
+
+_BODY_METHODS = frozenset({"POST", "PUT", "PATCH"})
+_BODY_MAX_LEN = 1000
+
+
+class RequestLoggingMiddleware(BaseHTTPMiddleware):
+    async def dispatch(self, request: Request, call_next) -> Response:
+        start = time.perf_counter()
+
+        # Read body only for methods that carry a payload
+        body: str | None = None
+        if request.method in _BODY_METHODS:
+            raw = await request.body()
+            body = raw.decode(errors="replace")[:_BODY_MAX_LEN]
+
+        response = await call_next(request)
+
+        duration_ms = round((time.perf_counter() - start) * 1000, 1)
+        status = response.status_code
+
+        base_fields = {
+            "method": request.method,
+            "path": request.url.path,
+            "query": str(request.query_params) or None,
+            "status": status,
+            "duration_ms": duration_ms,
+        }
+
+        if status >= 500:
+            logger.bind(**base_fields, request_body=body).error(
+                "{method} {path} → {status} ({duration_ms}ms)", **base_fields
+            )
+        elif status >= 400:
+            logger.bind(**base_fields, request_body=body).warning(
+                "{method} {path} → {status} ({duration_ms}ms)", **base_fields
+            )
+        else:
+            logger.bind(**base_fields).info(
+                "{method} {path} → {status} ({duration_ms}ms)", **base_fields
+            )
+
+        return response