snapshot

backend/src/life_towers/logging.py

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+"""structlog JSON config and request logging middleware."""
+
+from __future__ import annotations
+
+import time
+import uuid as _uuid_mod
+
+import structlog
+from fastapi import Request, Response
+
+
+def configure_logging() -> None:
+    """Configure structlog for JSON output."""
+    structlog.configure(
+        processors=[
+            structlog.contextvars.merge_contextvars,
+            structlog.processors.add_log_level,
+            structlog.processors.TimeStamper(fmt="iso"),
+            structlog.processors.StackInfoRenderer(),
+            structlog.processors.JSONRenderer(),
+        ],
+        wrapper_class=structlog.make_filtering_bound_logger(0),
+        context_class=dict,
+        logger_factory=structlog.PrintLoggerFactory(),
+        cache_logger_on_first_use=True,
+    )
+
+
+async def request_logging_middleware(request: Request, call_next) -> Response:
+    """Log each request with method, path, status, duration_ms, user_id, request_id."""
+    request_id = str(_uuid_mod.uuid4())
+    structlog.contextvars.clear_contextvars()
+    structlog.contextvars.bind_contextvars(request_id=request_id)
+
+    # Extract user_id from Authorization header for logging (no DB call here)
+    auth = request.headers.get("Authorization") or request.headers.get("authorization")
+    user_id: str | None = None
+    if auth:
+        parts = auth.split()
+        if len(parts) == 2 and parts[0].lower() == "bearer":
+            user_id = parts[1]
+
+    start = time.monotonic()
+    response = await call_next(request)
+    duration_ms = round((time.monotonic() - start) * 1000, 2)
+
+    # request.client is rewritten by uvicorn's ProxyHeadersMiddleware
+    # (--proxy-headers) to the real client IP when behind a trusted reverse proxy.
+    client_ip = request.client.host if request.client else None
+
+    log = structlog.get_logger("access")
+    log.info(
+        "request",
+        method=request.method,
+        path=request.url.path,
+        status=response.status_code,
+        duration_ms=duration_ms,
+        user_id=user_id,
+        client_ip=client_ip,
+    )
+
+    response.headers["X-Request-Id"] = request_id
+    return response