src/chokepoint/api/middleware.py

"""Request-id + timing middleware.

Every response carries `X-Request-ID`; every request logs one JSON line
(method, path, status, duration) tagged with that id, per §9's
cross-cutting requirements.
"""

from __future__ import annotations

import time
import uuid

from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.requests import Request
from starlette.responses import Response

from chokepoint.logging import get_logger

logger = get_logger("chokepoint.access")


class RequestContextMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request: Request, call_next: RequestResponseEndpoint) -> Response:
        request_id = str(uuid.uuid4())
        request.state.request_id = request_id
        start = time.perf_counter()

        response = await call_next(request)

        duration_ms = round((time.perf_counter() - start) * 1000, 2)
        response.headers["X-Request-ID"] = request_id
        logger.info(
            "request handled",
            extra={
                "request_id": request_id,
                "method": request.method,
                "path": request.url.path,
                "status_code": response.status_code,
                "duration_ms": duration_ms,
            },
        )
        return response