clean-python/clean_python/fastapi/fastapi_access_logger.py

# (c) Nelen & Schuurmans

import os
import time
from datetime import datetime
from typing import Awaitable
from typing import Callable
from typing import Optional

import inject
from starlette.background import BackgroundTasks
from starlette.requests import Request
from starlette.responses import Response

from clean_python import Gateway
from clean_python.fluentbit import FluentbitGateway

__all__ = ["FastAPIAccessLogger"]


class FastAPIAccessLogger:
    def __init__(self, hostname: str, gateway_override: Optional[Gateway] = None):
        self.origin = f"{hostname}-{os.getpid()}"
        self.gateway_override = gateway_override

    @property
    def gateway(self) -> Gateway:
        return self.gateway_override or inject.instance(FluentbitGateway)

    async def __call__(
        self, request: Request, call_next: Callable[[Request], Awaitable[Response]]
    ) -> Response:
        time_received = time.time()
        response = await call_next(request)
        request_time = time.time() - time_received

        # Instead of logging directly, set it as background task so that it is
        # executed after the response. See https://www.starlette.io/background/.
        if response.background is None:
            response.background = BackgroundTasks()
        response.background.add_task(
            log_access, self.gateway, request, response, time_received, request_time
        )
        return response


def fmt_timestamp(timestamp: float) -> str:
    return datetime.utcfromtimestamp(timestamp).isoformat() + "Z"


async def log_access(
    gateway: Gateway,
    request: Request,
    response: Response,
    time_received: float,
    request_time: float,
) -> None:
    """
    Create a dictionary with logging data.
    """
    try:
        content_length = int(response.headers.get("content-length"))
    except (TypeError, ValueError):
        content_length = None

    try:
        view_name = request.scope["route"].name
    except KeyError:
        view_name = None

    item = {
        "tag_suffix": "access_log",
        "remote_address": getattr(request.client, "host", None),
        "method": request.method,
        "path": request.url.path,
        "portal": request.url.netloc,
        "referer": request.headers.get("referer"),
        "user_agent": request.headers.get("user-agent"),
        "query_params": request.url.query,
        "view_name": view_name,
        "status": response.status_code,
        "content_type": response.headers.get("content-type"),
        "content_length": content_length,
        "time": fmt_timestamp(time_received),
        "request_time": request_time,
    }
    await gateway.add(item)