be-lcca/src/main.py

import time
import logging
from os import path
from uuid import uuid1
from typing import Optional, Final


from fastapi import FastAPI, HTTPException, status
from fastapi.exceptions import RequestValidationError
from fastapi.responses import JSONResponse
from pydantic import ValidationError

from slowapi import _rate_limit_exceeded_handler
from slowapi.errors import RateLimitExceeded
from sqlalchemy import inspect
from sqlalchemy.exc import SQLAlchemyError
from sqlalchemy.orm import scoped_session
from sqlalchemy.ext.asyncio import async_scoped_session
from starlette.middleware.base import BaseHTTPMiddleware, RequestResponseEndpoint
from starlette.requests import Request
from starlette.routing import compile_path
from starlette.middleware.gzip import GZipMiddleware
from fastapi.middleware.cors import CORSMiddleware

from starlette.responses import Response, StreamingResponse, FileResponse
from starlette.staticfiles import StaticFiles
import logging

from src.enums import ResponseStatus
from src.logging import configure_logging
from src.rate_limiter import limiter
from src.api import api_router
from src.database.core import engine, async_session, collector_async_session
from src.exceptions import handle_exception
from src.middleware import RequestValidationMiddleware

log = logging.getLogger(__name__)

# we configure the logging level and format
configure_logging()

# we create the ASGI for the app
app = FastAPI(openapi_url="", title="LCCA API",
              description="Welcome to LCCA's API documentation!",
              version="0.1.0")
app.state.limiter = limiter

# we define the exception handlers
app.add_exception_handler(Exception, handle_exception)
app.add_exception_handler(HTTPException, handle_exception)
app.add_exception_handler(RequestValidationError, handle_exception)
app.add_exception_handler(RateLimitExceeded, handle_exception)
app.add_exception_handler(SQLAlchemyError, handle_exception)

from src.context import set_request_id, reset_request_id, get_request_id

app.add_middleware(RequestValidationMiddleware)


@app.middleware("http")
async def db_session_middleware(request: Request, call_next):
    request_id = str(uuid1())

    # we create a per-request id such that we can ensure that our session is scoped for a particular request.
    # see: https://github.com/tiangolo/fastapi/issues/726
    ctx_token = set_request_id(request_id)


    try:
        start_time = time.time()
        session = async_scoped_session(async_session, scopefunc=get_request_id)
        request.state.db = session()
        collector_session = async_scoped_session(collector_async_session, scopefunc=get_request_id)
        request.state.collector_db = collector_session()
        
        response = await call_next(request)
        process_time = (time.time() - start_time) * 1000
        
        from src.context import get_username, get_role, get_user_id, set_user_id, set_username, set_role
        
        # Pull from context or fallback to request.state.user
        username = get_username()
        role = get_role()
        user_id = get_user_id()
        
        user_obj = getattr(request.state, "user", None)
        if user_obj:
            # UserBase in this project
            u_id = getattr(user_obj, "user_id", None)
            u_name = getattr(user_obj, "name", None) or getattr(user_obj, "username", None)
            u_role = getattr(user_obj, "role", None)

            if not user_id and u_id:
                user_id = str(u_id)
                set_user_id(user_id)
            if not username and u_name:
                username = u_name
                set_username(username)
            if not role and u_role:
                role = u_role
                set_role(role)

        user_info_str = ""
        if username:
            user_info_str = f" | User: {username}"
        if role:
            user_info_str += f" ({role})"

        log.info(
            f"HTTP {request.method} {request.url.path} completed in {round(process_time, 2)}ms{user_info_str}",
            extra={
                "method": request.method,
                "path": request.url.path,
                "status_code": response.status_code,
                "duration_ms": round(process_time, 2),
                "user_id": user_id,
                "role": role,
            },
        )
    except Exception as e:
        # Generate an error_id here if it hasn't been generated yet
        error_id = getattr(request.state, "error_id", None)
        if not error_id:
            import uuid
            error_id = str(uuid.uuid1())
            request.state.error_id = error_id

        log.error(
            f"Request failed | Error ID: {error_id}",
            extra={
                "method": request.method,
                "path": request.url.path,
                "error": str(e),
                "error_id": error_id,
            },
            exc_info=True,
        )
        raise e from None
    finally:
        await request.state.db.close()
        await request.state.collector_db.close()

    reset_request_id(ctx_token)
    return response



@app.middleware("http")
async def add_security_headers(request: Request, call_next):
    response = await call_next(request)
    response.headers["Strict-Transport-Security"] = "max-age=31536000 ; includeSubDomains"
    return response

# class MetricsMiddleware(BaseHTTPMiddleware):
#     async def dispatch(self, request: Request, call_next: RequestResponseEndpoint) -> Response:
#         method = request.method
#         endpoint = request.url.path
#         tags = {"method": method, "endpoint": endpoint}

#         try:
#             start = time.perf_counter()
#             response = await call_next(request)
#             elapsed_time = time.perf_counter() - start
#             tags.update({"status_code": response.status_code})
#             metric_provider.counter("server.call.counter", tags=tags)
#             metric_provider.timer("server.call.elapsed", value=elapsed_time, tags=tags)
#             log.debug(f"server.call.elapsed.{endpoint}: {elapsed_time}")
#         except Exception as e:
#             metric_provider.counter("server.call.exception.counter", tags=tags)
#             raise e from None
#         return response


# app.add_middleware(ExceptionMiddleware)

app.include_router(api_router)