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API Gateway Problem2026-05-23

Context​

I am building a microservices architecture in Python using FastAPI and requests. The system consists of an API Gateway and two downstream services:

  1. API Gateway (Port 8000): Acts as a reverse proxy routing /users and /weather traffic.
  2. User Service (Port 8001): Returns basic JSON data.
  3. Weather Service (Port 8002): Reconstructs dynamic path/query parameters using FastAPI's Request object and forwards them to the Open-Meteo API.

Current Code​

gateway.py​

from fastapi import FastAPI
import requests

app = FastAPI()

@app.get("/users")
def get_users():
    return requests.get("http://127.0.0.1:8001/users").json()

@app.get("/weather")
def get_weather():
    weather_url = "https://api.open-meteo.com/v1/forecast?latitude=41.6639&longitude=-83.5552&current_weather=true"
    return requests.get(f"http://127.0.0.1:8002/weather/{weather_url}").json()

users.py​

from fastapi import FastAPI

app = FastAPI()

@app.get("/users")
def get_users():
    return {"Zayeem": "SWE", "Ahtasham": "BCE"}

weather.py​

import requests
from fastapi import FastAPI, Request

app = FastAPI()

@app.get("/weather/{weather_url:path}")
def get_weather(weather_url: str, request: Request):
    if request.url.query:
        weather_url = f"{weather_url}?{request.url.query}"

    response = requests.get(weather_url)
    if not response.ok:
        return {"error": "Downstream request failed", "details": response.text}

    return response.json()

Notes​

This setup shows two common gateway concerns:

  • Simple request forwarding to another internal service
  • Rebuilding dynamic path and query parameters before proxying to an external API