FastAPI Backend Development Bootcamp · 강의

FastAPI로 API 게이트웨이 구현

FastAPI를 사용하여 API 게이트웨이를 구축하고 여러 마이크로서비스에 요청을 라우팅하며 응답을 집계하는 방법을 배웁니다.

FastAPI로 API 게이트웨이 구현은(는) CoddyKit의 무료 FastAPI Backend Development Bootcamp 강의입니다. 이것은 4개 중 3번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 FastAPI Backend Development Bootcamp 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. FastAPI Backend Development Bootcamp 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

What's an API Gateway?

Imagine your microservices are different shops in a mall. An API Gateway is like the mall's main entrance or information desk.

It's a single entry point for all client requests.
It routes requests to the correct backend service.
It can combine responses from multiple services.
It handles shared tasks like authentication or logging.

This keeps your client apps simpler and your backend services focused.

Why FastAPI for a Gateway?

FastAPI is an excellent choice for building an API Gateway due to its modern features:

Asynchronous nature: It can handle many requests concurrently without blocking, perfect for proxying.
High performance: Built on Starlette and Pydantic, it's very fast.
Easy routing: FastAPI's intuitive routing makes directing requests simple.
Dependency Injection: Helps manage shared resources and logic efficiently.

It acts as a lightweight, powerful reverse proxy.

The Core Idea: Proxying Requests

The main job of an API Gateway is to act as a proxy. This means it receives a request from a client, forwards it to a backend service, and then sends the backend's response back to the client.

We'll use the httpx library in Python to make asynchronous HTTP requests to our backend services from within our FastAPI gateway.

First, make sure you have httpx installed: pip install httpx

Basic GET Request Proxy

Let's create a simple FastAPI gateway that proxies a GET request to a public dummy API. Our gateway endpoint /proxy-todo will fetch a todo item from jsonplaceholder.typicode.com.

import httpx
from fastapi import FastAPI
import uvicorn

app = FastAPI()
BACKEND_SERVICE_URL = "https://jsonplaceholder.typicode.com/todos/1"

@app.get("/proxy-todo")
async def proxy_todo_item():
    async with httpx.AsyncClient() as client:
        response = await client.get(BACKEND_SERVICE_URL)
        response.raise_for_status() # Raises HTTPStatusError for 4xx/5xx responses
        return response.json()

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

Forwarding Path Parameters

Often, backend services require dynamic data in their URLs, known as path parameters. Your API Gateway needs to capture these parameters from the client request and forward them to the correct backend URL.

Here, we proxy requests to /proxy-todos/{todo_id}, passing todo_id to the backend.

import httpx
from fastapi import FastAPI
import uvicorn

app = FastAPI()
BACKEND_BASE_URL = "https://jsonplaceholder.typicode.com"

@app.get("/proxy-todos/{todo_id}")
async def proxy_todo_item_by_id(todo_id: int):
    async with httpx.AsyncClient() as client:
        backend_url = f"{BACKEND_BASE_URL}/todos/{todo_id}"
        response = await client.get(backend_url)
        response.raise_for_status()
        return response.json()

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

Handling POST/PUT Request Bodies

For requests like POST or PUT, clients send data in the request body. Your API Gateway must receive this body and forward it to the backend service. FastAPI's Request object allows us to access the raw request body.

We'll use request.json() to get the JSON body and pass it to httpx.

import httpx
from fastapi import FastAPI, Request
import uvicorn

app = FastAPI()
BACKEND_POST_URL = "https://jsonplaceholder.typicode.com/posts"

@app.post("/proxy-post")
async def proxy_create_post(request: Request):
    body = await request.json() # Get the raw JSON body from the client
    async with httpx.AsyncClient() as client:
        # Forward the body to the backend service
        response = await client.post(BACKEND_POST_URL, json=body)
        response.raise_for_status()
        return response.json()

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

Aggregating Multiple Responses

One powerful feature of an API Gateway is response aggregation. This means the gateway can call multiple backend services, combine their individual responses, and return a single, unified response to the client.

This reduces the number of requests a client needs to make, simplifying client-side logic and potentially improving performance.

Example: User & Order Aggregation

Let's see an example where our gateway fetches user details from one backend and then a list of todos for that user from another, combining them into a single response.

import httpx
from fastapi import FastAPI
import uvicorn

app = FastAPI()
BACKEND_USERS_URL = "https://jsonplaceholder.typicode.com/users"
BACKEND_TODOS_URL = "https://jsonplaceholder.typicode.com/todos"

@app.get("/user-with-todos/{user_id}")
async def get_user_with_todos(user_id: int):
    async with httpx.AsyncClient() as client:
        # Fetch user details
        user_response = await client.get(f"{BACKEND_USERS_URL}/{user_id}")
        user_response.raise_for_status()
        user_data = user_response.json()

        # Fetch todos for that user
        todos_response = await client.get(f"{BACKEND_TODOS_URL}?userId={user_id}")
        todos_response.raise_for_status()
        todos_data = todos_response.json()

        # Combine the data before returning
        user_data["todos"] = todos_data
        return user_data

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

Cross-Cutting Concerns at Gateway

Besides routing and aggregation, API Gateways are perfect for handling cross-cutting concerns. These are features needed by many services but not central to any one service's business logic.

Authentication & Authorization: Validate tokens once at the gateway.
Logging & Monitoring: Centralized request logging.
Rate Limiting: Protect backend services from overload.
Caching: Cache common responses to speed up delivery.

This offloads work from individual microservices.

Gateway Benefits Check

Which of the following are key benefits of using an API Gateway in a microservices architecture?

API Gateway with FastAPI Recap

You've learned how to build a powerful API Gateway using FastAPI!

We understood what an API Gateway is and its benefits.
We leveraged FastAPI's async capabilities for efficient proxying.
We implemented basic GET, path parameter, and POST body forwarding.
We explored how to aggregate responses from multiple backend services.
You also saw how gateways centralize cross-cutting concerns.

FastAPI provides a robust and performant foundation for your microservice entry point!

자주 묻는 질문

“FastAPI로 API 게이트웨이 구현” 강의는 무료인가요?

네 — “FastAPI로 API 게이트웨이 구현” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 FastAPI Backend Development Bootcamp 강의 전체를 잠금 해제할 수 있습니다. FastAPI Backend Development Bootcamp 강의에는 총 4개의 강의가 포함되어 있습니다.

“FastAPI로 API 게이트웨이 구현”에서 뭘 배우나요?

FastAPI를 사용하여 API 게이트웨이를 구축하고 여러 마이크로서비스에 요청을 라우팅하며 응답을 집계하는 방법을 배웁니다. 브라우저에서 직접 실행하는 실습 코드로 FastAPI Backend Development Bootcamp을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

FastAPI Backend Development Bootcamp을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 FastAPI Backend Development Bootcamp은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 3번째 강의입니다.

“FastAPI로 API 게이트웨이 구현” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 FastAPI Backend Development Bootcamp 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 FastAPI Backend Development Bootcamp 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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