Pythongateway.py
Copy
1
import uuid
2
import time
3
import httpx
4
from fastapi import FastAPI, Request, Response
5
from fastapi.responses import JSONResponse
6
 
7
app = FastAPI(title="API Gateway")
8
 
9
UPSTREAM_BASE = "https://httpbin.org"  # Replace with your backend
10
 
11
@app.middleware("http")
12
async def add_request_headers(request: Request, call_next):
13
    request_id = str(uuid.uuid4())
14
    start = time.monotonic()
15
    response = await call_next(request)
16
    duration_ms = round((time.monotonic() - start) * 1000, 2)
17
    response.headers["X-Request-ID"] = request_id
18
    response.headers["X-Duration-Ms"] = str(duration_ms)
19
    return response
20
 
21
@app.api_route("/api/{path:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH"])
22
async def proxy(request: Request, path: str):
23
    upstream_url = f"{UPSTREAM_BASE}/{path}"
24
    body = await request.body()
25
 
26
    async with httpx.AsyncClient() as client:
27
        upstream_resp = await client.request(
28
            method=request.method,
29
            url=upstream_url,
30
            headers={k: v for k, v in request.headers.items() if k.lower() != "host"},
31
            content=body,
32
            params=dict(request.query_params),
33
        )
34
 
35
    return Response(
36
        content=upstream_resp.content,
37
        status_code=upstream_resp.status_code,
38
        headers=dict(upstream_resp.headers),
39
        media_type=upstream_resp.headers.get("content-type"),
40
    )
41
 
42
@app.get("/health")
43
async def health():
44
    try:
45
        async with httpx.AsyncClient(timeout=3) as client:
46
            resp = await client.get(f"{UPSTREAM_BASE}/status/200")
47
        return {"status": "healthy", "upstream": resp.status_code}
48
    except Exception as e:
49
        return JSONResponse({"status": "unhealthy", "error": str(e)}, status_code=503)
50