Update queueing

main.py

@@ -1,4 +1,5 @@
 import os
+import time
 import requests
 from fastapi import FastAPI, UploadFile, File, Form, Query, Request, Body
 from fastapi.responses import Response
@@ -20,6 +21,36 @@ HF_TOKEN = os.getenv("HF_TOKEN")
 
 DEV_URL = "https://PPAL-SongLab-UGA-fruit-analyzer-dev.hf.space"
 PROD_URL = "https://PPAL-SongLab-UGA-fruit-analyzer.hf.space"
+HF_RATE_LIMIT_STATUS = 429
+
+
+def request_with_429_backoff(method, url, *, max_retries=3, **kwargs):
+    last_response = None
+    for attempt in range(max_retries + 1):
+        response = method(url, **kwargs)
+        last_response = response
+        if response.status_code != HF_RATE_LIMIT_STATUS:
+            return response
+
+        retry_after = response.headers.get("retry-after")
+        try:
+            wait_s = float(retry_after) if retry_after else None
+        except ValueError:
+            wait_s = None
+        if wait_s is None:
+            wait_s = [2.0, 5.0, 10.0, 15.0][min(attempt, 3)]
+        if attempt < max_retries:
+            time.sleep(min(max(wait_s, 0.5), 20.0))
+    return last_response
+
+
+def hf_error_message(exc):
+    response = getattr(exc, "response", None)
+    if response is not None and response.status_code == HF_RATE_LIMIT_STATUS:
+        retry_after = response.headers.get("retry-after")
+        suffix = f" Retry after about {retry_after} seconds." if retry_after else " Please wait a minute and try again."
+        return f"Hugging Face is rate limiting this Space after several retry attempts.{suffix}"
+    return str(exc)
 
 @app.get("/")
 def read_root():
@@ -66,7 +97,14 @@ async def proxy_process(request: Request, file: UploadFile = File(...), password
 
     # FIX: Define the blocking request
     def make_post():
-        return requests.post(target_url, headers=headers, files=files, data=data, timeout=120)
+        return request_with_429_backoff(
+            requests.post,
+            target_url,
+            headers=headers,
+            files=files,
+            data=data,
+            timeout=120,
+        )
 
     try:
         # FIX: Run it in a background thread so other users can check the status!
@@ -74,7 +112,7 @@ async def proxy_process(request: Request, file: UploadFile = File(...), password
         response.raise_for_status()
         return response.json()
     except requests.exceptions.RequestException as e:
-        return {"success": False, "message": f"Proxy Error (Hugging Face): {str(e)}"}
+        return {"success": False, "message": f"Proxy Error (Hugging Face): {hf_error_message(e)}"}
     except Exception as e:
         return {"success": False, "message": f"Proxy Error (Internal): {str(e)}"}
 
@@ -87,14 +125,20 @@ async def proxy_batch_stage(payload: dict = Body(...)):
     headers = {"Authorization": f"Bearer {HF_TOKEN}"}
 
     def make_post():
-        return requests.post(target_url, headers=headers, json=payload, timeout=120)
+        return request_with_429_backoff(
+            requests.post,
+            target_url,
+            headers=headers,
+            json=payload,
+            timeout=120,
+        )
 
     try:
         response = await run_in_threadpool(make_post)
         response.raise_for_status()
         return response.json()
     except requests.exceptions.RequestException as e:
-        return {"success": False, "message": f"Proxy Error (Hugging Face): {str(e)}", "rows": []}
+        return {"success": False, "message": f"Proxy Error (Hugging Face): {hf_error_message(e)}", "rows": []}
     except Exception as e:
         return {"success": False, "message": f"Proxy Error (Internal): {str(e)}", "rows": []}