Fix build error

main.py

@@ -22,14 +22,15 @@ 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
+HF_TRANSIENT_STATUS = {429, 502, 503, 504}
 
 
-def request_with_429_backoff(method, url, *, max_retries=3, **kwargs):
+def request_with_hf_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:
+        if response.status_code not in HF_TRANSIENT_STATUS:
             return response
 
         retry_after = response.headers.get("retry-after")
@@ -38,7 +39,7 @@ def request_with_429_backoff(method, url, *, max_retries=3, **kwargs):
         except ValueError:
             wait_s = None
         if wait_s is None:
-            wait_s = [2.0, 5.0, 10.0, 15.0][min(attempt, 3)]
+            wait_s = [2.0, 5.0, 10.0, 15.0][min(attempt, 3)] if response.status_code == HF_RATE_LIMIT_STATUS else [3.0, 8.0, 15.0, 20.0][min(attempt, 3)]
         if attempt < max_retries:
             time.sleep(min(max(wait_s, 0.5), 20.0))
     return last_response
@@ -50,8 +51,28 @@ def hf_error_message(exc):
         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}"
+    if response is not None and response.status_code in {502, 503, 504}:
+        return "Hugging Face Space is temporarily unavailable or waking up after several retry attempts. Please wait a moment and try again."
+    if isinstance(exc, requests.exceptions.Timeout):
+        return "Hugging Face Space did not respond before the proxy timeout. Please try again."
+    if isinstance(exc, requests.exceptions.ConnectionError):
+        return "Could not connect to the Hugging Face Space. Please try again."
     return str(exc)
 
+
+def is_retryable_hf_exception(exc):
+    response = getattr(exc, "response", None)
+    return bool(response is not None and response.status_code in HF_TRANSIENT_STATUS)
+
+
+def proxy_error_payload(prefix, exc, **extra):
+    return {
+        "success": False,
+        "message": f"{prefix}: {hf_error_message(exc)}",
+        "retryable": is_retryable_hf_exception(exc),
+        **extra,
+    }
+
 @app.get("/")
 def read_root():
     return {"status": "Render Proxy is awake!"}
@@ -97,7 +118,7 @@ async def proxy_process(request: Request, file: UploadFile = File(...), password
 
     # FIX: Define the blocking request
     def make_post():
-        return request_with_429_backoff(
+        return request_with_hf_backoff(
             requests.post,
             target_url,
             headers=headers,
@@ -112,7 +133,7 @@ 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): {hf_error_message(e)}"}
+        return proxy_error_payload("Proxy Error (Hugging Face)", e)
     except Exception as e:
         return {"success": False, "message": f"Proxy Error (Internal): {str(e)}"}
 
@@ -135,7 +156,7 @@ async def proxy_compatibility(request: Request, password: str = Form(""), userna
     data.setdefault("username", username)
 
     def make_post():
-        return request_with_429_backoff(
+        return request_with_hf_backoff(
             requests.post,
             target_url,
             headers=headers,
@@ -149,7 +170,7 @@ async def proxy_compatibility(request: Request, password: str = Form(""), userna
         response.raise_for_status()
         return response.json()
     except requests.exceptions.RequestException as e:
-        return {"success": False, "message": f"Proxy Error (Hugging Face): {hf_error_message(e)}", "results": []}
+        return proxy_error_payload("Proxy Error (Hugging Face)", e, results=[])
     except Exception as e:
         return {"success": False, "message": f"Proxy Error (Internal): {str(e)}", "results": []}
 
@@ -162,7 +183,7 @@ async def proxy_batch_stage(payload: dict = Body(...)):
     headers = {"Authorization": f"Bearer {HF_TOKEN}"}
 
     def make_post():
-        return request_with_429_backoff(
+        return request_with_hf_backoff(
             requests.post,
             target_url,
             headers=headers,
@@ -175,7 +196,7 @@ async def proxy_batch_stage(payload: dict = Body(...)):
         response.raise_for_status()
         return response.json()
     except requests.exceptions.RequestException as e:
-        return {"success": False, "message": f"Proxy Error (Hugging Face): {hf_error_message(e)}", "rows": []}
+        return proxy_error_payload("Proxy Error (Hugging Face)", e, rows=[])
     except Exception as e:
         return {"success": False, "message": f"Proxy Error (Internal): {str(e)}", "rows": []}