Fix status code: split pipeline load from input parsing

pipeline loading -> 500
input parsing -> 400

Signed-off-by: Raphael Glon <oOraph@users.noreply.github.com>

api_inference_community/routes.py

@@ -13,6 +13,7 @@
     IMAGE,
     IMAGE_INPUTS,
     IMAGE_OUTPUTS,
+    KNOWN_TASKS,
     ffmpeg_convert,
     normalize_payload,
     parse_accept,
@@ -88,6 +89,15 @@ def already_left(request: Request) -> bool:
 async def pipeline_route(request: Request) -> Response:
     start = time.time()
 
+    task = os.environ["TASK"]
+
+    # Shortcut: quickly check the task is in enum: no need to go any further otherwise, as we know for sure that
+    # normalize_payload will fail below: this avoids us to wait for the pipeline to be loaded to return
+    if task not in KNOWN_TASKS:
+        msg = f"The task `{task}` is not recognized by api-inference-community"
+        logger.error(msg)
+        return JSONResponse({"error": msg}, status_code=400)
+
     if os.getenv("DISCARD_LEFT", "0").lower() in [
         "1",
         "true",
@@ -97,16 +107,30 @@ async def pipeline_route(request: Request) -> Response:
         return Response(status_code=204)
 
     payload = await request.body()
-    task = os.environ["TASK"]
+
     if os.getenv("DEBUG", "0") in {"1", "true"}:
         pipe = request.app.get_pipeline()
+
     try:
         pipe = request.app.get_pipeline()
         try:
             sampling_rate = pipe.sampling_rate
         except Exception:
             sampling_rate = None
+            if task in AUDIO_INPUTS:
+                msg = f"Sampling rate is expected for model for audio task {task}"
+                logger.error(msg)
+                return JSONResponse({"error": msg}, status_code=500)
+    except Exception as e:
+        return JSONResponse({"error": str(e)}, status_code=500)
+
+    try:
         inputs, params = normalize_payload(payload, task, sampling_rate=sampling_rate)
+    except EnvironmentError as e:
+        # Since we catch the environment edge cases earlier above, this should not happen here anymore
+        # harmless to keep it, just in case
+        logger.error("Error while parsing input %s", e)
+        return JSONResponse({"error": str(e)}, status_code=500)
     except ValidationError as e:
         errors = []
         for error in e.errors():
@@ -120,7 +144,9 @@ async def pipeline_route(request: Request) -> Response:
                 )
         return JSONResponse({"error": errors}, status_code=400)
     except Exception as e:
-        return JSONResponse({"error": str(e)}, status_code=500)
+        # We assume the payload is bad -> 400
+        logger.warning("Error while parsing input %s", e)
+        return JSONResponse({"error": str(e)}, status_code=400)
 
     accept = request.headers.get("accept", "")
     lora_adapter = request.headers.get("lora")

api_inference_community/validation.py

@@ -218,6 +218,7 @@ def check_inputs(inputs, tag):
     "zero-shot-classification",
 }
 
+KNOWN_TASKS = AUDIO_INPUTS.union(IMAGE_INPUTS).union(TEXT_INPUTS)
 
 AUDIO = [
     "flac",