Async queue: /generate → job_id, /result/{id} polling

rest_api.py

@@ -1,9 +1,14 @@
 from fastapi import FastAPI, HTTPException
 from pydantic import BaseModel
+from concurrent.futures import ThreadPoolExecutor
+import uuid, time
 import wai_service
 
 app = FastAPI()
 
+EXEC = ThreadPoolExecutor(max_workers=1)
+JOBS = {}                        # job_id ➜ (start_ts, Future)
+
 class InferenceRequest(BaseModel):
     word: str
     optimized_letter: str
@@ -14,10 +19,25 @@ class InferenceRequest(BaseModel):
         extra = "allow" 
 
 @app.post("/generate")
-def generate(req: InferenceRequest):
+def enqueue(req: InferenceRequest):
+    """Start a job and return its UUID immediately."""
+    job_id = str(uuid.uuid4())
+    fut = EXEC.submit(wai_service.handler, dict(req.__dict__))
+    JOBS[job_id] = (time.time(), fut)
+    return {"job_id": job_id}
+    
+@app.get("/result/{job_id}")
+def get_result(job_id: str):
+    """Poll for job completion."""
+    if job_id not in JOBS:
+        raise HTTPException(404, "job_id not found")
+
+    start, fut = JOBS[job_id]
+    if not fut.done():
+        return {"status": "running", "elapsed": int(time.time() - start)}
+
     try:
-        payload = dict(req.__dict__) 
-        img_b64 = wai_service.handler(req.dict())
-        return {"image_base64": img_b64}
-    except Exception as e:
-        raise HTTPException(status_code=500, detail=str(e))
+        img = fut.result()
+        return {"status": "finished", "image_base64": img}
+    finally:
+        del JOBS[job_id]          # housekeeping