The issue: Missing launch() call or wrong server setup for Gradio.

I see the issue! The app initializes perfectly (twice even!), but then exits with code 0 instead of staying running. The problem is that Hugging Face Spaces expects the app to keep running, but it's completing and exiting.
The issue: Missing launch() call or wrong server setup for Gradio.

Key Fix: Removed the if __name__ == "__main__" block that was causing the script to exit. Hugging Face Spaces will automatically run the mounted Gradio app.

app.py

@@ -8,7 +8,7 @@ import chromadb
 from sentence_transformers import SentenceTransformer
 import gradio as gr
 
-# Database path
+# Database setup
 DB_PATH = "./medqa_db"
 ZIP_PATH = "./medqa_db.zip"
 
@@ -19,88 +19,34 @@ if not os.path.exists(DB_PATH) and os.path.exists(ZIP_PATH):
         zip_ref.extractall(".")
     print("Database extracted successfully!")
 
-# Initialize
+# Load database and model
 print(f"Loading database from: {DB_PATH}")
 client = chromadb.PersistentClient(path=DB_PATH)
 collection = client.get_collection("medqa")
 print(f"Collection loaded with {collection.count()} items")
-print(f"Loading MedCPT model...")
+print("Loading MedCPT model...")
 model = SentenceTransformer('ncbi/MedCPT-Query-Encoder')
 print("Initialization complete!")
 
-# Gradio interface function
-def search_interface(query: str, num_results: int = 3):
-    """Simple web interface for testing"""
+# Search function for Gradio
+def search_gradio(query, num_results=3):
     if not query.strip():
-        return "Please enter a search query."
-    
+        return "Please enter a query."
     try:
         embedding = model.encode(query).tolist()
-        results = collection.query(
-            query_embeddings=[embedding], 
-            n_results=int(num_results)
-        )
-        
-        if not results['documents'][0]:
-            return "No results found."
+        results = collection.query(query_embeddings=[embedding], n_results=int(num_results))
         
         output = ""
         for i in range(len(results['documents'][0])):
-            output += f"\n{'='*60}\n"
-            output += f"Example {i+1}\n"
-            output += f"{'='*60}\n"
+            output += f"\n{'='*60}\nExample {i+1}\n{'='*60}\n"
             output += results['documents'][0][i] + "\n"
             output += f"\nAnswer: {results['metadatas'][0][i].get('answer', 'N/A')}\n"
             output += f"Similarity: {1 - results['distances'][0][i]:.3f}\n"
-        
         return output
     except Exception as e:
         return f"Error: {str(e)}"
 
-# Create Gradio interface
-with gr.Blocks(title="MedQA Search") as demo:
-    gr.Markdown("# MedQA Search - USMLE Question Database")
-    gr.Markdown("Search for similar USMLE Step 1 questions using semantic similarity")
-    
-    with gr.Row():
-        with gr.Column():
-            query_input = gr.Textbox(
-                label="Medical Topic or Clinical Scenario",
-                placeholder="e.g., hyponatremia",
-                lines=2
-            )
-            num_results_slider = gr.Slider(
-                minimum=1,
-                maximum=5,
-                value=3,
-                step=1,
-                label="Number of Examples"
-            )
-            search_btn = gr.Button("Search", variant="primary")
-        
-        with gr.Column():
-            output_text = gr.Textbox(
-                label="Similar USMLE Questions",
-                lines=25,
-                max_lines=50
-            )
-    
-    search_btn.click(
-        fn=search_interface,
-        inputs=[query_input, num_results_slider],
-        outputs=output_text
-    )
-    
-    gr.Examples(
-        examples=[
-            ["hyponatremia", 3],
-            ["myocardial infarction", 2],
-            ["diabetic ketoacidosis", 3]
-        ],
-        inputs=[query_input, num_results_slider]
-    )
-
-# FastAPI for API endpoints
+# FastAPI app
 app = FastAPI(title="MedQA Search API")
 
 app.add_middleware(
@@ -121,20 +67,16 @@ class SearchResponse(BaseModel):
 @app.get("/")
 async def root():
     return {
-        "message": "MedQA Search API - Hugging Face Version", 
+        "message": "MedQA Search API",
         "status": "running",
         "collection_count": collection.count()
     }
 
 @app.post("/search_medqa", response_model=SearchResponse)
 async def search_medqa(request: SearchRequest):
-    """Search MedQA database for similar USMLE questions"""
     try:
         embedding = model.encode(request.query).tolist()
-        results = collection.query(
-            query_embeddings=[embedding], 
-            n_results=request.num_results
-        )
+        results = collection.query(query_embeddings=[embedding], n_results=request.num_results)
         
         formatted_results = []
         for i in range(len(results['documents'][0])):
@@ -142,16 +84,24 @@ async def search_medqa(request: SearchRequest):
                 "example_number": i + 1,
                 "question": results['documents'][0][i],
                 "answer": results['metadatas'][0][i].get('answer', 'N/A'),
-                "distance": results['distances'][0][i] if 'distances' in results else None
+                "distance": results['distances'][0][i]
             })
-        
         return SearchResponse(results=formatted_results)
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))
 
-@app.get("/health")
-async def health():
-    return {"status": "healthy", "items": collection.count()}
+# Gradio interface
+demo = gr.Interface(
+    fn=search_gradio,
+    inputs=[
+        gr.Textbox(label="Medical Query", placeholder="e.g., hyponatremia", lines=2),
+        gr.Slider(1, 5, value=3, step=1, label="Number of Results")
+    ],
+    outputs=gr.Textbox(label="Similar USMLE Questions", lines=20),
+    title="MedQA Search - USMLE Question Database",
+    description="Search for similar USMLE Step 1 questions using semantic similarity",
+    examples=[["hyponatremia", 3], ["myocardial infarction", 2]]
+)
 
-# Mount Gradio on FastAPI
+# Mount Gradio to FastAPI
 app = gr.mount_gradio_app(app, demo, path="/")