error handling

README.md

@@ -5,6 +5,7 @@ colorFrom: purple
 colorTo: indigo
 sdk: docker
 pinned: false
+app_port: 7860
 ---
 
 # Paul Graham Essay Explorer 🤖

app.py

@@ -168,13 +168,19 @@ async def start_chat():
 
     The user session is a dictionary that is unique to each user session, and is stored in the memory of the server.
     """
-
-    lcel_rag_chain = (
-        {"context": itemgetter("query") | hf_retriever, "query": itemgetter("query")}
-        | rag_prompt | hf_llm
-    )
-
-    cl.user_session.set("lcel_rag_chain", lcel_rag_chain)
+    try:
+        lcel_rag_chain = (
+            {"context": itemgetter("query") | hf_retriever, "query": itemgetter("query")}
+            | rag_prompt | hf_llm
+        )
+
+        cl.user_session.set("lcel_rag_chain", lcel_rag_chain)
+    except Exception as e:
+        await cl.Message(
+            content="I apologize, but I'm having trouble initializing the chat. Please refresh the page and try again.",
+            author="System"
+        ).send()
+        raise e  # Re-raise the exception to prevent the chat from starting in a broken state
 
 @cl.on_message  
 async def main(message: cl.Message):
@@ -185,14 +191,27 @@ async def main(message: cl.Message):
 
     The LCEL RAG chain is stored in the user session, and is unique to each user session - this is why we can access it here.
     """
-    lcel_rag_chain = cl.user_session.get("lcel_rag_chain")
-
-    msg = cl.Message(content="")
-
-    for chunk in await cl.make_async(lcel_rag_chain.stream)(
-        {"query": message.content},
-        config=RunnableConfig(callbacks=[cl.LangchainCallbackHandler()]),
-    ):
-        await msg.stream_token(chunk)
-
-    await msg.send()
+    try:
+        lcel_rag_chain = cl.user_session.get("lcel_rag_chain")
+
+        msg = cl.Message(content="")
+
+        async for chunk in await cl.make_async(lcel_rag_chain.stream)(
+            {"query": message.content},
+            config=RunnableConfig(callbacks=[cl.LangchainCallbackHandler()]),
+        ):
+            await msg.stream_token(chunk)
+
+        await msg.send()
+    except Exception as e:
+        error_message = str(e)
+        if "Connection reset by peer" in error_message or "Connection aborted" in error_message:
+            await cl.Message(
+                content="I apologize, but I'm having trouble connecting to the language model right now. Please try again in a few moments. If the problem persists, the service might be temporarily unavailable.",
+                author="System"
+            ).send()
+        else:
+            await cl.Message(
+                content=f"An error occurred: {error_message}. Please try again.",
+                author="System"
+            ).send()