panel.chat.langchain module

The langchain module integrates Langchain support with Panel.

class panel.chat.langchain.PanelCallbackHandler(instance: ChatFeed | ChatInterface, user: str = 'LangChain', avatar: str = '🦜')

Bases: object

The Langchain PanelCallbackHandler itself is not a widget or pane, but is useful for rendering and streaming the chain of thought from Langchain Tools, Agents, and Chains as ChatMessage objects.

Reference: https://panel.holoviz.org/reference/chat/PanelCallbackHandler.html

Example:

>>> chat_interface = pn.widgets.ChatInterface(callback=callback, callback_user="Langchain")
>>> callback_handler = pn.widgets.langchain.PanelCallbackHandler(instance=chat_interface)
>>> llm = ChatOpenAI(streaming=True, callbacks=[callback_handler])
>>> chain = ConversationChain(llm=llm)

on_chat_model_start(serialized: dict[str, Any], messages: list, **kwargs: Any) → None

To prevent the inherited class from raising NotImplementedError, will not call super() here.

on_retriever_end(documents, **kwargs: Any) → Any

Run when Retriever ends running.

on_retriever_error(error: Exception | KeyboardInterrupt, **kwargs: Any) → Any

Run when Retriever errors.

on_text(text: str, **kwargs: Any)

Run when text is received.