Toggle Menu
Prev Up Next

# `langchain_core.runnables.base`.chain

langchain_core.runnables.base.chain(func: Callable[[Input], Coroutine[Any, Any, Output]]) → Runnable[Input, Output]
langchain_core.runnables.base.chain(func: Callable[[Input], Iterator[Output]]) → Runnable[Input, Output]
langchain_core.runnables.base.chain(func: Callable[[Input], AsyncIterator[Output]]) → Runnable[Input, Output]
langchain_core.runnables.base.chain(func: Callable[[Input], Output]) → Runnable[Input, Output]

  Decorate a function to make it a Runnable. Sets the name of the runnable to the name of the function. Any runnables called by the function will be traced as dependencies.

  Parameters

    func – A callable.

  Returns

    A Runnable.

  Example:

      from langchain_core.runnables import chain
      from langchain_core.prompts import PromptTemplate
      from langchain_openai import OpenAI

      @chain
      def my_func(fields):
          prompt = PromptTemplate("Hello, {name}!")
          llm = OpenAI()
          formatted = prompt.invoke(**fields)

          for chunk in llm.stream(formatted):
              yield chunk

# Examples using chain

- %pip install -qU langchain langchain-community langchain-openai langchain-chroma

- Streaming With LangChain {#streaming-with-langchain}

- decorator.md