_astream() — langchain Function Reference

Architecture documentation for the _astream() function in chat_models.py from the langchain codebase.

Function python LangChainCore LanguageModelBase called by 2

Entity Profile

LangChainCore→ LanguageModelBase→ _astream() — langchain Function Reference

Dependency Diagram

graph TD
  eeec016b_d16e_6911_a23c_361548b5728f["_astream()"]
  48aa29b8_65e7_522f_a445_a441eeb6baff["BaseChatModel"]
  eeec016b_d16e_6911_a23c_361548b5728f -->|defined in| 48aa29b8_65e7_522f_a445_a441eeb6baff
  9d211053_b2a3_2915_b514_1f332955694a["astream()"]
  9d211053_b2a3_2915_b514_1f332955694a -->|calls| eeec016b_d16e_6911_a23c_361548b5728f
  d2cd58bb_554b_a407_049a_8aaad431d049["_agenerate_with_cache()"]
  d2cd58bb_554b_a407_049a_8aaad431d049 -->|calls| eeec016b_d16e_6911_a23c_361548b5728f
  style eeec016b_d16e_6911_a23c_361548b5728f fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/language_models/chat_models.py lines 1455–1491

    async def _astream(
        self,
        messages: list[BaseMessage],
        stop: list[str] | None = None,
        run_manager: AsyncCallbackManagerForLLMRun | None = None,
        **kwargs: Any,
    ) -> AsyncIterator[ChatGenerationChunk]:
        """Stream the output of the model.

        Args:
            messages: The messages to generate from.
            stop: Optional list of stop words to use when generating.
            run_manager: Optional callback manager to use for this call.
            **kwargs: Additional keyword arguments to pass to the model.

        Yields:
            The chat generation chunks.
        """
        iterator = await run_in_executor(
            None,
            self._stream,
            messages,
            stop,
            run_manager.get_sync() if run_manager else None,
            **kwargs,
        )
        done = object()
        while True:
            item = await run_in_executor(
                None,
                next,
                iterator,
                done,
            )
            if item is done:
                break
            yield item  # type: ignore[misc]