aiter() — langchain Function Reference

Architecture documentation for the aiter() function in streaming_aiter.py from the langchain codebase.

Function python LangChainCore ApiManagement

Entity Profile

LangChainCore→ ApiManagement→ aiter() — langchain Function Reference

Dependency Diagram

graph TD
  5a2284c4_e445_1a0c_e097_263832dc1143["aiter()"]
  026a405e_b843_1fc9_0384_15895a6c1500["AsyncIteratorCallbackHandler"]
  5a2284c4_e445_1a0c_e097_263832dc1143 -->|defined in| 026a405e_b843_1fc9_0384_15895a6c1500
  style 5a2284c4_e445_1a0c_e097_263832dc1143 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain/langchain_classic/callbacks/streaming_aiter.py lines 56–83

    async def aiter(self) -> AsyncIterator[str]:
        """Asynchronous iterator that yields tokens."""
        while not self.queue.empty() or not self.done.is_set():
            # Wait for the next token in the queue,
            # but stop waiting if the done event is set
            done, other = await asyncio.wait(
                [
                    # NOTE: If you add other tasks here, update the code below,
                    # which assumes each set has exactly one task each
                    asyncio.ensure_future(self.queue.get()),
                    asyncio.ensure_future(self.done.wait()),
                ],
                return_when=asyncio.FIRST_COMPLETED,
            )

            # Cancel the other task
            if other:
                other.pop().cancel()

            # Extract the value of the first completed task
            token_or_done = cast("str | Literal[True]", done.pop().result())

            # If the extracted value is the boolean True, the done event was set
            if token_or_done is True:
                break

            # Otherwise, the extracted value is a token, which we yield
            yield token_or_done