_launch_subprocess() — langchain Function Reference

Architecture documentation for the _launch_subprocess() function in _execution.py from the langchain codebase.

Function python LangChainCore Runnables called by 3

Entity Profile

LangChainCore→ Runnables→ _launch_subprocess() — langchain Function Reference

Dependency Diagram

graph TD
  235aaeeb_c270_5c14_f276_f59bd26a7819["_launch_subprocess()"]
  a7063f14_dbac_d9f7_9cc6_a20aa09f5461["_execution.py"]
  235aaeeb_c270_5c14_f276_f59bd26a7819 -->|defined in| a7063f14_dbac_d9f7_9cc6_a20aa09f5461
  ea98a366_f701_dc2d_901d_9954c6c58e48["spawn()"]
  ea98a366_f701_dc2d_901d_9954c6c58e48 -->|calls| 235aaeeb_c270_5c14_f276_f59bd26a7819
  338d8d25_6ab3_9c8d_1642_bc64d57428eb["spawn()"]
  338d8d25_6ab3_9c8d_1642_bc64d57428eb -->|calls| 235aaeeb_c270_5c14_f276_f59bd26a7819
  ba1b6b39_fb63_7014_9fdb_7866618f263b["spawn()"]
  ba1b6b39_fb63_7014_9fdb_7866618f263b -->|calls| 235aaeeb_c270_5c14_f276_f59bd26a7819
  style 235aaeeb_c270_5c14_f276_f59bd26a7819 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain_v1/langchain/agents/middleware/_execution.py lines 27–48

def _launch_subprocess(
    command: Sequence[str],
    *,
    env: Mapping[str, str],
    cwd: Path,
    preexec_fn: typing.Callable[[], None] | None,
    start_new_session: bool,
) -> subprocess.Popen[str]:
    return subprocess.Popen(  # noqa: S603
        list(command),
        stdin=subprocess.PIPE,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        cwd=cwd,
        text=True,
        encoding="utf-8",
        errors="replace",
        bufsize=1,
        env=env,
        preexec_fn=preexec_fn,  # noqa: PLW1509
        start_new_session=start_new_session,
    )