Module spawn 

Spawning a subagent process.

A subagent is the same binary re-exec’d with AGENT_SUBAGENT set, so the one artifact is CLI, supervisor, and subagent. Each child is put in its own process group (setpgid in pre_exec) so the kill ladder can killpg a whole subtree in one call, including grandchildren the subagent forked itself. The supervisor delivers the SpawnPayload as the first control frame; the child’s upward AgentMsgs are read on a dedicated thread and forwarded — tagged with the child’s NodeId — onto the reactor’s single merged channel, which is what lets the reactor stay single-threaded no matter how many children are live.

Teardown is reap-safe: once the reactor has reaped a child via waitpid(-1) it calls Subagent::mark_reaped, so Drop will not signal a possibly-reused pid.

Structs

Subagent

A handle to a running subagent process and the down side of its control channel. Upward messages arrive on the reactor’s merged channel, not here.

Functions

spawn

Spawn a subagent that re-execs exe (normally std::env::current_exe()), delivering payload. Upward messages are handed to events tagged with node.

Type Aliases

FrameSink

Where a child’s upward frames land. The reader thread calls this for every frame, directly into the queue the consumer drains — no intermediate hop, because ordering with other producers (the reap path) is established by joining the reader, and a hop thread would break that happens-before. Return false when the consumer is gone (stops the reader).