shoney.arickathil
ab8ef64cd9
- five stories under docs/stories/runtime-v2/: 1 streaming subprocess (42's follow-up; five forks incl. the mailbox-cap collision), 2 PTY, 3 signals-as-events (signalfd lean), 4 termios adoption, 5 SCM_RIGHTS fd passing; 00-story states the arc — the plane learned sockets in 8/11/35, files in 6, this adds processes/terminals/signals - build order 1 -> 2 -> 3; 4 and 5 startable alone; all readiness: refine, brainstormed on demand - board: Five tracks; "▸ runtime-v2" pending section; wmux section now points at it; graph section 6 nodes carry runtime-v2 numbers + links - wmux stories re-reference the track; prefix `rt2` claimed - linkcheck: 0 broken Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> (cherry picked from commit e0451cb4889bb3d03429c0276d03c090269a5ced)
69 lines
3.4 KiB
Markdown
69 lines
3.4 KiB
Markdown
---
|
|
track: runtime-v2
|
|
iteration: "1"
|
|
status: pending
|
|
readiness: refine
|
|
---
|
|
|
|
# runtime-v2 1 — streaming subprocess: a long-lived child as a peer
|
|
|
|
> Part of [Story — runtime-v2: the runtime beyond sockets](00-story.md).
|
|
> Iteration [42](../language-runtime-database/42-bounded-subprocess.md)'s
|
|
> named follow-up, promoted to this track's opening slice. 42 built the
|
|
> machinery a streaming form reuses whole: the `wo_child` registry, the
|
|
> pidfd wait, the epoll bundle, the cap/refusal doctrine, the ownership
|
|
> sweeps (`fib_reap`/`wo_vm_destroy`/stop).
|
|
>
|
|
> **The problem.** `proc.run`/`proc.run_dl` are one-shot: nothing can
|
|
> talk to a child while it runs, and a child that legitimately runs for
|
|
> hours (a shell under wmux, a browser under the CDP driver, a script
|
|
> under skillhost) has no shape at all. Output must reach the owning
|
|
> actor as it happens, stdin must reach the child, and exit must arrive
|
|
> as an event — all without violating a single 42 guarantee.
|
|
|
|
## Info — the forks (open; why this is `refine`)
|
|
|
|
1. **Verb shape.** A new `proc.spawn(cmd, args, …)` returning a child
|
|
HANDLE, versus spawn-options on `proc.run_dl`. Sub-fork: the handle
|
|
as an actor address (the child looks like an actor — `send` to feed
|
|
stdin, `monitor` for exit, iteration 24 machinery free) versus an
|
|
opaque scalar with its own verb family.
|
|
2. **Output transport.** PUSH — stdout/stderr chunks delivered as
|
|
`Bytes` messages into the owner's mailbox (the fd-event pattern) —
|
|
versus PULL — a `read`-style verb the fiber parks on, the
|
|
`net.read_dl` mould. Push composes with actors; pull composes with
|
|
backpressure.
|
|
3. **The mailbox-cap collision** — the fork that decides whether push is
|
|
viable at all: a chatty child versus `wo_mailbox_cap`'s fail-fast
|
|
1024. Drop chunks? Kill the child by name? Or stop reading the pipe
|
|
and let the KERNEL buffer be the backpressure (the lean — the child
|
|
blocks on a full pipe exactly as it would under a slow tmux).
|
|
4. **stdin and its mirror.** Child not reading, pipe full: park the
|
|
writing fiber with a deadline (the `net.write_dl` mould) versus
|
|
refuse at a byte cap.
|
|
5. **Bounds semantics shift.** Total-output cap and total deadline stop
|
|
meaning anything for a shell that runs for days — per-chunk caps and
|
|
an IDLE deadline replace them; exit notification as a monitor-style
|
|
death notice carrying the code, versus a blocking `wait` verb.
|
|
|
|
Ownership does not fork: 42's rule stands — the owner unwinding kills
|
|
the child; engine stop kills them all; a zombie or an orphan is a bug.
|
|
|
|
## Acceptance sketch (firmed at brainstorm)
|
|
|
|
- A child that emits a line a second: each line reaches the owning
|
|
actor while the child lives — not after it exits.
|
|
- stdin round trip: feed a `cat`-like child, read the echo back.
|
|
- The chatty child against whatever fork 3 picked: the declared
|
|
behavior happens, by name, and the shard never stalls.
|
|
- Exit: the owner learns the code as an event; the registry slot is
|
|
released; fd count flat (the 42 measurement legs, streaming edition).
|
|
- Stop/unwind: identical guarantees to 42, proven with a LIVE stream.
|
|
- Gate legs land in `runtime/test/test_proc.c` beside 42's.
|
|
|
|
## Consumers
|
|
|
|
wmux 1 (the shell under every pane), skillhost 28 (stdin/stdout
|
|
transport was half its named gap), the zen study's CDP driver (spawn the
|
|
browser, then talk to it). The alacritty stage-A "headless PTY runner"
|
|
is this plus [runtime-v2 2](02-pty.md).
|