Claude
8f0da2a806
smarm 0.7 (415effb, "lifetime is the actor's — refs are addresses") removed the
rule these three actors were built on: a GenServerRef no longer owns the server,
the loop holds its own inbox sender, and the inbox never closes when the last ref
drops. urus's pubsub table, channel hub bus and session registries were still
governed by that deleted rule — PubSub::new() spawned the table and the handle
owned its life — so nothing commanded them to stop. What still terminated a run
was the root-exit sweep, racing the drain: shutdown_with_open_chat_terminates and
channels_wire::shutdown_with_open_channel_terminates failed 4 times in 25
--all-features runs with "serve did not return: ... outlived the drain: Timeout".
Zero in 10 full-suite runs after this change.
The fix is not a supervisor wrapped around the old shape. Every gotcha in this
area descended from constructors that spawn: PubSub::new(), ChannelHub::new() and
PrefixRouter::channel_session() all started actors, which forced in-runtime-only
construction, which forced the Arc<OnceLock<..>> lazy-init from the first handler,
which forced the "cell must not be static" and "a relay must never hold a PubSub
clone" rules. Five documented rules propping up one inverted dependency. So:
description is separated from instantiation.
- PubSub<M> is a name, not a GenServerRef: const-constructible, Copy, spawns
nothing, valid outside the runtime and in a static. Operations resolve through
the registry per call, so a table restarted by its supervisor is reached
transparently (one lookup per broadcast — bench before caching a ref, which
would go stale across exactly the restart the supervisor exists to perform).
PubSub::new() is gone; PubSub::new(name) + PubSub::child() replace it.
- ChannelHub::new(bus, router) returns (hub, Vec<ChildSpec>) — the bus table plus
one registry per session route. Returning both is the point: a hub whose
children were never started compiles and fails on the first join, so the vec is
not left behind a method you can forget to call. #[must_use].
- channel_session gains a registry name; each session registry is separately
named and separately supervised.
- serve_with/serve_with_shutdown take a Vec<ChildSpec> of app children and build
the root as RestForOne[..app children, endpoint]. They start before the
endpoint and, shutdown being ordered in reverse, stop after it has drained, so
a request still in flight can reach the bus. RestForOne because a bus crash
leaves live sockets addressing a table that no longer knows them.
- Deleted: the Arc<OnceLock> idiom from both examples and both test pipelines,
and the module rules that existed only to hand-manage a refcount.
Known cost, not fixed here: channel_session("session:*", "chat-sessions", f) puts
two unrelated string literals side by side and nothing catches a transposition —
a RegistryName newtype is the obvious follow-up.
Tests: 111 lib + 50 integration + 2 doc green, clippy clean, 10/10 full-suite
runs. Unit tests poll for name binding before use — smarm's start-order-is-not-
start-readiness gap; real apps don't hit it, since a handler only runs once a
connection has been accepted.
54 lines
2.3 KiB
Rust
54 lines
2.3 KiB
Rust
//! Plain benchmark server: the `load_profile` request path with zero causal
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//! machinery — the baseline half of the ka/close A/B matrix (the
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//! throughput-inversion chase).
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//!
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//! Identical route, handler, and `Config` construction to `load_profile`;
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//! differs only in having no `smarm-causal` feature, no sweep, and no
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//! shutdown path — it serves until killed. Throughput is measured
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//! externally (wrk).
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//!
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//! Env:
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//! URUS_PORT listen port (default 8080; binds 0.0.0.0)
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//! URUS_SCHED_THREADS smarm scheduler OS threads (default: smarm's own
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//! default). Malformed values panic rather than
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//! silently falling back — a benchmark knob that
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//! quietly reverts to default poisons the cell.
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//!
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//! cargo run --release --example plain_serve
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use std::net::SocketAddr;
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use urus::{serve_with, Config, Conn, Next, Pipeline, Router};
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/// Mirrors `load_profile`'s handler byte for byte: param parse + JSON render.
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fn json_id(conn: Conn, _next: Next) -> Conn {
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let id: u64 = conn.params.get("id").and_then(|s| s.parse().ok()).unwrap_or(0);
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conn.put_status(200)
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.put_header("content-type", "application/json")
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.put_body(format!("{{\"id\":{id}}}"))
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}
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fn main() {
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let port: u16 = std::env::var("URUS_PORT")
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.ok()
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.and_then(|v| v.parse().ok())
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.unwrap_or(8080);
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let addr: SocketAddr = format!("0.0.0.0:{port}").parse().expect("addr");
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let sched_threads: Option<usize> = std::env::var("URUS_SCHED_THREADS").ok().map(|v| {
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v.parse()
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.unwrap_or_else(|_| panic!("URUS_SCHED_THREADS not a usize: {v:?}"))
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});
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// Audit line: lands in each bench cell's server.log so the effective
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// scheduler count is recorded per cell, same discipline as mode-verify.
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eprintln!("plain_serve: scheduler_threads={sched_threads:?}");
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// Scheduler threads are a RUNTIME knob, so they live in smarm::Config,
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// not urus's — an endpoint placed in someone else's tree could not
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// honour them anyway.
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let rt_cfg = match sched_threads {
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Some(n) => smarm::Config::exact(n),
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None => smarm::Config::default(),
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};
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let pipe = Pipeline::new().plug(Router::new().get("/json/:id", json_id));
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serve_with(Config::new(addr), rt_cfg, pipe, Vec::new()).expect("serve");
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}
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