sglang rust server tokenizer manager, ring and runtime (#32358)

rust/sglang-server/src/fsm.rs

@@ -7,10 +7,10 @@
 //!
 //! Port of the design enum:
 //! ```text
-//! Received, Validating, Normalizing, Encoding, Tokenizing, Queued,
+//! Received, Validating, Normalizing, Encoding, Tokenizing, PreSendValidating,
-//! Streaming { chunks_sent }, Finalizing, Completed, Failed(Error), Aborted
+//! Queued, Streaming { chunks_sent }, Finalizing, Completed, Failed(Error),
+//! Aborted
 //! ```
-#![allow(dead_code)] // TODO: remove when the consumer PR lands
 
 use crate::error::Error;
 
@@ -25,6 +25,10 @@ pub enum RequestState {
     Normalizing,
     Encoding,
     Tokenizing,
+    /// Every branch converges here with its final `input_ids`, for the checks
+    /// that need the tokenized length (the input + `max_new_tokens` ceiling).
+    /// The last state before the request leaves Rust.
+    PreSendValidating,
     Queued,
     Streaming {
         chunks_sent: u64,
@@ -43,7 +47,7 @@ pub enum ValidationOutcome {
     HasMultimodal,
     /// Plain text → Tokenizing.
     NeedsTokenize,
-    /// Caller already supplied token ids → straight to Queued.
+    /// Caller already supplied token ids → straight to the pre-send checks.
     AlreadyTokenized,
 }
 
@@ -57,9 +61,13 @@ pub enum Event {
     NeedsNormalize,
     EncodeDone,
     TokenizeDone,
+    /// The pre-send checks passed; the request may be pushed to the ring.
+    PreSendValidated,
     SchedulerPicked,
     // --- egress ---
-    Chunk { finish: bool },
+    Chunk {
+        finish: bool,
+    },
     FinalFrameSent,
     // --- terminal (valid from any state) ---
     Error(Error),
@@ -112,14 +120,17 @@ impl RequestState {
             // ingress
             (Received, Validated(_)) => Validating,
             // Generate requests pass through Normalizing (sampling-param
-            // normalize/verify); control requests skip straight to Queued.
+            // normalize/verify); control requests skip it, having none.
             (Validating, NeedsNormalize) => Normalizing,
-            (Validating, Validated(AlreadyTokenized)) => Queued,
+            (Validating, Validated(AlreadyTokenized)) => PreSendValidating,
             (Normalizing, Validated(HasMultimodal)) => Encoding,
             (Normalizing, Validated(NeedsTokenize)) => Tokenizing,
-            (Normalizing, Validated(AlreadyTokenized)) => Queued,
+            (Normalizing, Validated(AlreadyTokenized)) => PreSendValidating,
             (Encoding, EncodeDone) => Tokenizing,
-            (Tokenizing, TokenizeDone) => Queued,
+            // Every ingress branch funnels through the pre-send checks, so they
+            // run exactly once per request no matter how it got its ids.
+            (Tokenizing, TokenizeDone) => PreSendValidating,
+            (PreSendValidating, PreSendValidated) => Queued,
             (Queued, SchedulerPicked) => Streaming { chunks_sent: 0 },
             // egress
             (Streaming { chunks_sent }, Chunk { finish: false }) => Streaming {
@@ -133,3 +144,59 @@ impl RequestState {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn after(mut state: RequestState, event: Event) -> RequestState {
+        state.apply(event).expect("edge must exist");
+        state
+    }
+
+    /// Every ingress branch — control, client-supplied ids, and text through the
+    /// tokenizer pool — must land in `PreSendValidating`, because that is where
+    /// the checks needing the final `input_ids` run. A branch that reached
+    /// `Queued` directly would skip them silently.
+    #[test]
+    fn every_branch_reaches_the_ring_through_pre_send_validating() {
+        for from in [
+            after(
+                RequestState::Validating,
+                Event::Validated(ValidationOutcome::AlreadyTokenized),
+            ),
+            after(
+                RequestState::Normalizing,
+                Event::Validated(ValidationOutcome::AlreadyTokenized),
+            ),
+            after(RequestState::Tokenizing, Event::TokenizeDone),
+        ] {
+            assert!(
+                matches!(from, RequestState::PreSendValidating),
+                "branch bypassed the pre-send checks: {from:?}"
+            );
+            assert!(matches!(
+                after(from, Event::PreSendValidated),
+                RequestState::Queued
+            ));
+        }
+    }
+
+    /// The converse: `Queued` has no other in-edge, so the checks can't be skipped
+    /// by emitting the wrong event, and can't run twice.
+    #[test]
+    fn queued_has_no_other_in_edge() {
+        for mut state in [
+            RequestState::Validating,
+            RequestState::Normalizing,
+            RequestState::Tokenizing,
+            RequestState::Queued,
+        ] {
+            assert_eq!(
+                state.apply(Event::PreSendValidated),
+                Err(TransitionError::Illegal),
+                "only PreSendValidating may enter Queued"
+            );
+        }
+    }
+}

rust/sglang-server/src/lib.rs

@@ -16,6 +16,9 @@ mod error;
 mod fsm;
 mod ids;
 mod message;
+mod ring;
+mod runtime;
+mod tokenizer_manager;
 mod utils;
 
 use pyo3::prelude::*;

rust/sglang-server/src/message.rs

@@ -15,6 +15,65 @@ mod request;
 mod sampling;
 mod types;
 
-pub(crate) use request::GenerateRequest;
+pub use egress::{ChunkEvent, EgressSink};
+pub use request::{GenerateRequest, RequestKind};
 pub(crate) use sampling::{SamplingParams, SamplingParamsInput};
 pub(crate) use types::{OneOrMany, OneOrManyItem, TokenIds};
+
+use bytes::Bytes;
+
+use crate::fsm::RequestState;
+use crate::ids::Rid;
+
+/// The owned request as it travels ingress stages (single owner, so `state` is
+/// mutated lock-free). Common fields here; variant data in [`RequestKind`].
+#[derive(Debug)]
+pub struct Request {
+    /// Client-visible request id (uuid hex) — what the scheduler wire and
+    /// `meta_info.id` carry.
+    pub rid: Rid,
+    pub state: RequestState,
+    /// Back-channel to the client connection for egress frames.
+    pub sink: EgressSink,
+    /// Discriminant + variant body (generate vs control).
+    pub kind: RequestKind,
+}
+
+/// One ingress-ring entry, split columnar: the scalar `header` (msgpack, `input_ids`
+/// omitted) + the raw int64 `ids` cell, so the big tensor never goes through msgpack.
+#[derive(Debug)]
+pub struct IngressMsg {
+    pub header: Bytes,
+    pub ids: Bytes,
+}
+
+/// Messages to a Detokenizer shard. `Register` carries the per-request sink for
+/// the shard's local `rid -> sink` map. The rid STRING is the identity: `Rid::hash`
+/// picks the shard (collisions there merely co-locate, which is harmless), but two
+/// distinct rids that hash alike must not be the same map entry — that evicted one
+/// client's sink and delivered their tokens to the other's connection. Equal rids
+/// cannot reach here from different requests: `Rid::from_client` uniquifies every
+/// client-supplied one.
+pub enum DetokMsg {
+    Register {
+        /// Client-visible rid string — kept in `DetokState` so the shard can
+        /// emit `TmEvent::Abort(rid)` (the wire needs the string, not the hash).
+        rid: Rid,
+        sink: EgressSink,
+        /// Decode logprob token ids to text here (CPU-bound) not on the api threads.
+        decode_logprob_text: bool,
+        /// `SamplingParams.no_stop_trim`: keep the matched stop; default trims it.
+        no_stop_trim: bool,
+    },
+    /// One decode step's chunks for *this shard*. Batched because `tm-egress` blocks
+    /// per send, so one message per request cost ~1.3 µs × batch (5.1x at 4096).
+    Chunks(Vec<ChunkEvent>),
+    /// Control result: one already-serialized payload delivered to the sink verbatim.
+    Result { rid: Rid, payload: bytes::Bytes },
+    /// Terminal per-request failure → an `Error` to the sink (a 400, not a crash).
+    Fail { rid: Rid, message: String },
+    /// Drop the `rid -> sink` entry for a request rejected before the scheduler
+    /// (the rejecting stage already answered the client); else `Register` leaks one
+    /// entry.
+    Deregister { rid: Rid },
+}

rust/sglang-server/src/message/request.rs

@@ -486,6 +486,10 @@ fn fan_out<T: OneOrManyItem + Clone + HeapBytes>(
 mod tests {
     use super::*;
 
+    /// Vocab size for tests that aren't about the vocab bound (see
+    /// `sampling::tests::TEST_VOCAB`).
+    const TEST_VOCAB: u64 = 1000;
+
     fn requests(body: &str) -> Result<(Vec<GenerateRequest>, bool), Error> {
         serde_json::from_str::<GenerateBody>(body)
             .unwrap()
@@ -558,7 +562,7 @@ mod tests {
         // Parallel sampling is rejected where Python reads it — in the params,
         // at normalization (the ingress step), not here.
         let (mut ps, _) = requests(r#"{"text": "a", "sampling_params": {"n": 2}}"#).unwrap();
-        assert!(ps[0].sampling_params.normalize(false, None).is_err());
+        assert!(ps[0].sampling_params.normalize(false, TEST_VOCAB).is_err());
     }
 
     /// Unported `GenerateReqInput` fields are IGNORED, not rejected.

rust/sglang-server/src/ring.rs

@@ -0,0 +1,251 @@
+//! The two Rust↔Python boundary queues.
+//!
+//! In embedded mode the Rust frontend threads and the Python scheduler loop
+//! share one process, so these are in-process `flume` channels — literal
+//! `mpsc`/`mpmc`, no shared memory, no serialization beyond the msgpack bytes
+//! the payload already is.
+//!
+//! GIL note: the Python side only ever calls the *non-blocking* `drain` /
+//! `try_push` methods while holding the GIL, and the Rust worker threads only
+//! ever push/drain raw `Bytes` — neither side touches a `PyObject` off-thread,
+//! so the producer threads never need the GIL.
+
+use std::sync::Mutex;
+use std::time::Duration;
+
+use bytes::Bytes;
+
+use crate::message::IngressMsg;
+
+/// Ingress: TokenizerManager → scheduler `recv_requests`.
+/// Producers are Rust TM workers; the single consumer is the Python thread.
+/// Carries [`IngressMsg`] (columnar: scalar header + raw int64 ids cell), not a
+/// single msgpack blob, so the large `input_ids` tensor bypasses msgpack.
+#[derive(Clone)]
+pub struct IngressProducer {
+    tx: flume::Sender<IngressMsg>,
+}
+
+pub struct IngressConsumer {
+    rx: flume::Receiver<IngressMsg>,
+    /// One-slot buffer holding a message consumed by a blocking [`wait`] so the
+    /// scheduler can park on idle without losing it — the next [`drain`] returns
+    /// it first. Only ever touched by the single consumer (the Python thread),
+    /// so contention is nil; the `Mutex` is just for interior mutability across
+    /// the `&self` methods.
+    ///
+    /// [`wait`]: IngressConsumer::wait
+    /// [`drain`]: IngressConsumer::drain
+    stash: Mutex<Option<IngressMsg>>,
+}
+
+/// A drained ingress batch in **columnar** (struct-of-arrays) form. The `ids`
+/// cells are kept *un-concatenated* so the pyo3 boundary can copy them straight
+/// into one `PyBytes` (no intermediate buffer); `ids_total` is their summed
+/// length, precomputed for that single allocation.
+#[derive(Default)]
+pub struct IngressColumns {
+    /// Per-request scalar msgpack header (`input_ids` omitted).
+    pub headers: Vec<Bytes>,
+    /// Per-request raw little-endian int64 ids cell (empty for control reqs).
+    pub ids: Vec<Bytes>,
+    /// Per-request token count (`ids` cell length / 8).
+    pub lengths: Vec<u32>,
+    /// Sum of all `ids` cell byte lengths.
+    pub ids_total: usize,
+}
+
+impl IngressProducer {
+    /// Non-blocking push. Returns `false` on a full ring (backpressure) so the
+    /// caller can fail the request rather than block a worker thread.
+    #[inline]
+    pub fn try_push(&self, msg: IngressMsg) -> bool {
+        self.tx.try_send(msg).is_ok()
+    }
+}
+
+impl IngressConsumer {
+    /// Drain up to `max` messages into a columnar [`IngressColumns`], returning
+    /// immediately when the ring runs dry — mirrors the scheduler's existing
+    /// `zmq.NOBLOCK` loop in `request_receiver._pull_raw_reqs`. Splitting headers
+    /// from ids here (off the GIL) leaves `recv_requests` a thin marshaling shim.
+    ///
+    /// Non-blocking by construction: `try_recv` returns `Err(TryRecvError::Empty)`
+    /// instantly when the ring is empty, and `Err(_) => break` exits the loop
+    /// right away.
+    pub fn drain(&self, max: usize) -> IngressColumns {
+        let mut batch = IngressColumns::default();
+        // A message parked by a prior blocking `wait` is delivered first.
+        if let Some(m) = self.stash.lock().unwrap().take() {
+            push_msg(&mut batch, m);
+        }
+        while batch.headers.len() < max {
+            match self.rx.try_recv() {
+                Ok(m) => push_msg(&mut batch, m),
+                Err(_) => break, // Empty or Disconnected -> stop now
+            }
+        }
+        batch
+    }
+
+    /// Park up to `timeout` for at least one incoming message, so the idle
+    /// scheduler loop sleeps instead of spinning at 100% CPU. The message is
+    /// **stashed, not returned** — the next [`drain`](Self::drain) yields it —
+    /// so this composes with the existing non-blocking drain flow. Returns
+    /// whether a message is now available. `flume` wakes the parked thread the
+    /// instant a producer pushes, so this adds no latency to real requests.
+    pub fn wait(&self, timeout: Duration) -> bool {
+        if self.stash.lock().unwrap().is_some() {
+            return true;
+        }
+        match self.rx.recv_timeout(timeout) {
+            Ok(m) => {
+                *self.stash.lock().unwrap() = Some(m);
+                true
+            }
+            Err(_) => false, // Timeout or Disconnected
+        }
+    }
+}
+
+/// Append one drained message's columnar cells to the batch.
+#[inline]
+fn push_msg(batch: &mut IngressColumns, m: IngressMsg) {
+    batch.ids_total += m.ids.len();
+    batch.lengths.push((m.ids.len() / 8) as u32); // int64 cell → tokens
+    batch.headers.push(m.header);
+    batch.ids.push(m.ids);
+}
+
+/// Egress: scheduler output (`push_chunk`) → Rust egress dispatcher.
+/// The single producer is the Python thread; the consumer is the dispatcher.
+#[derive(Clone)]
+pub struct EgressProducer {
+    tx: flume::Sender<Bytes>,
+}
+
+pub struct EgressConsumer {
+    rx: flume::Receiver<Bytes>,
+}
+
+impl EgressProducer {
+    /// Blocking push: parks until the ring has space, so a full ring applies
+    /// backpressure to the scheduler instead of dropping output the scheduler has
+    /// already committed (advanced `send_token_offset` for). The GIL is released
+    /// around the call, so parking here doesn't stall other Python threads.
+    /// `false` only when the consumer is gone (runtime shutdown), where the frame
+    /// is unavoidably lost.
+    pub fn push(&self, msg: Bytes) -> bool {
+        self.tx.send(msg).is_ok()
+    }
+
+    /// Non-blocking push, so the pyo3 boundary can try to hand the frame over
+    /// while still holding the GIL and detach only when it would actually park.
+    /// Releasing the GIL is not free: reacquiring it waits out the interpreter's
+    /// switch interval (5 ms by default), which dwarfs the sub-microsecond push
+    /// it was protecting.
+    ///
+    /// Hands the frame BACK on a full ring (`Err(Some(msg))`) so the caller can
+    /// retry it under [`push`](Self::push) without rebuilding it. `Err(None)` is
+    /// the consumer being gone (shutdown), where the frame is unavoidably lost.
+    #[inline]
+    pub fn try_push(&self, msg: Bytes) -> Result<(), Option<Bytes>> {
+        match self.tx.try_send(msg) {
+            Ok(()) => Ok(()),
+            Err(flume::TrySendError::Full(msg)) => Err(Some(msg)),
+            Err(flume::TrySendError::Disconnected(_)) => Err(None),
+        }
+    }
+}
+
+impl EgressConsumer {
+    /// The underlying receiver, so the dispatcher can drain it via
+    /// [`tokenizer_manager::recv`](crate::tokenizer_manager::recv) (data + shutdown select).
+    pub fn receiver(&self) -> &flume::Receiver<Bytes> {
+        &self.rx
+    }
+}
+
+/// Build both halves of a bounded ring.
+pub fn ingress_ring(cap: usize) -> (IngressProducer, IngressConsumer) {
+    let (tx, rx) = flume::bounded(cap);
+    (
+        IngressProducer { tx },
+        IngressConsumer {
+            rx,
+            stash: Mutex::new(None),
+        },
+    )
+}
+
+pub fn egress_ring(cap: usize) -> (EgressProducer, EgressConsumer) {
+    let (tx, rx) = flume::bounded(cap);
+    (EgressProducer { tx }, EgressConsumer { rx })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn msg(h: &'static [u8]) -> IngressMsg {
+        IngressMsg {
+            header: Bytes::from_static(h),
+            ids: Bytes::new(),
+        }
+    }
+
+    /// `wait` parks when empty (times out), stashes a pushed message
+    /// non-destructively, and the next `drain` returns it.
+    #[test]
+    fn wait_stashes_then_drain_returns_it() {
+        let (tx, rx) = ingress_ring(8);
+        // Empty ring → times out, nothing stashed.
+        assert!(!rx.wait(Duration::from_millis(1)));
+        // Push one, then wait stashes it (returns true).
+        assert!(tx.try_push(msg(b"a")));
+        assert!(rx.wait(Duration::from_millis(200)));
+        // Idempotent: already stashed, returns true without touching the ring.
+        assert!(rx.wait(Duration::from_millis(1)));
+        // Drain yields the stashed message, then the ring is empty.
+        assert_eq!(rx.drain(16).headers.len(), 1);
+        assert!(rx.drain(16).headers.is_empty());
+    }
+
+    /// A blocked `wait` is woken the instant a producer pushes (no polling).
+    #[test]
+    fn wait_wakes_on_push() {
+        let (tx, rx) = ingress_ring(8);
+        std::thread::spawn(move || {
+            std::thread::sleep(Duration::from_millis(20));
+            let _ = tx.try_push(msg(b"a"));
+        });
+        // Generous timeout, but it should return well before it as soon as the
+        // push lands.
+        assert!(rx.wait(Duration::from_secs(5)));
+        assert_eq!(rx.drain(16).headers.len(), 1);
+    }
+
+    /// A full egress ring parks the producer until the consumer drains — the
+    /// committed frame is delivered in order, never dropped.
+    #[test]
+    fn egress_push_blocks_until_drained() {
+        let (tx, rx) = egress_ring(1);
+        assert!(tx.push(Bytes::from_static(b"a"))); // fits; ring now full
+        let t = std::thread::spawn(move || tx.push(Bytes::from_static(b"b")));
+        // The parked push can't have completed while the ring is full.
+        std::thread::sleep(Duration::from_millis(20));
+        // Drain one → frees a slot → the parked push lands.
+        assert_eq!(rx.receiver().recv().unwrap(), Bytes::from_static(b"a"));
+        assert!(t.join().unwrap(), "push should succeed once space frees");
+        assert_eq!(rx.receiver().recv().unwrap(), Bytes::from_static(b"b"));
+    }
+
+    /// A closed ring (consumer gone → shutdown) returns `false` instead of
+    /// parking forever, so a scheduler blocked in `push` unblocks on teardown.
+    #[test]
+    fn egress_push_returns_false_when_closed() {
+        let (tx, rx) = egress_ring(1);
+        drop(rx);
+        assert!(!tx.push(Bytes::from_static(b"x")));
+    }
+}

rust/sglang-server/src/runtime.rs

@@ -0,0 +1,18 @@
+//! Runtime bootstrap: wires channels, pins CPU-bound pools, starts the tokio
+//! API server, and returns a handle the Python boundary uses for
+//! `recv_requests` (ingress drain) and `push_batch` (egress push).
+//!
+//! Thread layout:
+//!   * API server   — tokio multi-thread runtime (I/O bound), pinned core set A
+//!   * Tokenizer    — N pinned OS threads (CPU bound), core set B
+//!   * Detokenizer  — M pinned OS threads / shards (CPU bound), core set C
+//!   * TM ingress   — 1 thread driving the ingress FSM
+//!   * TM egress    — 1 thread draining the egress ring → detok shards
+//!
+//! Keeping CPU-bound tokenize/detokenize off the async executor avoids stalling
+//! axum's worker threads.
+
+mod config;
+mod runnable;
+
+// Re-export so stages keep importing `crate::runtime::Runnable`.

rust/sglang-server/src/runtime/config.rs

@@ -0,0 +1,203 @@
+//! Runtime configuration: the rust-server boot knobs
+//! ([`RustServerServerArgs`]), the typed view of the scheduler's `server_args`
+//! dump ([`ServerArgs`] / [`ModelConfig`]), and the [`RuntimeConfig`] pairing
+//! them for `runtime::start`.
+
+use std::net::SocketAddr;
+use std::sync::Arc;
+
+/// Boot knobs specific to the embedded rust server — none of these exist in
+/// the Python `server_args` dump (see [`ServerArgs`]); they arrive as explicit
+/// `Server::start` parameters.
+#[derive(Clone, Debug)]
+pub struct RustServerServerArgs {
+    pub http_addr: SocketAddr,
+    pub api_worker_num: usize,
+    pub ingress_ring_cap: usize,
+    pub egress_ring_cap: usize,
+    pub channel_cap: usize,
+    /// CPU core ids the pools pin to (e.g. this rank's NUMA-local cores minus
+    /// the scheduler's reserved launch cores). `None` → run unpinned.
+    pub cores: Option<Vec<usize>>,
+}
+
+impl Default for RustServerServerArgs {
+    fn default() -> Self {
+        Self {
+            http_addr: "127.0.0.1:30000".parse().unwrap(),
+            api_worker_num: 2,
+            ingress_ring_cap: 8192,
+            egress_ring_cap: 8192,
+            channel_cap: 8192,
+            cores: None,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct RuntimeConfig {
+    /// Rust-server-only boot knobs (listen address, pool/ring sizes, pinning).
+    pub rust_server_args: RustServerServerArgs,
+    /// The scheduler's `server_args` dump (worker counts, tokenizer source,
+    /// config-endpoint metadata). `Arc` so cloning the config (and, downstream,
+    /// each `AppState`) is cheap; immutable after construction.
+    pub server_args: Arc<ServerArgs>,
+}
+
+impl Default for RuntimeConfig {
+    fn default() -> Self {
+        Self {
+            rust_server_args: RustServerServerArgs::default(),
+            server_args: Arc::new(
+                ServerArgs::from_json("{}").expect("empty server_args blob parses"),
+            ),
+        }
+    }
+}
+
+/// The scheduler's startup blob (`RustServer._build_server_args`) parsed once into
+/// typed fields: values are post-`__post_init__`, unknown keys (e.g. `api_key`) are dropped.
+#[derive(Debug, serde::Deserialize)]
+pub struct ServerArgs {
+    /// HF repo id / local dir of the model, reported by `/get_model_info`.
+    #[serde(default)]
+    pub model_path: String,
+    /// Model name reported by `/v1/models` and `/server_info`.
+    #[serde(default)]
+    pub served_model_name: String,
+    /// Tokenizer source (model dir / `tokenizer.json` / HF repo id). Empty only
+    /// in minimal standalone blobs — then boot requires `skip_tokenizer_init`.
+    #[serde(default)]
+    pub tokenizer_path: String,
+    /// HF revision, used only when `tokenizer_path` is a repo id. `None` → main.
+    #[serde(default)]
+    pub revision: Option<String>,
+    /// HTTP bind address (see [`Self::bind`]).
+    #[serde(default = "default_host")]
+    pub host: String,
+    #[serde(default = "default_port")]
+    pub port: u16,
+    /// Log levels driving the access log — uvicorn runs at
+    /// `log_level_http or log_level` (see [`Self::http_access_log_enabled`]).
+    #[serde(default = "default_log_level")]
+    pub log_level: String,
+    #[serde(default)]
+    pub log_level_http: Option<String>,
+    /// Pinned tokenizer threads / detok shards (Python asserts both ≥ 1).
+    #[serde(default = "default_worker_num")]
+    pub tokenizer_worker_num: usize,
+    #[serde(default = "default_worker_num")]
+    pub detokenizer_worker_num: usize,
+    /// Token-ids-in / token-ids-out mode: no tokenizer load, raw `output_ids`
+    /// frames (drives the `Skip` detok backend and the ingress branch).
+    #[serde(default)]
+    pub skip_tokenizer_init: bool,
+    /// Streamed `/generate` frames carry per-step deltas instead of cumulative
+    /// text. Matches the Python `TokenizerManager`.
+    #[serde(default)]
+    pub incremental_streaming_output: bool,
+    /// The resolved Python `ModelConfig`, attached to the blob at dump time.
+    #[serde(default)]
+    pub model_config: ModelConfig,
+    /// Default sampling params advertised by `/get_model_info`, verbatim from
+    /// `server_args.preferred_sampling_params` (a JSON object or null).
+    #[serde(default)]
+    pub preferred_sampling_params: Option<serde_json::Value>,
+    /// Over-long inputs are truncated to fit the context instead of 400ing, and
+    /// `max_new_tokens` is clamped rather than rejected (Python
+    /// `TokenizerManager._validate_one_request`).
+    #[serde(default)]
+    pub allow_auto_truncate: bool,
+    /// `return_hidden_states` is refused unless the server was launched with it:
+    /// the scheduler simply won't produce them, so the request would 200 with the
+    /// field silently missing.
+    #[serde(default)]
+    pub enable_return_hidden_states: bool,
+    /// Output slots reserved per request on top of its input (eagle stores draft
+    /// tokens there). Not a `server_args` field — `TokenizerManager` derives it and
+    /// `RustServer._build_server_args` stamps it in, so both sides count alike.
+    #[serde(default)]
+    pub num_reserved_tokens: u64,
+    /// Launch-time stamps (not `server_args` fields): sglang package version
+    /// and the scheduler-derived KV token capacity, reported by `/server_info`.
+    #[serde(default)]
+    pub version: Option<String>,
+    #[serde(default)]
+    pub max_total_num_tokens: Option<u64>,
+}
+
+/// The slice of the resolved Python `ModelConfig` the rust server reads.
+#[derive(Debug, Default, serde::Deserialize)]
+pub struct ModelConfig {
+    /// Resolved context length (`max_model_len` in `/v1/models`); mandatory at
+    /// boot ([`ServerArgs::validate_mandatory`]).
+    #[serde(default)]
+    pub context_len: Option<u64>,
+    /// Bounds client-supplied token ids — ingress 400s out-of-vocab ids before
+    /// they crash the scheduler's embedding lookup;  mandatory at
+    /// boot ([`ServerArgs::validate_mandatory`]).
+    #[serde(default)]
+    pub vocab_size: Option<u64>,
+}
+
+fn default_host() -> String {
+    "127.0.0.1".into()
+}
+fn default_port() -> u16 {
+    30000
+}
+fn default_log_level() -> String {
+    "info".into()
+}
+fn default_worker_num() -> usize {
+    1
+}
+
+impl ServerArgs {
+    /// Parse the blob; errors on malformed JSON or a wrongly-typed field.
+    pub fn from_json(s: &str) -> Result<Self, String> {
+        serde_json::from_str(s).map_err(|e| e.to_string())
+    }
+
+    /// Fail fast at startup if a field an endpoint depends on is missing.
+    pub fn validate_mandatory(&self) -> Result<(), String> {
+        if self.served_model_name.is_empty() {
+            return Err("no 'served_model_name' in server_args".into());
+        }
+        if self.model_config.context_len.is_none() {
+            return Err("no resolvable context length (model_config.context_len)".into());
+        }
+        if self.model_config.vocab_size.is_none() {
+            return Err("no resolvable vocab size (model_config.vocab_size)".into());
+        }
+        Ok(())
+    }
+
+    /// Bind address `host:port`. `host` is expected to be an IP — the result is
+    /// parsed as a `SocketAddr`.
+    pub fn bind(&self) -> String {
+        format!("{}:{}", self.host, self.port)
+    }
+
+    /// Whether the HTTP access log is emitted, mirroring the Python server:
+    /// uvicorn runs at `log_level_http or log_level` and prints access lines
+    /// only at info/debug. `--log-level-http warning` turns them off.
+    pub fn http_access_log_enabled(&self) -> bool {
+        let level = self
+            .log_level_http
+            .as_deref()
+            .filter(|s| !s.is_empty())
+            .unwrap_or(&self.log_level);
+        matches!(
+            level.to_ascii_lowercase().as_str(),
+            "trace" | "debug" | "info"
+        )
+    }
+
+    /// Pinned API threads for the embedded HTTP api-server. Python `server_args`
+    /// has no such field — this is derived: enough to cover the widest pool.
+    pub fn api_worker_num(&self) -> usize {
+        4.max(self.tokenizer_worker_num)
+            .max(self.detokenizer_worker_num)
+    }
+}

rust/sglang-server/src/runtime/runnable.rs

@@ -0,0 +1,10 @@
+//! The [`Runnable`] stage trait — the one contract every pipeline stage
+//! (CPU-bound worker or TM router) implements to be spawned by the runtime.
+
+/// A pipeline stage that owns its channel handles + config and runs a blocking
+/// loop until its inbox closes. Lets the runtime spawn stages uniformly via
+/// `threads::spawn_stage` / `threads::spawn_pool` instead of free `run_*` functions with
+/// positional handles. Implemented by every CPU-bound worker and TM router.
+pub trait Runnable: Send + 'static {
+    fn run(self);
+}

rust/sglang-server/src/tokenizer_manager.rs

@@ -0,0 +1,87 @@
+//! TokenizerManager — owns the request lifecycle across two isolated threads:
+//!
+//!   * [`ingress`] — drives the ingress FSM (Received → Validating →
+//!     Normalizing → {Tokenizing | PreSendValidating}) and pushes tokenized requests to the
+//!     scheduler ring.
+//!   * [`egress`] — drains the scheduler-output ring and routes each chunk to
+//!     the owning detokenizer shard.
+//!
+//! The two run on separate pinned threads with no shared state, connected to
+//! the rest of the pipeline only through `flume` channels: [`TmEvent`] into the
+//! ingress loop, [`Senders`] fanning out to the pools.
+
+use crate::ids::Rid;
+use crate::message::{DetokMsg, Request};
+
+/// Blocking receive that also wakes on shutdown: returns `None` when `rx` closes
+/// *or* the `shutdown` sender is dropped.
+pub fn recv<T>(rx: &flume::Receiver<T>, shutdown: &flume::Receiver<()>) -> Option<T> {
+    flume::Selector::new()
+        .recv(rx, |r| r.ok())
+        .recv(shutdown, |_| None)
+        .wait()
+}
+
+/// Events into the TokenizerManager ingress loop. API server + tokenizer pool
+/// share this one inbox, keeping the loop a single consumer (no `select`).
+pub enum TmEvent {
+    /// A freshly received request from the API server.
+    Ingress(Request),
+    /// A request back from the tokenizer pool: `PreSendValidating` (ids filled) on success,
+    /// or `Failed` on a tokenize error. `drive` handles both.
+    Tokenized(Request),
+}
+
+/// Producer-side handles, cloned into every stage that needs to emit.
+/// Who asked for an abort. Both variants do the same work in
+/// [`Ingress::on_abort`](crate::tokenizer_manager::ingress::Ingress) — deregister
+/// the detok entry, tell the scheduler to stop — and the source is kept for
+/// diagnostics.
+///
+/// There is no in-flight rid registry to keep consistent, and so no release
+/// ordering to get wrong: [`Rid::from_client`] makes every client-supplied rid
+/// internally unique, so a resubmit of the "same" rid is a different `Rid` and
+/// cannot be tangled up with an abort still in flight for the original.
+#[derive(Clone, Debug)]
+pub enum AbortSource {
+    /// From an `AbortGuard` drop. Owns the release.
+    Guard(Rid),
+    /// From a detokenizer terminal path. Aborts the scheduler work.
+    Detok(Rid),
+}
+
+impl AbortSource {
+    pub fn rid(&self) -> &Rid {
+        match self {
+            Self::Guard(rid) | Self::Detok(rid) => rid,
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct Senders {
+    /// → TokenizerManager ingress loop.
+    pub tm: flume::Sender<TmEvent>,
+    /// → the same loop, but UNBOUNDED and abort-only.
+    ///
+    /// Aborts cannot share the bounded inbox. `try_send` there drops them exactly
+    /// when they matter most — under overload — leaving the scheduler generating
+    /// for a dead connection; and the caller then faces a false choice between
+    /// releasing the rid (a live entry can be overwritten by a resubmit) and
+    /// holding it (a permanent leak). An unbounded lane removes the dilemma: an
+    /// abort is a small `String` and is always accepted, so releases can be
+    /// unconditional again. It cannot grow without bound in practice — one entry
+    /// per in-flight request, each already bounded by the inbox that admitted it.
+    pub abort: flume::Sender<AbortSource>,
+    /// → Tokenizer pool (CPU-bound, pinned threads).
+    pub tok: flume::Sender<Request>,
+    /// → Detokenizer shards, indexed by `Rid::shard(detok.len())`.
+    pub detok: Vec<flume::Sender<DetokMsg>>,
+}
+
+impl Senders {
+    #[inline]
+    pub fn detok_for(&self, rid: &Rid) -> &flume::Sender<DetokMsg> {
+        &self.detok[rid.shard(self.detok.len())]
+    }
+}