vane_core/
flow_ctx.rs

1use std::sync::Arc;
2
3use tokio_util::sync::CancellationToken;
4
5use crate::flow_log::{FlowLogSink, FlowLogVerbosity, TrajectoryBuilder};
6
7/// Per-walk execution context. Constructed once per L4 connection (and
8/// re-constructed per L7 request when a hyper service-fn dispatches into
9/// the L7 sub-graph). Fields are *owned* — no lifetime parameter — so the
10/// struct survives `tokio::spawn` and `move` closures (notably hyper's
11/// service-fn closure at `Node::Upgrade`, which captures `log` / `cancel`
12/// / `verbosity` per request).
13///
14/// `Arc<dyn FlowLogSink>` and `CancellationToken` clone cheaply (each is
15/// internally an `Arc`), and `tracing::Span` is also `Arc`-backed; the
16/// per-request clones in the hyper bridge are O(1).
17pub struct FlowCtx {
18	pub span: tracing::Span,
19	pub log: Arc<dyn FlowLogSink>,
20	/// Hard-cancel token. Fired by the listener's `force_cancel` tier
21	/// when shutdown's soft-drain window expires. Long-lived
22	/// terminators (`ByteTunnel`, UDP tunnel) `select!` on this and
23	/// surface `CloseReason::Cancelled`. Per-request hyper drivers
24	/// hand this to their per-request executor wiring.
25	pub cancel: CancellationToken,
26	/// Soft-drain token. Fired by the listener's `accept_cancel` tier
27	/// at the start of shutdown / listener removal — well before
28	/// `cancel` (`force_cancel`) trips. Hyper H1 / H2 drivers wire
29	/// this into `graceful_shutdown()` so idle keep-alive clients see
30	/// `Connection: close` (H1) or `GOAWAY` (H2) immediately rather
31	/// than camping until the drain budget runs out. Defaults to a
32	/// fresh detached `CancellationToken` so call sites that have not
33	/// been wired through yet keep their pre-split semantics.
34	pub accept_cancel: CancellationToken,
35	/// Verbosity selected when this connection was accepted. The listener
36	/// reads `engine::VerbosityState` once at `FlowCtx` construction;
37	/// in-flight connections retain the value they were built with.
38	pub verbosity: FlowLogVerbosity,
39	/// Walker-internal step accumulator. The executor pushes one entry
40	/// per node-visit and emits a single `FlowLogKind::Trajectory` event
41	/// from `finalize()` at terminate or error.
42	pub trajectory: TrajectoryBuilder,
43}
44
45#[cfg(test)]
46mod tests {
47	use parking_lot::Mutex;
48
49	use super::*;
50	use crate::conn_context::ConnId;
51	use crate::flow_log::FlowLogEvent;
52	use crate::ir::NodeId;
53
54	struct NullSink {
55		count: Mutex<u32>,
56	}
57
58	impl FlowLogSink for NullSink {
59		fn emit(&self, _event: FlowLogEvent) {
60			*self.count.lock() += 1;
61		}
62	}
63
64	// Compile-gate: a FlowCtx must be constructible from a concrete sink
65	// wrapped in `Arc<dyn FlowLogSink>`, alongside an owned tracing::Span
66	// and CancellationToken, plus the verbosity / trajectory fields the
67	// walker reads. Field visibility regressions break this.
68	#[test]
69	fn flow_ctx_accepts_arc_dyn_sink_and_owned_fields() {
70		let sink: Arc<dyn FlowLogSink> = Arc::new(NullSink { count: Mutex::new(0) });
71		let span = tracing::Span::none();
72		let cancel = CancellationToken::new();
73		let ctx = FlowCtx {
74			span,
75			log: sink,
76			cancel,
77			accept_cancel: CancellationToken::new(),
78			verbosity: FlowLogVerbosity::Trajectory,
79			trajectory: TrajectoryBuilder::new(ConnId(0), NodeId::new(0), 0),
80		};
81		let _ = &ctx.span;
82		let _ = &ctx.log;
83		let _ = &ctx.cancel;
84		let _ = &ctx.accept_cancel;
85		let _ = &ctx.verbosity;
86		let _ = &ctx.trajectory;
87	}
88}
vane_core/flow_ctx.rs

vane_core/
flow_ctx.rs
