feat(helper): distinguish current participant visibility

cai

2026-08-12 4c14ddfeb8964d09b83f14ce7629e42863fa67ce

 src/service.rs

@@ -4,7 +4,7 @@
    io::{BufRead, BufReader, Read, Write},
    net::{TcpListener, TcpStream},
    process::{Child, Command, Stdio},
    sync::{Arc, Mutex},
    sync::{Arc, Mutex, mpsc},
    thread,
    time::{Duration, SystemTime, UNIX_EPOCH},
};
@@ -17,6 +17,8 @@
const DEFAULT_BIND_ADDR: &str = "127.0.0.1:18080";
const HTTP_READ_LIMIT_BYTES: usize = 1024 * 1024;
const DEFAULT_START_READY_TIMEOUT_MS: u64 = 10_000;
const ANCHORED_CALLBACK_MAX_ATTEMPTS: u32 = 3;
const ANCHORED_CALLBACK_RETRY_DELAY: Duration = Duration::from_millis(50);

pub fn service_mode_enabled() -> bool {
    env::args().any(|arg| arg == "service" || arg == "--service")
@@ -192,7 +194,7 @@
            trace_id,
        );
    }
    let child = match spawn_worker(&start_req, &profile, &state.config) {
    let child = match spawn_worker(&start_req, &profile, &state.config, trace_id.as_deref()) {
        Ok(value) => value,
        Err(spawn_error) => {
            warn!(
@@ -214,17 +216,27 @@
    let runtime_session_id = format!("rt_{}", start_req.call_id);
    let mut child = child;
    let child_stdout = child.stdout.take();
    let event_callback_url = start_req
        .event_callback
        .as_ref()
        .and_then(|value| value.url.clone())
        .filter(|value| !value.trim().is_empty());
    let event_callback_token = Some(profile.event_callback_token.clone());
    let event_callback_sender = if event_callback_url.is_some() {
        let (sender, receiver) = mpsc::channel();
        spawn_event_callback_worker(receiver);
        Some(sender)
    } else {
        None
    };
    let session = HelperSession {
        call_id: start_req.call_id.clone(),
        trace_id: trace_id.clone(),
        runtime_session_nonce: start_req.runtime_session_nonce.clone(),
        runtime_session_id,
        event_callback_url: start_req
            .event_callback
            .as_ref()
            .and_then(|value| value.url.clone())
            .filter(|value| !value.trim().is_empty()),
        event_callback_token: Some(profile.event_callback_token.clone()),
        event_callback_url,
        event_callback_token,
        event_callback_sender,
        status: "STARTING".to_string(),
        bot_participant_joined: false,
        bot_track_ready: false,
@@ -340,6 +352,7 @@
    req: &SessionStartRequest,
    profile: &AuthProfile,
    config: &ServiceConfig,
    trace_id: Option<&str>,
) -> Result<Child> {
    let exe = env::current_exe().context("failed to resolve helper executable")?;
    let mut command = Command::new(exe);
@@ -348,15 +361,15 @@
        .env("CV_CALL_ID", &req.call_id)
        .env(
            "CV_TRACE_ID",
            req.trace_id
                .clone()
            trace_id
                .map(str::to_string)
                .unwrap_or_else(|| format!("trace_{}", req.call_id)),
        )
        .env("CV_RUNTIME_CALL_ID", &req.call_id)
        .env(
            "CV_RUNTIME_TRACE_ID",
            req.trace_id
                .clone()
            trace_id
                .map(str::to_string)
                .unwrap_or_else(|| format!("trace_{}", req.call_id)),
        )
        .env("CV_RUNTIME_SESSION_NONCE", &req.runtime_session_nonce)
@@ -410,6 +423,18 @@
        if let Some(value) = &runtime.asr_stream_url {
            command.env("CV_RUNTIME_ASR_STREAM_URL", value);
        }
        if let Some(value) = runtime.asr_realtime_enabled {
            command.env("CV_RUNTIME_ASR_REALTIME_ENABLED", value.to_string());
        }
        if let Some(value) = &runtime.asr_realtime_url {
            command.env("CV_RUNTIME_ASR_REALTIME_URL", value);
        }
        if let Some(value) = runtime.asr_realtime_chunk_duration_ms {
            command.env(
                "CV_RUNTIME_ASR_REALTIME_CHUNK_DURATION_MS",
                value.to_string(),
            );
        }
        if let Some(true) = runtime.audio_debug_dump_enabled {
            if let Some(value) = &config.audio_debug_dump_dir {
                command.env("CV_AUDIO_DEBUG_DUMP_DIR", value);
@@ -451,11 +476,19 @@
                continue;
            };
            println!("{line}");
            if let Ok(value) = serde_json::from_str::<Value>(&line) {
            if let Some(value) = project_worker_stdout_event(&call_id, &line) {
                apply_worker_event(&call_id, &state, &value);
            }
        }
    });
}

fn project_worker_stdout_event(call_id: &str, line: &str) -> Option<Value> {
    let value = serde_json::from_str::<Value>(line).ok()?;
    (value.get("type").and_then(Value::as_str) == Some("cv_activity")
        && value.get("callId").and_then(Value::as_str) == Some(call_id)
        && value.get("eventName").and_then(Value::as_str).is_some())
    .then_some(value)
}

fn apply_worker_event(call_id: &str, state: &Arc<ServiceState>, value: &Value) {
@@ -470,16 +503,35 @@
        .and_then(Value::as_str)
        .unwrap_or("worker_event");
    let result = value.get("result").and_then(Value::as_str).unwrap_or("ok");
    let callback = {
    let queued_callback = {
        let Ok(mut sessions) = state.sessions.lock() else {
            return;
        };
        let Some(session) = sessions.get_mut(call_id) else {
            return;
        };
        let turn_id = value.get("turnId").and_then(Value::as_str);
        let terminal = matches!(
            event_name,
            "turn_completed" | "turn_failed" | "turn_cancelled"
        );
        if event_name == "turn_bridge_requested" {
            session.active_turn_id = turn_id.map(str::to_string);
        }
        session.last_event_type = Some(event_name.to_string());
        session.last_event_at = now_millis();
        let callback = build_event_callback_dispatch(session, value);
        let callback = if is_anchored_callback(value) && !anchored_callback_bound(session, value) {
            warn!(
                call_id = %call_id,
                trace_id = ?session.trace_id,
                event_name = %event_name,
                "helper rejected unbound anchored callback"
            );
            None
        } else {
            build_event_callback_dispatch(session, value)
        };
        let callback_sender = session.event_callback_sender.clone();
        if result != "ok" {
            session.status = "FAILED".to_string();
            session.bot_participant_joined = false;
@@ -500,10 +552,19 @@
                _ => {}
            }
        }
        callback
        if terminal && turn_id == session.active_turn_id.as_deref() {
            session.active_turn_id = None;
        }
        callback.zip(callback_sender)
    };
    if let Some(callback) = callback {
        dispatch_event_callback(callback);
    if let Some((callback, sender)) = queued_callback {
        if sender.send(callback).is_err() {
            warn!(
                call_id = %call_id,
                event_name = %event_name,
                "helper event callback queue closed"
            );
        }
    }
}

@@ -531,23 +592,55 @@
    })
}

fn dispatch_event_callback(callback: EventCallbackDispatch) {
fn spawn_event_callback_worker(receiver: mpsc::Receiver<EventCallbackDispatch>) {
    thread::spawn(move || {
        let event_name = callback
            .payload
            .get("eventName")
            .and_then(Value::as_str)
            .unwrap_or("worker_event")
            .to_string();
        match post_event_callback(&callback) {
        run_event_callback_worker(receiver, deliver_event_callback);
    });
}

fn run_event_callback_worker<F>(receiver: mpsc::Receiver<EventCallbackDispatch>, mut deliver: F)
where
    F: FnMut(EventCallbackDispatch),
{
    while let Ok(callback) = receiver.recv() {
        deliver(callback);
    }
}

fn deliver_event_callback(callback: EventCallbackDispatch) {
    deliver_event_callback_with(callback, post_event_callback);
}

fn deliver_event_callback_with<F>(callback: EventCallbackDispatch, mut post: F)
where
    F: FnMut(&EventCallbackDispatch) -> Result<u16>,
{
    let event_name = callback
        .payload
        .get("eventName")
        .and_then(Value::as_str)
        .unwrap_or("worker_event")
        .to_string();
    let max_attempts = if is_anchored_callback(&callback.payload) {
        ANCHORED_CALLBACK_MAX_ATTEMPTS
    } else {
        1
    };
    for attempt in 1..=max_attempts {
        let result = post(&callback);
        let retry =
            attempt < max_attempts && !matches!(&result, Ok(status) if (200..300).contains(status));
        match result {
            Ok(status) if (200..300).contains(&status) => {
                info!(
                    call_id = %callback.call_id,
                    trace_id = ?callback.trace_id,
                    event_name = %event_name,
                    status = status,
                    attempt = attempt,
                    "helper event callback delivered"
                );
                return;
            }
            Ok(status) => {
                warn!(
@@ -555,6 +648,7 @@
                    trace_id = ?callback.trace_id,
                    event_name = %event_name,
                    status = status,
                    attempt = attempt,
                    "helper event callback rejected"
                );
            }
@@ -563,12 +657,62 @@
                    call_id = %callback.call_id,
                    trace_id = ?callback.trace_id,
                    event_name = %event_name,
                    attempt = attempt,
                    error = %error,
                    "helper event callback failed"
                );
            }
        }
    });
        if retry {
            thread::sleep(ANCHORED_CALLBACK_RETRY_DELAY);
        }
    }
}

fn is_anchored_callback(payload: &Value) -> bool {
    matches!(
        payload.get("eventName").and_then(Value::as_str),
        Some("helper_first_reply_audio_chunk_received" | "bot_reply_first_audio_frame_written")
    ) && payload.get("serverDeltaSource").and_then(Value::as_str) == Some("stream_anchor_monotonic")
}

fn anchored_callback_bound(session: &HelperSession, payload: &Value) -> bool {
    let extension = payload.get("extension");
    let anchor_id = extension
        .and_then(|value| value.get("streamAnchorId"))
        .and_then(Value::as_str);
    let anchor_base = extension
        .and_then(|value| value.get("streamAnchorServerDeltaMs"))
        .and_then(Value::as_u64);
    let elapsed = extension
        .and_then(|value| value.get("anchorElapsedMs"))
        .and_then(Value::as_u64);
    let delta = payload.get("serverDeltaMs").and_then(Value::as_u64);
    let expected_delta =
        anchor_base.and_then(|base| elapsed.and_then(|value| base.checked_add(value)));
    let expected_nonce_hash = crate::runtime_session_nonce_hash(&session.runtime_session_nonce);
    payload.get("callId").and_then(Value::as_str) == Some(session.call_id.as_str())
        && payload.get("traceId").and_then(Value::as_str) == session.trace_id.as_deref()
        && payload.get("turnId").and_then(Value::as_str) == session.active_turn_id.as_deref()
        && extension
            .and_then(|value| value.get("streamTimingVersion"))
            .and_then(Value::as_u64)
            == Some(1)
        && anchor_id.is_some_and(|value| (16..=64).contains(&value.len()) && value.is_ascii())
        && extension
            .and_then(|value| value.get("runtimeSessionNonceHash"))
            .and_then(Value::as_str)
            == Some(expected_nonce_hash.as_str())
        && extension
            .and_then(|value| value.get("segmentSeq"))
            .and_then(Value::as_u64)
            == Some(1)
        && extension
            .and_then(|value| value.get("streamTimingValidation"))
            .and_then(Value::as_str)
            == Some("bound")
        && elapsed.is_some_and(|value| value <= 5_000)
        && delta == expected_delta
}

fn post_event_callback(callback: &EventCallbackDispatch) -> Result<u16> {
@@ -901,6 +1045,7 @@
    runtime_session_id: String,
    event_callback_url: Option<String>,
    event_callback_token: Option<String>,
    event_callback_sender: Option<mpsc::Sender<EventCallbackDispatch>>,
    status: String,
    bot_participant_joined: bool,
    bot_track_ready: bool,
@@ -976,6 +1121,9 @@
    audio_debug_dump_enabled: Option<bool>,
    asr_streaming_enabled: Option<bool>,
    asr_stream_url: Option<String>,
    asr_realtime_enabled: Option<bool>,
    asr_realtime_url: Option<String>,
    asr_realtime_chunk_duration_ms: Option<u64>,
}

#[derive(Default, Deserialize)]
@@ -1100,3 +1248,143 @@
        Err(_) => default_value,
    }
}

#[cfg(test)]
mod tests {
    use super::{
        EventCallbackDispatch, deliver_event_callback_with, project_worker_stdout_event,
        run_event_callback_worker,
    };
    use crate::{
        CONTROLLED_FIXTURE_GENERATION, CONTROLLED_FIXTURE_PROBE_TTL,
        ControlledFixtureVisibilityEvidence, PendingControlledFixtureProbe,
        controlled_fixture_probe_event, controlled_fixture_visibility_event,
    };
    use anyhow::Result;
    use serde_json::{Value, json};
    use std::{cell::RefCell, rc::Rc, sync::mpsc};

    #[test]
    fn controlled_fixture_activity_requires_production_stdout_envelope() {
        let call_id = "runtime-call";
        let runtime_trace_id = "runtime-trace";
        let trace_hash = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
        let valid = controlled_fixture_probe_event(
            call_id,
            runtime_trace_id,
            "ack_publish_completed",
            "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
            trace_hash,
            1,
            "fixture-01",
            false,
            Some("rejected"),
            Some("wrong_source"),
        );
        let projected = project_worker_stdout_event(call_id, &valid.to_string())
            .expect("valid activity must enter the production stdout projection");
        assert_eq!(projected["eventName"], "controlled_fixture_attribute_probe");
        assert_eq!(projected["extension"]["trace_id_hash"], trace_hash);
        assert_eq!(projected["extension"]["reject_reason"], "wrong_source");

        for invalid in [
            json!({
                "event": "controlled_fixture_attribute_probe",
                "stage": "ack_publish_completed",
                "observed": false,
                "ack_result": "rejected",
                "reject_reason": "wrong_source",
                "call_id_hash": "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
                "trace_id_hash": trace_hash,
                "generation": 1,
                "sequence_hash": "cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc"
            }),
            json!({"type": "not_activity", "callId": call_id, "eventName": "controlled_fixture_attribute_probe"}),
            json!({"type": "cv_activity", "callId": call_id}),
            json!({"type": "cv_activity", "callId": "wrong-call", "eventName": "controlled_fixture_attribute_probe"}),
        ] {
            assert!(project_worker_stdout_event(call_id, &invalid.to_string()).is_none());
        }

        let received_at = std::time::Instant::now();
        let visibility = controlled_fixture_visibility_event(
            call_id,
            runtime_trace_id,
            &PendingControlledFixtureProbe {
                sender: livekit::prelude::ParticipantIdentity("user-1".to_string()),
                call_id_hash: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
                    .to_string(),
                call_trace_id_hash: trace_hash.to_string(),
                generation: CONTROLLED_FIXTURE_GENERATION,
                sequence: "fixture-01".to_string(),
                received_at,
                expires_at: received_at + CONTROLLED_FIXTURE_PROBE_TTL,
            },
            &ControlledFixtureVisibilityEvidence {
                first_visible_bucket: "250_500ms",
                visibility_source: "participant_attributes_poll",
                visibility_result: "held_visible",
                binding_matched: true,
            },
        );
        let projected = project_worker_stdout_event(call_id, &visibility.to_string())
            .expect("post-expiry evidence must enter the production stdout projection");
        assert_eq!(projected["extension"]["first_visible_bucket"], "250_500ms");
        assert_eq!(projected["extension"]["binding_matched"], true);
        assert_eq!(projected["extension"]["visibility_result"], "held_visible");
    }

    #[test]
    fn same_session_callback_retries_m7_before_terminal() {
        let (sender, receiver) = mpsc::channel();
        let dispatch = |payload| EventCallbackDispatch {
            url: "http://callback.test/endpoint".to_string(),
            token: "test-token".to_string(),
            call_id: "call-1".to_string(),
            trace_id: Some("trace-1".to_string()),
            runtime_session_nonce: "test-nonce".to_string(),
            payload,
        };
        sender
            .send(dispatch(json!({
                "eventName": "bot_reply_first_audio_frame_written",
                "serverDeltaSource": "stream_anchor_monotonic"
            })))
            .expect("queue m7");
        sender
            .send(dispatch(json!({"eventName": "turn_completed"})))
            .expect("queue terminal");
        drop(sender);

        let observed = Rc::new(RefCell::new(Vec::new()));
        let observed_for_worker = observed.clone();
        run_event_callback_worker(receiver, move |callback| {
            let observed_for_post = observed_for_worker.clone();
            let mut m7_attempt = 0;
            deliver_event_callback_with(callback, move |dispatch| -> Result<u16> {
                let event_name = dispatch
                    .payload
                    .get("eventName")
                    .and_then(Value::as_str)
                    .expect("event name")
                    .to_string();
                observed_for_post.borrow_mut().push(event_name.clone());
                if event_name == "bot_reply_first_audio_frame_written" && m7_attempt == 0 {
                    m7_attempt += 1;
                    Ok(500)
                } else {
                    Ok(200)
                }
            });
        });

        assert_eq!(
            vec![
                "bot_reply_first_audio_frame_written",
                "bot_reply_first_audio_frame_written",
                "turn_completed"
            ],
            *observed.borrow()
        );
    }
}