Add controlled fixture ACK observability

cai

2026-08-12 9eca12eae4372c79eb35cef972f1ab4756c0a5e0

 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!(
@@ -214,11 +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,
        event_callback_token,
        event_callback_sender,
        status: "STARTING".to_string(),
        bot_participant_joined: false,
        bot_track_ready: false,
@@ -334,6 +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);
@@ -342,15 +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)
@@ -373,6 +392,48 @@
    if let Some(runtime) = &req.runtime {
        if let Some(value) = &runtime.turn_artifact_dir {
            command.env("CV_RUNTIME_TURN_ARTIFACT_DIR", value);
        }
        if let Some(value) = runtime.vad_rms_threshold {
            command.env("CV_VAD_RMS_THRESHOLD", value.to_string());
        }
        if let Some(value) = runtime.vad_peak_threshold {
            command.env("CV_VAD_PEAK_THRESHOLD", value.to_string());
        }
        if let Some(value) = runtime.vad_start_frames {
            command.env("CV_VAD_START_FRAMES", value.to_string());
        }
        if let Some(value) = runtime.vad_end_silence_ms {
            command.env("CV_VAD_END_SILENCE_MS", value.to_string());
        }
        if let Some(value) = runtime.vad_min_speech_ms {
            command.env("CV_VAD_MIN_SPEECH_MS", value.to_string());
        }
        if let Some(value) = runtime.vad_max_turn_ms {
            command.env("CV_VAD_MAX_TURN_MS", value.to_string());
        }
        if let Some(value) = runtime.vad_initial_ignore_ms {
            command.env("CV_VAD_INITIAL_IGNORE_MS", value.to_string());
        }
        if let Some(value) = runtime.vad_post_greeting_delay_ms {
            command.env("CV_VAD_POST_GREETING_DELAY_MS", value.to_string());
        }
        if let Some(value) = runtime.asr_streaming_enabled {
            command.env("CV_RUNTIME_ASR_STREAM_ENABLED", value.to_string());
        }
        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 {
@@ -434,34 +495,270 @@
        .and_then(Value::as_str)
        .unwrap_or("worker_event");
    let result = value.get("result").and_then(Value::as_str).unwrap_or("ok");
    let Ok(mut sessions) = state.sessions.lock() else {
        return;
    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 = 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;
            session.bot_track_ready = false;
        } else {
            match event_name {
                "helper_worker_started" => {
                    session.status = "STARTING".to_string();
                }
                "bot_participant_joined" => {
                    session.bot_participant_joined = true;
                }
                "bot_track_ready" => {
                    session.bot_participant_joined = true;
                    session.bot_track_ready = true;
                    session.status = "STARTED".to_string();
                }
                _ => {}
            }
        }
        if terminal && turn_id == session.active_turn_id.as_deref() {
            session.active_turn_id = None;
        }
        callback.zip(callback_sender)
    };
    let Some(session) = sessions.get_mut(call_id) else {
        return;
    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"
            );
        }
    }
}

fn build_event_callback_dispatch(
    session: &HelperSession,
    value: &Value,
) -> Option<EventCallbackDispatch> {
    let url = session
        .event_callback_url
        .as_ref()
        .filter(|value| !value.trim().is_empty())?
        .clone();
    let token = session
        .event_callback_token
        .as_ref()
        .filter(|value| !value.trim().is_empty())?
        .clone();
    Some(EventCallbackDispatch {
        url,
        token,
        call_id: session.call_id.clone(),
        trace_id: session.trace_id.clone(),
        runtime_session_nonce: session.runtime_session_nonce.clone(),
        payload: value.clone(),
    })
}

fn spawn_event_callback_worker(receiver: mpsc::Receiver<EventCallbackDispatch>) {
    thread::spawn(move || {
        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
    };
    session.last_event_type = Some(event_name.to_string());
    session.last_event_at = now_millis();
    if result != "ok" {
        session.status = "FAILED".to_string();
        session.bot_participant_joined = false;
        session.bot_track_ready = false;
        return;
    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!(
                    call_id = %callback.call_id,
                    trace_id = ?callback.trace_id,
                    event_name = %event_name,
                    status = status,
                    attempt = attempt,
                    "helper event callback rejected"
                );
            }
            Err(error) => {
                warn!(
                    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);
        }
    }
    match event_name {
        "helper_worker_started" => {
            session.status = "STARTING".to_string();
        }
        "bot_participant_joined" => {
            session.bot_participant_joined = true;
        }
        "bot_track_ready" => {
            session.bot_participant_joined = true;
            session.bot_track_ready = true;
            session.status = "STARTED".to_string();
        }
        _ => {}
}

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> {
    let (host, path) = parse_http_url(&callback.url)?;
    let body = serde_json::to_vec(&callback.payload)?;
    let mut stream = TcpStream::connect(&host)
        .with_context(|| format!("failed to connect callback host {host}"))?;
    stream.set_read_timeout(Some(Duration::from_secs(3)))?;
    stream.set_write_timeout(Some(Duration::from_secs(3)))?;
    let trace_header = callback.trace_id.clone().unwrap_or_default();
    let request = format!(
        "POST {path} HTTP/1.1\r\n\
         Host: {host}\r\n\
         Authorization: Bearer {}\r\n\
         X-CV-Runtime-Token: {}\r\n\
         X-CV-Call-Id: {}\r\n\
         X-CV-Trace-Id: {}\r\n\
         X-CV-Runtime-Session-Nonce: {}\r\n\
         Content-Type: application/json\r\n\
         Content-Length: {}\r\n\
         Connection: close\r\n\
         \r\n",
        callback.token,
        callback.token,
        callback.call_id,
        trace_header,
        callback.runtime_session_nonce,
        body.len()
    );
    stream.write_all(request.as_bytes())?;
    stream.write_all(&body)?;
    stream.flush()?;
    let mut response = String::new();
    stream.read_to_string(&mut response)?;
    response
        .lines()
        .next()
        .and_then(|line| line.split_whitespace().nth(1))
        .and_then(|value| value.parse::<u16>().ok())
        .ok_or_else(|| anyhow!("callback response status missing"))
}

fn parse_http_url(url: &str) -> Result<(String, String)> {
    let Some(rest) = url.strip_prefix("http://") else {
        return Err(anyhow!("only http callback url is supported"));
    };
    let (host, path) = match rest.split_once('/') {
        Some((host, path)) => (host, format!("/{path}")),
        None => (rest, "/".to_string()),
    };
    if host.trim().is_empty() {
        return Err(anyhow!("callback host missing"));
    }
    Ok((host.to_string(), path))
}

enum WaitReadyResult {
@@ -692,6 +989,7 @@
struct AuthProfile {
    helper_auth_token: String,
    turn_bridge_token: String,
    event_callback_token: String,
}

impl AuthProfile {
@@ -707,11 +1005,24 @@
        let turn_bridge_token = env::var(format!("CV_TURN_BRIDGE_TOKEN_{suffix}"))
            .or_else(|_| env::var("CV_RUNTIME_TURN_BRIDGE_TOKEN"))
            .ok()?;
        let event_callback_token = env::var(format!("CV_EVENT_CALLBACK_TOKEN_{suffix}"))
            .or_else(|_| env::var("CV_RUNTIME_EVENT_CALLBACK_TOKEN"))
            .unwrap_or_else(|_| turn_bridge_token.clone());
        Some(Self {
            helper_auth_token,
            turn_bridge_token,
            event_callback_token,
        })
    }
}

struct EventCallbackDispatch {
    url: String,
    token: String,
    call_id: String,
    trace_id: Option<String>,
    runtime_session_nonce: String,
    payload: Value,
}

struct ServiceState {
@@ -724,6 +1035,9 @@
    trace_id: Option<String>,
    runtime_session_nonce: String,
    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,
@@ -742,6 +1056,7 @@
    runtime_session_nonce: String,
    livekit: LiveKitStart,
    turn_bridge: Option<TurnBridgeStart>,
    event_callback: Option<EventCallbackStart>,
    auth_profile: Option<String>,
    audio: Option<AudioStart>,
    runtime: Option<RuntimeStart>,
@@ -765,6 +1080,12 @@

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct EventCallbackStart {
    url: Option<String>,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct AudioStart {
    first_audio_source: Option<String>,
    greeting_audio: Option<GreetingAudioStart>,
@@ -781,7 +1102,20 @@
#[serde(rename_all = "camelCase")]
struct RuntimeStart {
    turn_artifact_dir: Option<String>,
    vad_rms_threshold: Option<f64>,
    vad_peak_threshold: Option<f64>,
    vad_start_frames: Option<u32>,
    vad_end_silence_ms: Option<u64>,
    vad_min_speech_ms: Option<u64>,
    vad_max_turn_ms: Option<u64>,
    vad_initial_ignore_ms: Option<u64>,
    vad_post_greeting_delay_ms: Option<u64>,
    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)]
@@ -906,3 +1240,65 @@
        Err(_) => default_value,
    }
}

#[cfg(test)]
mod tests {
    use super::{EventCallbackDispatch, deliver_event_callback_with, run_event_callback_worker};
    use anyhow::Result;
    use serde_json::{Value, json};
    use std::{cell::RefCell, rc::Rc, sync::mpsc};

    #[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()
        );
    }
}