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Diffstat (limited to 'makima/src/server/handlers/speak.rs')
| -rw-r--r-- | makima/src/server/handlers/speak.rs | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/makima/src/server/handlers/speak.rs b/makima/src/server/handlers/speak.rs new file mode 100644 index 0000000..75e7780 --- /dev/null +++ b/makima/src/server/handlers/speak.rs @@ -0,0 +1,274 @@ +//! WebSocket handler for TTS streaming (direct in-process inference). +//! +//! This module implements the `/api/v1/speak` endpoint which performs +//! text-to-speech synthesis directly using the candle-based TTS engine. +//! No external Python service or proxy — the model runs in-process. +//! +//! ## Architecture +//! +//! The speak handler will: +//! 1. Accept a WebSocket connection from the client +//! 2. Lazily load the TTS model (candle) on first request +//! 3. Parse JSON control messages (start, speak, stop, cancel) +//! 4. Run inference directly and stream audio chunks back +//! +//! See `makima/src/tts/` for the TTS engine implementation. +//! See `docs/specs/qwen3-tts-spec.md` for the full protocol specification. + +use axum::{ + extract::{ws::Message, ws::WebSocket, State, WebSocketUpgrade}, + response::Response, +}; +use futures::{SinkExt, StreamExt}; +use serde::Deserialize; +use uuid::Uuid; + +use crate::server::state::SharedState; + +/// Client-to-server control messages. +#[derive(Debug, Deserialize)] +#[serde(tag = "type", rename_all = "snake_case")] +enum ClientMessage { + /// Request speech synthesis for the given text. + Speak { + text: String, + /// Optional voice ID (e.g., "makima"). Not yet used — reserved for future voice selection. + #[serde(default)] + #[allow(dead_code)] + voice: Option<String>, + }, + /// Cancel any in-progress synthesis. + Cancel, + /// Graceful close. + Stop, +} + +/// WebSocket upgrade handler for TTS streaming. +/// +/// This endpoint accepts WebSocket connections for text-to-speech synthesis. +/// The TTS model runs directly in-process using candle — no external service. +#[utoipa::path( + get, + path = "/api/v1/speak", + responses( + (status = 101, description = "WebSocket connection established"), + (status = 503, description = "TTS engine not available"), + ), + tag = "Speak" +)] +pub async fn websocket_handler( + ws: WebSocketUpgrade, + State(state): State<SharedState>, +) -> Response { + ws.on_upgrade(|socket| handle_speak_socket(socket, state)) +} + +/// Handle TTS WebSocket session with direct in-process inference. +/// +/// Protocol: +/// - Client sends JSON `{ "type": "speak", "text": "..." }` messages +/// - Server responds with binary audio chunks (16-bit PCM @ 24kHz) +/// - Server sends JSON `{ "type": "audio_end" }` when synthesis is complete +/// - Server sends JSON `{ "type": "error", ... }` on failures +async fn handle_speak_socket(socket: WebSocket, state: SharedState) { + let session_id = Uuid::new_v4().to_string(); + tracing::info!(session_id = %session_id, "New TTS WebSocket connection"); + + let (mut sender, mut receiver) = socket.split(); + + // Process incoming messages + while let Some(msg) = receiver.next().await { + let msg = match msg { + Ok(m) => m, + Err(e) => { + tracing::warn!(session_id = %session_id, error = %e, "WebSocket receive error"); + break; + } + }; + + match msg { + Message::Text(text) => { + let client_msg: ClientMessage = match serde_json::from_str(&text) { + Ok(m) => m, + Err(e) => { + let _ = send_error( + &mut sender, + "INVALID_MESSAGE", + &format!("Failed to parse message: {e}"), + ) + .await; + continue; + } + }; + + match client_msg { + ClientMessage::Speak { text, .. } => { + tracing::info!( + session_id = %session_id, + text_len = text.len(), + "TTS speak request" + ); + + // Get or lazily load the TTS engine + let engine = match state.get_tts_engine().await { + Ok(e) => e, + Err(e) => { + tracing::error!( + session_id = %session_id, + error = %e, + "Failed to load TTS engine" + ); + let _ = send_error( + &mut sender, + "TTS_LOAD_FAILED", + &format!("Failed to load TTS engine: {e}"), + ) + .await; + continue; + } + }; + + if !engine.is_ready() { + let _ = send_error( + &mut sender, + "TTS_NOT_READY", + "TTS engine is not ready yet", + ) + .await; + continue; + } + + // Run TTS inference (no voice reference for now — uses default) + match engine.generate(&text, None, None).await { + Ok(chunks) => { + for chunk in &chunks { + // Send binary PCM audio data + let pcm_bytes = chunk.to_pcm16_bytes(); + if sender + .send(Message::Binary(pcm_bytes.into())) + .await + .is_err() + { + tracing::warn!( + session_id = %session_id, + "Failed to send audio chunk — client disconnected" + ); + return; + } + } + + // Signal end of audio + let end_msg = serde_json::json!({ + "type": "audio_end", + "sample_rate": engine.sample_rate(), + "format": "pcm_s16le", + "channels": 1, + }); + let _ = sender + .send(Message::Text(end_msg.to_string().into())) + .await; + } + Err(e) => { + tracing::error!( + session_id = %session_id, + error = %e, + "TTS inference failed" + ); + let _ = send_error( + &mut sender, + "TTS_INFERENCE_FAILED", + &format!("TTS inference failed: {e}"), + ) + .await; + } + } + } + ClientMessage::Cancel => { + tracing::info!(session_id = %session_id, "TTS cancel requested"); + // TODO: support cancellation of in-progress inference + } + ClientMessage::Stop => { + tracing::info!(session_id = %session_id, "TTS stop requested, closing"); + break; + } + } + } + Message::Close(_) => { + tracing::info!(session_id = %session_id, "TTS WebSocket closed by client"); + break; + } + _ => { + // Ignore ping/pong/binary from client + } + } + } + + tracing::info!(session_id = %session_id, "TTS WebSocket connection closed"); +} + +/// Send an error message to the client. +async fn send_error<S>(sender: &mut S, code: &str, message: &str) -> Result<(), axum::Error> +where + S: SinkExt<Message> + Unpin, + <S as futures::Sink<Message>>::Error: std::error::Error, +{ + let error_msg = serde_json::json!({ + "type": "error", + "code": code, + "message": message, + "recoverable": false + }); + + sender + .send(Message::Text(error_msg.to_string().into())) + .await + .ok(); + Ok(()) +} + +#[cfg(test)] +mod tests { + use super::*; + + #[test] + fn test_error_message_format() { + let error = serde_json::json!({ + "type": "error", + "code": "TEST_ERROR", + "message": "Test message", + "recoverable": false + }); + + assert_eq!(error["type"], "error"); + assert_eq!(error["code"], "TEST_ERROR"); + assert_eq!(error["message"], "Test message"); + assert_eq!(error["recoverable"], false); + } + + #[test] + fn test_client_message_parse_speak() { + let json = r#"{"type": "speak", "text": "Hello world"}"#; + let msg: ClientMessage = serde_json::from_str(json).unwrap(); + match msg { + ClientMessage::Speak { text, voice } => { + assert_eq!(text, "Hello world"); + assert!(voice.is_none()); + } + _ => panic!("Expected Speak message"), + } + } + + #[test] + fn test_client_message_parse_cancel() { + let json = r#"{"type": "cancel"}"#; + let msg: ClientMessage = serde_json::from_str(json).unwrap(); + assert!(matches!(msg, ClientMessage::Cancel)); + } + + #[test] + fn test_client_message_parse_stop() { + let json = r#"{"type": "stop"}"#; + let msg: ClientMessage = serde_json::from_str(json).unwrap(); + assert!(matches!(msg, ClientMessage::Stop)); + } +} |
