refactor(chat): unify generation flow and fix tool/streaming bugs

- Unified synchronous generate() core with callback; both streaming and
  non-streaming paths run it via spawn_blocking (context: std Mutex).
- build_prompt now passes tool definitions to the template (was dead) and
  embeds assistant tool-call history as XML matching the parser format;
  fixes double <tool_response> wrap and template set-scoping bug.
- Tokenize with AddBos::Never (template owns <s>) to remove double BOS.
- Streaming: preserve inter-word spaces (per-chunk trim removed), add
  [DONE] + usage chunk, emit error events, single-shot tool_calls delta.
- Strict model validation (400 on unknown model); health/UI/README aligned
  to minicpm5-1b-fable5-v2-thinking; auth returns JSON errors; n_ctx/
  n_batch/n_threads env-configurable.
- Added 18 unit tests; cargo check/clippy/fmt clean.
- scripts/smoke-test.sh for post-deploy verification on the VPS.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
asepharyana
2026-08-03 08:58:13 +07:00
co-authored by Claude Opus 5
parent 344bc195fa
commit b636496497
14 changed files with 883 additions and 445 deletions
+75 -62
View File
@@ -4,6 +4,7 @@
//! lifetime transmute), tokenization, and generation.
use std::num::NonZeroU32;
use std::sync::Mutex;
use llama_cpp_2::context::params::LlamaContextParams;
use llama_cpp_2::context::LlamaContext;
@@ -14,10 +15,10 @@ use llama_cpp_2::model::{AddBos, LlamaModel};
use llama_cpp_2::sampling::LlamaSampler;
use llama_cpp_2::token::LlamaToken;
use llama_cpp_2::TokenToStringError;
use tokio::sync::Mutex;
use tracing::info;
use crate::config::CONFIG;
use crate::domain::entity::FinishReason;
use crate::domain::LlmError;
// ── Thread-safe wrapper for raw llama.cpp context ──
@@ -95,17 +96,28 @@ impl CtxInner {
// ── LlamaEngine ──
/// Outcome of a generation run.
pub struct GenerationOutcome {
/// Generated tokens (stop-sequence and EOG tokens are excluded).
pub tokens: Vec<LlamaToken>,
/// Accumulated decoded text (raw, before markup/special-token cleaning).
pub text: String,
/// Why generation stopped.
pub finish: FinishReason,
}
/// Safe interface to a llama.cpp model and inference context.
///
/// All access to the underlying context is serialized through a `Mutex`,
/// so only one generation can happen at a time. This is intentional —
/// the model is designed for sequential inference.
/// the model is designed for sequential inference. Generation is synchronous
/// and must be invoked from the tokio blocking pool (`spawn_blocking`).
pub struct LlamaEngine {
/// The loaded model (read-only after load, safe to share).
pub model: LlamaModel,
/// The inference context (single-threaded access via Mutex).
pub ctx: Mutex<CtxInner>,
ctx: Mutex<CtxInner>,
}
impl LlamaEngine {
@@ -117,17 +129,17 @@ impl LlamaEngine {
/// cannot be created.
pub fn load() -> Result<Self, LlmError> {
info!("Initializing llama backend...");
let backend = LlamaBackend::init().map_err(|e| {
LlmError::Model(format!("Backend init failed: {e}"))
})?;
let backend = LlamaBackend::init()
.map_err(|e| LlmError::Model(format!("Backend init failed: {e}")))?;
// Backend must outlive model and context. We leak it to achieve 'static
// lifetime since the engine lives for the program lifetime.
let backend: &'static LlamaBackend = Box::leak(Box::new(backend));
info!("Loading model: {}", CONFIG.model_path);
let model = LlamaModel::load_from_file(backend, &CONFIG.model_path, &LlamaModelParams::default())
.map_err(|e| LlmError::Model(format!("Failed to load model: {e}")))?;
let model =
LlamaModel::load_from_file(backend, &CONFIG.model_path, &LlamaModelParams::default())
.map_err(|e| LlmError::Model(format!("Failed to load model: {e}")))?;
info!(" Vocab: {}", model.n_vocab());
info!(" Params: {}", model.n_params());
info!(" Layers: {}", model.n_layer());
@@ -156,9 +168,12 @@ impl LlamaEngine {
}
/// Tokenize a prompt string into tokens.
///
/// `AddBos::Never`: the chat template already prepends the `<s>` BOS token,
/// so adding another here would produce a double BOS.
pub fn tokenize(&self, prompt: &str) -> Result<Vec<LlamaToken>, LlmError> {
self.model
.str_to_token(prompt, AddBos::Always)
.str_to_token(prompt, AddBos::Never)
.map_err(|e| LlmError::Model(format!("Tokenization failed: {e}")))
}
@@ -177,37 +192,28 @@ impl LlamaEngine {
String::from_utf8(bytes).unwrap_or_default()
}
/// Decode multiple tokens to a single string.
pub fn decode_tokens(&self, tokens: &[LlamaToken]) -> String {
let mut out = String::with_capacity(tokens.len() * 4);
for &token in tokens {
out.push_str(&self.decode_token(token));
}
out
}
/// Check if a token is an end-of-generation token.
pub fn is_eog(&self, token: LlamaToken) -> bool {
self.model.is_eog_token(token)
}
/// Return a reference to the context mutex for advanced operations.
pub fn ctx(&self) -> &Mutex<CtxInner> {
&self.ctx
}
/// Generate tokens (non-streaming) and return output tokens, cleaned text, and tool calls.
/// Generate tokens and invoke `on_token` for each one.
///
/// Locks the context mutex, prefill the prompt, then iterates sampling + decoding
/// until EOG, max_tokens, stop sequence, or tool call completion.
pub async fn generate(
/// Synchronous (CPU-bound) — call from `spawn_blocking`. Locks the context,
/// prefills the prompt, then iterates sampling + decoding until EOG,
/// `max_tokens`, a stop sequence, or a complete `<tool_call>` block.
///
/// `on_token` is invoked for every generated token (after leading-EOG
/// skipping, before it is decoded into the KV cache) and may return `false`
/// to abort early (e.g. the streaming client disconnected).
pub fn generate(
&self,
input_tokens: &[LlamaToken],
sampler: &mut SendSampler,
sampler: &mut LlamaSampler,
max_tokens: u32,
stop: &[String],
) -> Result<(Vec<LlamaToken>, String), LlmError> {
let mut inner = self.ctx.lock().await;
enable_tool_detection: bool,
on_token: &mut dyn FnMut(LlamaToken, &str) -> bool,
) -> Result<GenerationOutcome, LlmError> {
let mut inner = self
.ctx
.lock()
.map_err(|_| LlmError::Internal("context mutex poisoned".into()))?;
inner.clear();
inner
.prefill(input_tokens)
@@ -215,59 +221,66 @@ impl LlamaEngine {
let mut output: Vec<LlamaToken> = Vec::new();
let mut text_buf = String::new();
let mut stop_now = false;
let mut finish = FinishReason::Length;
let mut current = inner.sample(sampler);
// Skip leading EOS tokens (like <|im_end|> as first token)
// Skip leading EOG tokens (like a stray <|im_end|> right after the prompt)
while output.is_empty() && self.model.is_eog_token(current) {
let pos = input_tokens.len() as i32 + output.len() as i32;
if let Err(e) = inner.decode(current, pos) {
tracing::info!(" Decode error: {e}");
break;
}
inner
.decode(current, pos)
.map_err(|e| LlmError::Model(format!("Decode: {e}")))?;
current = inner.sample(sampler);
}
for _ in 0..max_tokens {
if self.model.is_eog_token(current) {
finish = FinishReason::Stop;
break;
}
let piece = self.decode_token(current);
// Check stop sequences *before* committing, so the stop tokens never
// leak into the output text or the stream.
if stop
.iter()
.any(|s| !s.is_empty() && format!("{text_buf}{piece}").contains(s))
{
finish = FinishReason::Stop;
break;
}
let pos = input_tokens.len() as i32 + output.len() as i32;
output.push(current);
let piece = self.decode_token(current);
text_buf.push_str(&piece);
// Check stop sequences
for s in stop {
if text_buf.contains(s) {
stop_now = true;
break;
}
}
if stop_now {
break;
}
// Check for tool_call block completion
if text_buf.contains("<tool_call>") {
let close_count = text_buf.matches("</tool_call>").count();
let open_count = text_buf.matches("<tool_call>").count();
if open_count > 0 && close_count >= open_count {
// Complete <tool_call> block emitted?
if enable_tool_detection && text_buf.contains("<tool_call>") {
let open = text_buf.matches("<tool_call>").count();
let close = text_buf.matches("</tool_call>").count();
if close >= open {
finish = FinishReason::ToolCalls;
break;
}
}
if let Err(e) = inner.decode(current, pos) {
tracing::info!(" Decode error: {e}");
if !on_token(current, &piece) {
finish = FinishReason::Aborted;
break;
}
inner
.decode(current, pos)
.map_err(|e| LlmError::Model(format!("Decode: {e}")))?;
current = inner.sample(sampler);
}
Ok((output, text_buf))
Ok(GenerationOutcome {
tokens: output,
text: text_buf,
finish,
})
}
}