Files
sglang/sgl-router/src/tool_parser/parsers/qwen_parser.rs

254 lines
8.8 KiB
Rust

use async_trait::async_trait;
use regex::Regex;
use serde_json::Value;
use crate::protocols::spec::Tool;
use crate::tool_parser::{
errors::{ToolParserError, ToolParserResult},
parsers::helpers,
partial_json::PartialJson,
traits::ToolParser,
types::{FunctionCall, StreamingParseResult, ToolCall},
};
/// Qwen format parser for tool calls
///
/// Handles the Qwen 2.5/3 specific format:
/// `<tool_call>\n{"name": "func", "arguments": {...}}\n</tool_call>`
///
/// Features:
/// - XML-style tags with JSON content
/// - Support for multiple sequential tool calls
/// - Newline-aware parsing
/// - Buffering for partial end tokens
pub struct QwenParser {
/// Parser for handling incomplete JSON during streaming
partial_json: PartialJson,
/// Regex for extracting tool calls in parse_complete
extractor: Regex,
/// Buffer for accumulating incomplete patterns across chunks
buffer: String,
/// Stores complete tool call info (name and arguments) for each tool being parsed
prev_tool_call_arr: Vec<Value>,
/// Index of currently streaming tool call (-1 means no active tool)
current_tool_id: i32,
/// Flag for whether current tool's name has been sent to client
current_tool_name_sent: bool,
/// Tracks raw JSON string content streamed to client for each tool's arguments
streamed_args_for_tool: Vec<String>,
/// Buffer for normal text that might precede partial end tokens
normal_text_buffer: String,
/// Token configuration
bot_token: &'static str,
eot_token: &'static str,
tool_call_separator: &'static str,
}
impl QwenParser {
/// Create a new Qwen parser
pub fn new() -> Self {
// Use (?s) flag for DOTALL mode to handle newlines
let pattern = r"(?s)<tool_call>\n(.*?)\n</tool_call>";
let extractor = Regex::new(pattern).expect("Valid regex pattern");
Self {
partial_json: PartialJson::default(),
extractor,
buffer: String::new(),
prev_tool_call_arr: Vec::new(),
current_tool_id: -1,
current_tool_name_sent: false,
streamed_args_for_tool: Vec::new(),
normal_text_buffer: String::new(),
bot_token: "<tool_call>\n",
eot_token: "\n</tool_call>",
tool_call_separator: "\n",
}
}
/// Parse a single JSON object into a ToolCall
fn parse_single_object(&self, obj: &Value) -> ToolParserResult<Option<ToolCall>> {
let name = obj.get("name").and_then(|v| v.as_str());
if let Some(name) = name {
// Get arguments - Qwen uses "arguments" key
let empty_obj = Value::Object(serde_json::Map::new());
let args = obj.get("arguments").unwrap_or(&empty_obj);
// Convert arguments to JSON string
let arguments = serde_json::to_string(args)
.map_err(|e| ToolParserError::ParsingFailed(e.to_string()))?;
Ok(Some(ToolCall {
function: FunctionCall {
name: name.to_string(),
arguments,
},
}))
} else {
Ok(None)
}
}
/// Check if text contains Qwen tool markers
fn has_tool_markers(&self, text: &str) -> bool {
text.contains("<tool_call>")
}
/// Check if text has tool call
fn has_tool_call(&self, text: &str) -> bool {
text.contains("<tool_call>")
}
}
impl Default for QwenParser {
fn default() -> Self {
Self::new()
}
}
#[async_trait]
impl ToolParser for QwenParser {
async fn parse_complete(&self, text: &str) -> ToolParserResult<(String, Vec<ToolCall>)> {
// Check if text contains Qwen format
if !self.has_tool_markers(text) {
return Ok((text.to_string(), vec![]));
}
// Find where the first tool call begins
let idx = text.find("<tool_call>").unwrap(); // Safe because has_tool_markers checked
let normal_text = text[..idx].to_string();
// Extract tool calls
let mut tools = Vec::new();
for captures in self.extractor.captures_iter(text) {
if let Some(json_str) = captures.get(1) {
let parsed = serde_json::from_str::<Value>(json_str.as_str().trim())
.map_err(|e| ToolParserError::ParsingFailed(e.to_string()))
.and_then(|v| self.parse_single_object(&v));
match parsed {
Ok(Some(tool)) => tools.push(tool),
Ok(None) => continue,
Err(e) => {
tracing::warn!("Failed to parse tool call: {:?}", e);
continue;
}
}
}
}
// If no tools were successfully parsed despite having markers, return entire text as fallback
if tools.is_empty() {
return Ok((text.to_string(), vec![]));
}
Ok((normal_text, tools))
}
async fn parse_incremental(
&mut self,
chunk: &str,
tools: &[Tool],
) -> ToolParserResult<StreamingParseResult> {
// Append new text to buffer
self.buffer.push_str(chunk);
let current_text = &self.buffer.clone();
// Check if current_text has tool_call
let has_tool_start = self.has_tool_call(current_text)
|| (self.current_tool_id >= 0 && current_text.starts_with(self.tool_call_separator));
if !has_tool_start {
// Only clear buffer if we're sure no tool call is starting
if helpers::ends_with_partial_token(&self.buffer, self.bot_token).is_none() {
let normal_text = self.buffer.clone();
self.buffer.clear();
return Ok(StreamingParseResult {
normal_text,
calls: vec![],
});
} else {
// Might be partial bot_token, keep buffering
return Ok(StreamingParseResult::default());
}
}
// Build tool indices
let tool_indices = helpers::get_tool_indices(tools);
// Determine start index for JSON parsing
let start_idx = if let Some(pos) = current_text.find(self.bot_token) {
pos + self.bot_token.len()
} else if self.current_tool_id >= 0 && current_text.starts_with(self.tool_call_separator) {
self.tool_call_separator.len()
} else {
0
};
let mut result = helpers::handle_json_tool_streaming(
current_text,
start_idx,
&mut self.partial_json,
&tool_indices,
&mut self.buffer,
&mut self.current_tool_id,
&mut self.current_tool_name_sent,
&mut self.streamed_args_for_tool,
&mut self.prev_tool_call_arr,
)?;
// Qwen-specific: Handle partial end tokens in normal text
// After tool calls complete, normal text might contain partial "</tool_call>" tags
if !result.normal_text.is_empty() {
self.normal_text_buffer.push_str(&result.normal_text);
// Check if buffer contains complete end token (without leading newline)
let end_token_without_newline = &self.eot_token[1..]; // "</tool_call>"
if self.normal_text_buffer.contains(end_token_without_newline) {
// Complete end token found - clean it and return
let cleaned_text = self
.normal_text_buffer
.replace(end_token_without_newline, "");
self.normal_text_buffer.clear();
result.normal_text = cleaned_text;
} else {
// Check if buffer might contain partial end token at the end
if let Some(partial_match_len) = helpers::ends_with_partial_token(
&self.normal_text_buffer,
end_token_without_newline,
) {
// Keep potential partial match in buffer, return the rest
let split_point = self.normal_text_buffer.len() - partial_match_len;
result.normal_text = self.normal_text_buffer[..split_point].to_string();
self.normal_text_buffer = self.normal_text_buffer[split_point..].to_string();
} else {
// No partial match, return all buffered text
result.normal_text = self.normal_text_buffer.clone();
self.normal_text_buffer.clear();
}
}
}
Ok(result)
}
fn detect_format(&self, text: &str) -> bool {
self.has_tool_markers(text)
}
fn get_unstreamed_tool_args(&self) -> Option<Vec<crate::tool_parser::types::ToolCallItem>> {
helpers::get_unstreamed_args(&self.prev_tool_call_arr, &self.streamed_args_for_tool)
}
}