[router] global tool parser registry (#9840)

sgl-router/Cargo.toml

@@ -64,6 +64,7 @@ prost-types = "0.13"
 deadpool = { version = "0.12", features = ["managed", "rt_tokio_1"] }
 backoff = { version = "0.4", features = ["tokio"] }
 strum = { version = "0.26", features = ["derive"] }
+once_cell = "1.21.3"
 
 [build-dependencies]
 tonic-build = "0.12"

sgl-router/src/tool_parser/parsers/pythonic_parser.rs

@@ -23,6 +23,8 @@ use crate::tool_parser::{
 pub struct PythonicParser {
     /// Regex to detect tool calls in Pythonic format
     tool_call_regex: Regex,
+    /// Regex to parse function calls - cached for reuse
+    call_regex: Regex,
 }
 
 impl PythonicParser {
@@ -33,7 +35,13 @@ impl PythonicParser {
         let pattern = r"\[[a-zA-Z_]\w*\(";
         let tool_call_regex = Regex::new(pattern).expect("Valid regex pattern");
 
-        Self { tool_call_regex }
+        // Compile the function call regex once
+        let call_regex = Regex::new(r"(?s)^([a-zA-Z_]\w*)\((.*)\)$").expect("Valid regex pattern");
+
+        Self {
+            tool_call_regex,
+            call_regex,
+        }
     }
 
     /// Extract tool calls using bracket counting (similar to MistralParser)
@@ -120,10 +128,8 @@ impl PythonicParser {
 
     /// Parse a single function call from Python syntax
     fn parse_function_call(&self, call_str: &str) -> ToolParserResult<Option<ToolCall>> {
-        // Match function_name(args) - use (?s) to make . match newlines
-        let call_regex = Regex::new(r"(?s)^([a-zA-Z_]\w*)\((.*)\)$").unwrap();
-
-        if let Some(captures) = call_regex.captures(call_str.trim()) {
+        // Use cached regex instead of creating new one
+        if let Some(captures) = self.call_regex.captures(call_str.trim()) {
             let function_name = captures.get(1).unwrap().as_str();
             let args_str = captures.get(2).unwrap().as_str();
 

sgl-router/src/tool_parser/registry.rs

@@ -3,9 +3,13 @@ use crate::tool_parser::parsers::{
     MistralParser, PythonicParser, QwenParser, Step3Parser,
 };
 use crate::tool_parser::traits::ToolParser;
+use once_cell::sync::Lazy;
 use std::collections::HashMap;
 use std::sync::Arc;
 
+/// Global singleton registry instance - created once and reused
+pub static GLOBAL_REGISTRY: Lazy<ParserRegistry> = Lazy::new(ParserRegistry::new_internal);
+
 /// Registry for tool parsers and model mappings
 pub struct ParserRegistry {
     /// Map of parser name to parser instance
@@ -17,8 +21,19 @@ pub struct ParserRegistry {
 }
 
 impl ParserRegistry {
-    /// Create a new parser registry with default mappings
-    pub fn new() -> Self {
+    /// Get the global singleton instance
+    pub fn new() -> &'static Self {
+        &GLOBAL_REGISTRY
+    }
+
+    /// Create a new instance for testing (not the singleton)
+    #[cfg(test)]
+    pub fn new_for_testing() -> Self {
+        Self::new_internal()
+    }
+
+    /// Internal constructor for creating the singleton instance
+    fn new_internal() -> Self {
         let mut registry = Self {
             parsers: HashMap::new(),
             model_mapping: HashMap::new(),
@@ -202,8 +217,8 @@ impl ParserRegistry {
     }
 }
 
-impl Default for ParserRegistry {
+impl Default for &'static ParserRegistry {
     fn default() -> Self {
-        Self::new()
+        ParserRegistry::new()
     }
 }

sgl-router/src/tool_parser/tests.rs

@@ -74,7 +74,7 @@ fn test_parser_registry() {
 
 #[test]
 fn test_parser_registry_pattern_matching() {
-    let mut registry = ParserRegistry::new();
+    let mut registry = ParserRegistry::new_for_testing();
 
     // Test that model mappings work by checking the list
     registry.map_model("test-model", "json");