init

vw-agentic-rag/service/utils/templates.py

@@ -0,0 +1,103 @@
+"""
+Template utilities for Jinja2 template rendering with LangChain
+"""
+import logging
+from typing import Dict, Any
+from jinja2 import Environment, BaseLoader, TemplateError
+
+logger = logging.getLogger(__name__)
+
+
+class TemplateRenderer:
+    """Jinja2 template renderer for LLM prompts"""
+    
+    def __init__(self):
+        self.env = Environment(
+            loader=BaseLoader(),
+            # Enable safe variable substitution
+            autoescape=False,
+            # Custom delimiters to avoid conflicts with common markdown syntax
+            variable_start_string='{{',
+            variable_end_string='}}',
+            block_start_string='{%',
+            block_end_string='%}',
+            comment_start_string='{#',
+            comment_end_string='#}',
+            # Keep linebreaks
+            keep_trailing_newline=True,
+            # Remove unnecessary whitespace
+            trim_blocks=True,
+            lstrip_blocks=True
+        )
+    
+    def render_template(self, template_string: str, variables: Dict[str, Any]) -> str:
+        """
+        Render a Jinja2 template string with provided variables
+        
+        Args:
+            template_string: The template string with Jinja2 syntax
+            variables: Dictionary of variables to substitute
+            
+        Returns:
+            Rendered template string
+            
+        Raises:
+            TemplateError: If template rendering fails
+        """
+        try:
+            template = self.env.from_string(template_string)
+            rendered = template.render(**variables)
+            logger.debug(f"Template rendered successfully with variables: {list(variables.keys())}")
+            return rendered
+        except TemplateError as e:
+            logger.error(f"Template rendering failed: {e}")
+            logger.error(f"Template: {template_string[:200]}...")
+            logger.error(f"Variables: {variables}")
+            raise
+        except Exception as e:
+            logger.error(f"Unexpected error during template rendering: {e}")
+            raise TemplateError(f"Template rendering failed: {e}")
+    
+    def render_system_prompt(self, template_string: str, variables: Dict[str, Any]) -> str:
+        """
+        Render system prompt template
+        
+        Args:
+            template_string: System prompt template
+            variables: Variables for substitution
+            
+        Returns:
+            Rendered system prompt
+        """
+        return self.render_template(template_string, variables)
+    
+    def render_user_prompt(self, template_string: str, variables: Dict[str, Any]) -> str:
+        """
+        Render user prompt template
+        
+        Args:
+            template_string: User prompt template  
+            variables: Variables for substitution
+            
+        Returns:
+            Rendered user prompt
+        """
+        return self.render_template(template_string, variables)
+
+
+# Global template renderer instance
+template_renderer = TemplateRenderer()
+
+
+def render_prompt_template(template_string: str, variables: Dict[str, Any]) -> str:
+    """
+    Convenience function to render prompt templates
+    
+    Args:
+        template_string: Template string with Jinja2 syntax
+        variables: Dictionary of variables to substitute
+        
+    Returns:
+        Rendered template string
+    """
+    return template_renderer.render_template(template_string, variables)