feat(auth): add extrnal auth introspect api interface

apps/authentication/backend/infra/api_key_introspect_handler.py

@@ -0,0 +1,52 @@
+from typing import Dict, Any
+import httpx
+from fastapi import HTTPException
+from common.config.app_settings import app_settings
+from common.log.log_utils import log_entry_exit_async
+from common.log.module_logger import ModuleLogger
+
+
+class ApiKeyIntrospectHandler:
+    """
+    Freeleaps Auth Service API Key Introspect Handle
+    """
+
+    def __init__(self) -> None:
+        self.module_logger = ModuleLogger(sender_id=ApiKeyIntrospectHandler.__name__)
+        self.auth_service_base = app_settings.AUTH_SERVICE_ENDPOINT
+
+
+    @log_entry_exit_async
+    async def api_key_introspect(self, api_key: str) -> Dict[str, Any]:
+        """
+        Introspect API key by calling external auth service
+        
+        Args:
+            api_key: The API key to introspect
+            
+        Returns:
+            Dictionary containing the API key details
+            
+        Raises:
+            HTTPException: If the external service call fails
+        """
+        api_url = self.auth_service_base + "introspect_api_key"
+        await self.module_logger.log_info(f"Starting API Key validation for key: {api_key[:8]}...")
+        
+        async with httpx.AsyncClient() as client:
+            response = await client.post(
+                api_url,
+                json={"api_key": api_key}
+            )
+            
+            if response.status_code != 200:
+                error_detail = response.json() if response.content else {"error": "Unknown error"}
+                await self.module_logger.log_error(f"API Key validation failed - Status: {response.status_code}, Error: {error_detail}")
+                raise HTTPException(
+                    status_code=response.status_code,
+                    detail=error_detail
+                )
+            
+            validation_result = response.json()
+            await self.module_logger.log_info(f"API Key validation successful - Active: {validation_result.get('active', False)}")
+            return validation_result