Feat: Agent Token or Request Limiting (#2041)

* Update routes.py, added token and request limits to create/update agent operations

* added usage limit check to api endpoints

cannot create agents with usage limit right now that will be implemented

* implemented api limiting as either token limiting or request limiting modes

* minor typo & bug fix

application/api/answer/routes/base.py

@@ -3,7 +3,7 @@ import json
 import logging
 from typing import Any, Dict, Generator, List, Optional
 
-from flask import Response
+from flask import Response, make_response, jsonify
 from flask_restx import Namespace
 
 from application.api.answer.services.conversation_service import ConversationService
@@ -25,6 +25,7 @@ class BaseAnswerResource:
     def __init__(self):
         mongo = MongoDB.get_client()
         db = mongo[settings.MONGO_DB_NAME]
+        self.db = db
         self.user_logs_collection = db["user_logs"]
         self.gpt_model = get_gpt_model()
         self.conversation_service = ConversationService()
@@ -40,6 +41,88 @@ class BaseAnswerResource:
             return missing_fields
         return None
 
+    def check_usage(
+            self, agent_config: Dict
+    ) -> Optional[Response]:
+        """Check if there is a usage limit and if it is exceeded
+
+        Args:
+            agent_config: The config dict of agent instance
+
+        Returns:
+            None or Response if either of limits exceeded.
+        
+        """
+        api_key = agent_config.get("user_api_key")
+        if not api_key:
+            return None
+        
+        agents_collection = self.db["agents"]
+        agent = agents_collection.find_one({"key": api_key})
+
+        if not agent:
+            return make_response(
+                jsonify(
+                    {
+                        "success": False,
+                        "message": "Invalid API key."
+                    }
+                ),
+                401
+            )
+
+        limited_token_mode = agent.get("limited_token_mode", False)
+        limited_request_mode = agent.get("limited_request_mode", False)
+        token_limit = int(agent.get("token_limit", settings.DEFAULT_AGENT_LIMITS["token_limit"]))
+        request_limit = int(agent.get("request_limit", settings.DEFAULT_AGENT_LIMITS["request_limit"]))
+
+        token_usage_collection = self.db["token_usage"]
+
+        end_date = datetime.datetime.now()
+        start_date = end_date - datetime.timedelta(hours=24)
+
+        match_query = {
+            "timestamp": {"$gte": start_date, "$lte": end_date},
+            "api_key": api_key
+        }
+        
+        if limited_token_mode:
+            token_pipeline = [
+                {"$match": match_query},
+                {
+                    "$group": {
+                        "_id": None,
+                        "total_tokens": {"$sum": {"$add": ["$prompt_tokens", "$generated_tokens"]}}
+                    }
+                }
+            ]
+            token_result = list(token_usage_collection.aggregate(token_pipeline))
+            daily_token_usage = token_result[0]["total_tokens"] if token_result else 0
+        else:
+            daily_token_usage = 0
+
+        if limited_request_mode:
+            daily_request_usage = token_usage_collection.count_documents(match_query)
+        else:
+            daily_request_usage = 0
+
+        if not limited_token_mode and not limited_request_mode:
+            return None
+        elif limited_token_mode and token_limit > daily_token_usage:
+            return None
+        elif limited_request_mode and request_limit > daily_request_usage:
+            return None
+
+        return make_response(
+            jsonify(
+                {
+                    "success": False,
+                    "message": "Exceeding usage limit, please try again later."
+                }
+            ),
+            429, # too many requests
+        )
+
     def complete_stream(
         self,
         question: str,