Refactoring task cache to be a tool (#50)

* Refactoring task cache to be a tool

The previous implementation of the task caching system was early exiting
the agent executor due to the fact it was returning an AgentFinish object.

This now refactors it to use a cache specific tool that is dynamically
added and forced into the agent in case of a task execution that was
already executed with the same input.

crewai/agents/output_parser.py

@@ -6,6 +6,7 @@ from langchain_core.agents import AgentAction, AgentFinish
 from langchain_core.exceptions import OutputParserException
 
 from .cache_handler import CacheHandler
+from .cache_hit import CacheHit
 from .tools_handler import ToolsHandler
 
 FINAL_ANSWER_ACTION = "Final Answer:"
@@ -47,17 +48,13 @@ class CrewAgentOutputParser(ReActSingleInputOutputParser):
     tools_handler: ToolsHandler
     cache: CacheHandler
 
-    def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
-        includes_answer = FINAL_ANSWER_ACTION in text
+    def parse(self, text: str) -> Union[AgentAction, AgentFinish, CacheHit]:
+        FINAL_ANSWER_ACTION in text
         regex = (
             r"Action\s*\d*\s*:[\s]*(.*?)[\s]*Action\s*\d*\s*Input\s*\d*\s*:[\s]*(.*)"
         )
         action_match = re.search(regex, text, re.DOTALL)
         if action_match:
-            if includes_answer:
-                raise OutputParserException(
-                    f"{FINAL_ANSWER_AND_PARSABLE_ACTION_ERROR_MESSAGE}: {text}"
-                )
             action = action_match.group(1).strip()
             action_input = action_match.group(2)
             tool_input = action_input.strip(" ")
@@ -76,6 +73,7 @@ class CrewAgentOutputParser(ReActSingleInputOutputParser):
 
             result = self.cache.read(action, tool_input)
             if result:
-                return AgentFinish({"output": result}, text)
+                action = AgentAction(action, tool_input, text)
+                return CacheHit(action=action, cache=self.cache)
 
         return super().parse(text)