Introduce MemoryEvents to monitor their usage (#3098)

* feat: emit events about memory usage

* test: add tests about memory events usage

* fixed linter issues

* test: use scoped_handlers while listener Memory events

src/crewai/utilities/events/memory_events.py

@@ -0,0 +1,78 @@
+from typing import Any, Dict, Optional
+
+from crewai.utilities.events.base_events import BaseEvent
+
+
+class MemoryQueryStartedEvent(BaseEvent):
+    """Event emitted when a memory query is started"""
+
+    type: str = "memory_query_started"
+    query: str
+    limit: int
+    score_threshold: Optional[float] = None
+
+
+class MemoryQueryCompletedEvent(BaseEvent):
+    """Event emitted when a memory query is completed successfully"""
+
+    type: str = "memory_query_completed"
+    query: str
+    results: Any
+    limit: int
+    score_threshold: Optional[float] = None
+    query_time_ms: float
+
+
+class MemoryQueryFailedEvent(BaseEvent):
+    """Event emitted when a memory query fails"""
+
+    type: str = "memory_query_failed"
+    query: str
+    limit: int
+    score_threshold: Optional[float] = None
+    error: str
+
+
+class MemorySaveStartedEvent(BaseEvent):
+    """Event emitted when a memory save operation is started"""
+
+    type: str = "memory_save_started"
+    value: Optional[str] = None
+    metadata: Optional[Dict[str, Any]] = None
+    agent_role: Optional[str] = None
+
+
+class MemorySaveCompletedEvent(BaseEvent):
+    """Event emitted when a memory save operation is completed successfully"""
+
+    type: str = "memory_save_completed"
+    value: str
+    metadata: Optional[Dict[str, Any]] = None
+    agent_role: Optional[str] = None
+    save_time_ms: float
+
+
+class MemorySaveFailedEvent(BaseEvent):
+    """Event emitted when a memory save operation fails"""
+
+    type: str = "memory_save_failed"
+    value: Optional[str] = None
+    metadata: Optional[Dict[str, Any]] = None
+    agent_role: Optional[str] = None
+    error: str
+
+
+class MemoryRetrievalStartedEvent(BaseEvent):
+    """Event emitted when memory retrieval for a task prompt starts"""
+
+    type: str = "memory_retrieval_started"
+    task_id: Optional[str] = None
+
+
+class MemoryRetrievalCompletedEvent(BaseEvent):
+    """Event emitted when memory retrieval for a task prompt completes successfully"""
+
+    type: str = "memory_retrieval_completed"
+    task_id: Optional[str] = None
+    memory_content: str
+    retrieval_time_ms: float