refactor: Improve telemetry span tracking in EventListener

- Remove `execution_span` from Task class
- Add `execution_spans` dictionary to EventListener to track spans
- Update task event handlers to use new span tracking mechanism
- Simplify span management across task lifecycle events

src/crewai/task.py

@@ -144,9 +144,6 @@ class Task(BaseModel):
     end_time: Optional[datetime.datetime] = Field(
         default=None, description="End time of the task execution"
     )
-    execution_span: Optional[Any] = Field(
-        default=None, description="Open Telemetry Span of the task execution"
-    )
 
     @field_validator("guardrail")
     @classmethod

src/crewai/utilities/events/event_listener.py

@@ -1,5 +1,7 @@
-from pydantic import PrivateAttr
+from typing import Any, Dict
+from pydantic import Field, PrivateAttr
 
+from crewai.task import Task
 from crewai.telemetry.telemetry import Telemetry
 from crewai.utilities import Logger
 from crewai.utilities.constants import EMITTER_COLOR
@@ -37,6 +39,7 @@ class EventListener(BaseEventListener):
     _instance = None
     _telemetry: Telemetry = PrivateAttr(default_factory=lambda: Telemetry())
     logger = Logger(verbose=True, default_color=EMITTER_COLOR)
+    execution_spans: Dict[Task, Any] = Field(default_factory=dict)
 
     def __new__(cls):
         if cls._instance is None:
@@ -49,6 +52,7 @@ class EventListener(BaseEventListener):
             super().__init__()
             self._telemetry = Telemetry()
             self._telemetry.set_tracer()
+            self.execution_spans = {}
             self._initialized = True
 
     # ----------- CREW EVENTS -----------
@@ -132,7 +136,8 @@ class EventListener(BaseEventListener):
         @crewai_event_bus.on(TaskStartedEvent)
         def on_task_started(source, event: TaskStartedEvent):
             span = self._telemetry.task_started(crew=source.agent.crew, task=source)
-            source.execution_span = span
+            self.execution_spans[source] = span
+
             self.logger.log(
                 f"📋 Task started: {source.description}",
                 event.timestamp,
@@ -140,24 +145,22 @@ class EventListener(BaseEventListener):
 
         @crewai_event_bus.on(TaskCompletedEvent)
         def on_task_completed(source, event: TaskCompletedEvent):
-            if source.execution_span:
-                self._telemetry.task_ended(
-                    source.execution_span, source, source.agent.crew
-                )
+            span = self.execution_spans.get(source)
+            if span:
+                self._telemetry.task_ended(span, source, source.agent.crew)
             self.logger.log(
                 f"✅ Task completed: {source.description}",
                 event.timestamp,
             )
-            source.execution_span = None
+            self.execution_spans[source] = None
 
         @crewai_event_bus.on(TaskFailedEvent)
         def on_task_failed(source, event: TaskFailedEvent):
-            if source.execution_span:
+            span = self.execution_spans.get(source)
+            if span:
                 if source.agent and source.agent.crew:
-                    self._telemetry.task_ended(
-                        source.execution_span, source, source.agent.crew
-                    )
-                source.execution_span = None
+                    self._telemetry.task_ended(span, source, source.agent.crew)
+                self.execution_spans[source] = None
             self.logger.log(
                 f"❌ Task failed: {source.description}",
                 event.timestamp,