Fix telemetry singleton pattern to respect dynamic environment variables (#2946)

* Fix telemetry singleton pattern to respect dynamic environment variables

- Modified Telemetry.__init__ to prevent re-initialization with _initialized flag
- Updated _safe_telemetry_operation to check _is_telemetry_disabled() dynamically
- Added comprehensive tests for environment variables set after singleton creation
- Fixed singleton contamination in existing tests by adding proper reset
- Resolves issue #2945 where CREWAI_DISABLE_TELEMETRY=true was ignored when set after import

Co-Authored-By: João <joao@crewai.com>

* Implement code review improvements

- Move _initialized flag to __new__ method for better encapsulation
- Add type hints to _safe_telemetry_operation method
- Consolidate telemetry execution checks into _should_execute_telemetry helper
- Add pytest fixtures to reduce test setup redundancy
- Enhanced documentation for singleton behavior

Co-Authored-By: João <joao@crewai.com>

* Fix mypy type-checker errors

- Add explicit bool type annotation to _initialized field
- Fix return value in task_started method to not return _safe_telemetry_operation result
- Simplify initialization logic to set _initialized once in __init__

Co-Authored-By: João <joao@crewai.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: João <joao@crewai.com>
Co-authored-by: Lorenze Jay <63378463+lorenzejay@users.noreply.github.com>

src/crewai/telemetry/telemetry.py

@@ -8,7 +8,7 @@ import platform
 import warnings
 from contextlib import contextmanager
 from importlib.metadata import version
-from typing import TYPE_CHECKING, Any, Optional
+from typing import TYPE_CHECKING, Any, Callable, Optional
 import threading
 
 from opentelemetry import trace
@@ -73,11 +73,16 @@ class Telemetry:
             with cls._lock:
                 if cls._instance is None:
                     cls._instance = super(Telemetry, cls).__new__(cls)
+                    cls._instance._initialized = False
         return cls._instance
 
     def __init__(self) -> None:
+        if hasattr(self, '_initialized') and self._initialized:
+            return
+        
         self.ready: bool = False
         self.trace_set: bool = False
+        self._initialized: bool = True
 
         if self._is_telemetry_disabled():
             return
@@ -113,6 +118,10 @@ class Telemetry:
             or os.getenv("CREWAI_DISABLE_TELEMETRY", "false").lower() == "true"
         )
 
+    def _should_execute_telemetry(self) -> bool:
+        """Check if telemetry operations should be executed."""
+        return self.ready and not self._is_telemetry_disabled()
+
     def set_tracer(self):
         if self.ready and not self.trace_set:
             try:
@@ -123,8 +132,9 @@ class Telemetry:
                 self.ready = False
                 self.trace_set = False
 
-    def _safe_telemetry_operation(self, operation):
+    def _safe_telemetry_operation(self, operation: Callable[[], None]) -> None:
-        if not self.ready:
+        """Execute telemetry operation safely, checking both readiness and environment variables."""
+        if not self._should_execute_telemetry():
             return
         try:
             operation()
@@ -423,7 +433,8 @@ class Telemetry:
 
             return span
 
-        return self._safe_telemetry_operation(operation)
+        self._safe_telemetry_operation(operation)
+        return None
 
     def task_ended(self, span: Span, task: Task, crew: Crew):
         """Records the completion of a task execution in a crew.
@@ -773,7 +784,8 @@ class Telemetry:
             return span
 
         if crew.share_crew:
-            return self._safe_telemetry_operation(operation)
+            self._safe_telemetry_operation(operation)
+            return operation()
         return None
 
     def end_crew(self, crew, final_string_output):

tests/telemetry/test_telemetry.py

@@ -9,6 +9,14 @@ from crewai.telemetry import Telemetry
 from opentelemetry import trace
 
 
+@pytest.fixture(autouse=True)
+def cleanup_telemetry():
+    """Automatically clean up Telemetry singleton between tests."""
+    Telemetry._instance = None
+    yield
+    Telemetry._instance = None
+
+
 @pytest.mark.parametrize(
     "env_var,value,expected_ready",
     [

tests/telemetry/test_telemetry_disable.py

@@ -1,11 +1,19 @@
 import os
-from unittest.mock import patch
+from unittest.mock import patch, MagicMock
 
 import pytest
 
 from crewai.telemetry import Telemetry
 
 
+@pytest.fixture(autouse=True)
+def cleanup_telemetry():
+    """Automatically clean up Telemetry singleton between tests."""
+    Telemetry._instance = None
+    yield
+    Telemetry._instance = None
+
+
 @pytest.mark.parametrize("env_var,value,expected_ready", [
     ("OTEL_SDK_DISABLED", "true", False),
     ("OTEL_SDK_DISABLED", "TRUE", False),
@@ -28,3 +36,59 @@ def test_telemetry_enabled_by_default():
         with patch("crewai.telemetry.telemetry.TracerProvider"):
             telemetry = Telemetry()
             assert telemetry.ready is True
+
+
+def test_telemetry_disable_after_singleton_creation():
+    """Test that telemetry operations are disabled when env var is set after singleton creation."""
+    with patch.dict(os.environ, {}, clear=True):
+        with patch("crewai.telemetry.telemetry.TracerProvider"):
+            telemetry = Telemetry()
+            assert telemetry.ready is True
+            
+            mock_operation = MagicMock()
+            telemetry._safe_telemetry_operation(mock_operation)
+            mock_operation.assert_called_once()
+            
+            mock_operation.reset_mock()
+            
+            os.environ['CREWAI_DISABLE_TELEMETRY'] = 'true'
+            
+            telemetry._safe_telemetry_operation(mock_operation)
+            mock_operation.assert_not_called()
+
+
+def test_telemetry_disable_with_multiple_instances():
+    """Test that multiple telemetry instances respect dynamically changed env vars."""
+    with patch.dict(os.environ, {}, clear=True):
+        with patch("crewai.telemetry.telemetry.TracerProvider"):
+            telemetry1 = Telemetry()
+            assert telemetry1.ready is True
+            
+            os.environ['CREWAI_DISABLE_TELEMETRY'] = 'true'
+            
+            telemetry2 = Telemetry()
+            assert telemetry2 is telemetry1
+            assert telemetry2.ready is True
+            
+            mock_operation = MagicMock()
+            telemetry2._safe_telemetry_operation(mock_operation)
+            mock_operation.assert_not_called()
+
+
+def test_telemetry_otel_sdk_disabled_after_creation():
+    """Test that OTEL_SDK_DISABLED also works when set after singleton creation."""
+    with patch.dict(os.environ, {}, clear=True):
+        with patch("crewai.telemetry.telemetry.TracerProvider"):
+            telemetry = Telemetry()
+            assert telemetry.ready is True
+            
+            mock_operation = MagicMock()
+            telemetry._safe_telemetry_operation(mock_operation)
+            mock_operation.assert_called_once()
+            
+            mock_operation.reset_mock()
+            
+            os.environ['OTEL_SDK_DISABLED'] = 'true'
+            
+            telemetry._safe_telemetry_operation(mock_operation)
+            mock_operation.assert_not_called()