Do not create a span when task is triggered by Celery Beat (#2510)

We create a span for submitting a Celery task for execution (when apply_async() is called). In cases where web frameworks are calling apply_async() this is fine, because the web framework created a transaction where the span is attached.

When Celery Beat wakes up and is calling apply_async() this is not good, because there is no transaction and then the span ID of the newly created span will be given to the task as parent_span_id leading to orphaned transactions.

So in case apply_async() is called by Celery Beat, we do not create a span for submitting the task for execution.

sentry_sdk/integrations/celery.py

@@ -30,6 +30,7 @@
     from typing import TypeVar
     from typing import Union
 
+    from sentry_sdk.tracing import Span
     from sentry_sdk._types import EventProcessor, Event, Hint, ExcInfo
 
     F = TypeVar("F", bound=Callable[..., Any])
@@ -133,6 +134,16 @@ def _now_seconds_since_epoch():
     return time.time()
 
 
+class NoOpMgr:
+    def __enter__(self):
+        # type: () -> None
+        return None
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        # type: (Any, Any, Any) -> None
+        return None
+
+
 def _wrap_apply_async(f):
     # type: (F) -> F
     @wraps(f)
@@ -154,11 +165,26 @@ def apply_async(*args, **kwargs):
         if not propagate_traces:
             return f(*args, **kwargs)
 
-        with hub.start_span(
-            op=OP.QUEUE_SUBMIT_CELERY, description=args[0].name
-        ) as span:
+        try:
+            task_started_from_beat = args[1][0] == "BEAT"
+        except IndexError:
+            task_started_from_beat = False
+
+        task = args[0]
+
+        span_mgr = (
+            hub.start_span(op=OP.QUEUE_SUBMIT_CELERY, description=task.name)
+            if not task_started_from_beat
+            else NoOpMgr()
+        )  # type: Union[Span, NoOpMgr]
+
+        with span_mgr as span:
             with capture_internal_exceptions():
-                headers = dict(hub.iter_trace_propagation_headers(span))
+                headers = (
+                    dict(hub.iter_trace_propagation_headers(span))
+                    if span is not None
+                    else {}
+                )
                 if integration.monitor_beat_tasks:
                     headers.update(
                         {

tests/integrations/celery/test_celery.py

@@ -3,7 +3,11 @@
 import pytest
 
 from sentry_sdk import Hub, configure_scope, start_transaction, get_current_span
-from sentry_sdk.integrations.celery import CeleryIntegration, _get_headers
+from sentry_sdk.integrations.celery import (
+    CeleryIntegration,
+    _get_headers,
+    _wrap_apply_async,
+)
 
 from sentry_sdk._compat import text_type
 
@@ -555,3 +559,37 @@ def dummy_task(self, message):
             headers={"sentry-propagate-traces": False},
         ).get()
         assert transaction_trace_id != task_transaction_id
+
+
+def test_apply_async_manually_span(sentry_init):
+    sentry_init(
+        integrations=[CeleryIntegration()],
+    )
+
+    def dummy_function(*args, **kwargs):
+        headers = kwargs.get("headers")
+        assert "sentry-trace" in headers
+        assert "baggage" in headers
+
+    wrapped = _wrap_apply_async(dummy_function)
+    wrapped(mock.MagicMock(), (), headers={})
+
+
+def test_apply_async_from_beat_no_span(sentry_init):
+    sentry_init(
+        integrations=[CeleryIntegration()],
+    )
+
+    def dummy_function(*args, **kwargs):
+        headers = kwargs.get("headers")
+        assert "sentry-trace" not in headers
+        assert "baggage" not in headers
+
+    wrapped = _wrap_apply_async(dummy_function)
+    wrapped(
+        mock.MagicMock(),
+        [
+            "BEAT",
+        ],
+        headers={},
+    )