fix(client-reports): Record lost sample_rate events only if tracing is enabled (#1268)

Author: sl0thentr0py

CHANGELOG.md

@@ -23,6 +23,7 @@ A major release `N` implies the previous release `N-1` will no longer receive up
 ## Unreleased
 
 - Fix django legacy url resolver regex substitution due to upstream CVE-2021-44420 fix #1272
+- Record lost `sample_rate` events only if tracing is enabled
 
 ## 1.5.0
 

sentry_sdk/tracing.py

@@ -543,24 +543,24 @@ def finish(self, hub=None):
         hub = hub or self.hub or sentry_sdk.Hub.current
         client = hub.client
 
+        if client is None:
+            # We have no client and therefore nowhere to send this transaction.
+            return None
+
         # This is a de facto proxy for checking if sampled = False
         if self._span_recorder is None:
             logger.debug("Discarding transaction because sampled = False")
 
             # This is not entirely accurate because discards here are not
             # exclusively based on sample rate but also traces sampler, but
             # we handle this the same here.
-            if client and client.transport:
+            if client.transport and has_tracing_enabled(client.options):
                 client.transport.record_lost_event(
                     "sample_rate", data_category="transaction"
                 )
 
             return None
 
-        if client is None:
-            # We have no client and therefore nowhere to send this transaction.
-            return None
-
         if not self.name:
             logger.warning(
                 "Transaction has no name, falling back to `<unlabeled transaction>`."

sentry_sdk/tracing_utils.py

@@ -109,7 +109,7 @@ def has_tracing_enabled(options):
     # type: (Dict[str, Any]) -> bool
     """
     Returns True if either traces_sample_rate or traces_sampler is
-    non-zero/defined, False otherwise.
+    defined, False otherwise.
     """
 
     return bool(

tests/tracing/test_sampling.py

@@ -284,3 +284,61 @@ def test_warns_and_sets_sampled_to_false_on_invalid_traces_sampler_return_value(
         transaction = start_transaction(name="dogpark")
         logger.warning.assert_any_call(StringContaining("Given sample rate is invalid"))
         assert transaction.sampled is False
+
+
+@pytest.mark.parametrize(
+    "traces_sample_rate,sampled_output,reports_output",
+    [
+        (None, False, []),
+        (0.0, False, [("sample_rate", "transaction")]),
+        (1.0, True, []),
+    ],
+)
+def test_records_lost_event_only_if_traces_sample_rate_enabled(
+    sentry_init, traces_sample_rate, sampled_output, reports_output, monkeypatch
+):
+    reports = []
+
+    def record_lost_event(reason, data_category=None, item=None):
+        reports.append((reason, data_category))
+
+    sentry_init(traces_sample_rate=traces_sample_rate)
+
+    monkeypatch.setattr(
+        Hub.current.client.transport, "record_lost_event", record_lost_event
+    )
+
+    transaction = start_transaction(name="dogpark")
+    assert transaction.sampled is sampled_output
+    transaction.finish()
+
+    assert reports == reports_output
+
+
+@pytest.mark.parametrize(
+    "traces_sampler,sampled_output,reports_output",
+    [
+        (None, False, []),
+        (lambda _x: 0.0, False, [("sample_rate", "transaction")]),
+        (lambda _x: 1.0, True, []),
+    ],
+)
+def test_records_lost_event_only_if_traces_sampler_enabled(
+    sentry_init, traces_sampler, sampled_output, reports_output, monkeypatch
+):
+    reports = []
+
+    def record_lost_event(reason, data_category=None, item=None):
+        reports.append((reason, data_category))
+
+    sentry_init(traces_sampler=traces_sampler)
+
+    monkeypatch.setattr(
+        Hub.current.client.transport, "record_lost_event", record_lost_event
+    )
+
+    transaction = start_transaction(name="dogpark")
+    assert transaction.sampled is sampled_output
+    transaction.finish()
+
+    assert reports == reports_output