Do not keep task id reference indefinitely

Author: rbagd

instrumentation/opentelemetry-instrumentation-celery/src/opentelemetry/instrumentation/celery/__init__.py

@@ -362,6 +362,7 @@ def _record_histograms(self, task_id, metric_attributes):
             self.task_id_to_start_time.get(task_id),
             attributes=metric_attributes,
         )
+        self.task_id_to_start_time.pop(task_id, None)
 
     def create_celery_metrics(self, meter) -> None:
         self.metrics = {

instrumentation/opentelemetry-instrumentation-celery/tests/test_metrics.py

@@ -42,6 +42,8 @@ def test_basic_metric(self):
         task_runtime_estimated = (default_timer() - start_time) * 1000
 
         metrics = self.get_metrics()
+        self.assertEqual(CeleryInstrumentor().task_id_to_start_time, {})
+
         CeleryInstrumentor().uninstrument()
         self.assertEqual(len(metrics), 1)