Address review feedback

Use the VERSION attribute exposed by Billiard to decide whether to
import ExceptionWithTraceback.

Add a test for a failing task and check that the exceptions' type
and message are preserved.

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

@@ -66,13 +66,6 @@ def add(x, y):
 from billiard.einfo import ExceptionInfo
 from celery import signals  # pylint: disable=no-name-in-module
 
-try:
-    from billiard.einfo import (  # pylint: disable=no-name-in-module
-        ExceptionWithTraceback,
-    )
-except ImportError:
-    ExceptionWithTraceback = None
-
 from opentelemetry import trace
 from opentelemetry.instrumentation.celery import utils
 from opentelemetry.instrumentation.celery.package import _instruments
@@ -84,6 +77,8 @@ def add(x, y):
 from opentelemetry.semconv.trace import SpanAttributes
 from opentelemetry.trace.status import Status, StatusCode
 
+ExceptionWithTraceback = utils.import_exception_with_traceback()
+
 logger = logging.getLogger(__name__)
 
 # Task operations

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

@@ -15,6 +15,7 @@
 import logging
 
 from celery import registry  # pylint: disable=no-name-in-module
+from billiard import VERSION
 
 from opentelemetry.semconv.trace import SpanAttributes
 
@@ -47,6 +48,15 @@
 )
 
 
+def import_exception_with_traceback():
+    if VERSION >= (4, 0, 1):
+        from billiard.einfo import ExceptionWithTraceback
+
+        return ExceptionWithTraceback
+
+    return None
+
+
 # pylint:disable=too-many-branches
 def set_attributes_from_context(span, context):
     """Helper to extract meta values from a Celery Context"""

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

@@ -24,6 +24,15 @@ class Config:
 app.config_from_object(Config)
 
 
+class CustomError(Exception):
+    pass
+
+
 @app.task
 def task_add(num_a, num_b):
     return num_a + num_b
+
+
+@app.task
+def task_raises():
+    raise CustomError("The task failed!")

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

@@ -18,9 +18,9 @@
 from opentelemetry.instrumentation.celery import CeleryInstrumentor
 from opentelemetry.semconv.trace import SpanAttributes
 from opentelemetry.test.test_base import TestBase
-from opentelemetry.trace import SpanKind
+from opentelemetry.trace import SpanKind, StatusCode
 
-from .celery_test_tasks import app, task_add
+from .celery_test_tasks import app, task_add, task_raises
 
 
 class TestCeleryInstrumentation(TestBase):
@@ -66,6 +66,10 @@ def test_task(self):
             },
         )
 
+        self.assertEqual(consumer.status.status_code, StatusCode.UNSET)
+
+        self.assertEqual(0, len(consumer.events))
+
         self.assertEqual(
             producer.name, "apply_async/tests.celery_test_tasks.task_add"
         )
@@ -84,6 +88,70 @@ def test_task(self):
         self.assertEqual(consumer.parent.span_id, producer.context.span_id)
         self.assertEqual(consumer.context.trace_id, producer.context.trace_id)
 
+    def test_task_raises(self):
+        CeleryInstrumentor().instrument()
+
+        result = task_raises.delay()
+
+        timeout = time.time() + 60 * 1  # 1 minutes from now
+        while not result.ready():
+            if time.time() > timeout:
+                break
+            time.sleep(0.05)
+
+        spans = self.sorted_spans(self.memory_exporter.get_finished_spans())
+        self.assertEqual(len(spans), 2)
+
+        consumer, producer = spans
+
+        self.assertEqual(
+            consumer.name, "run/tests.celery_test_tasks.task_raises"
+        )
+        self.assertEqual(consumer.kind, SpanKind.CONSUMER)
+        self.assertSpanHasAttributes(
+            consumer,
+            {
+                "celery.action": "run",
+                "celery.state": "FAILURE",
+                SpanAttributes.MESSAGING_DESTINATION: "celery",
+                "celery.task_name": "tests.celery_test_tasks.task_raises",
+            },
+        )
+
+        self.assertEqual(consumer.status.status_code, StatusCode.ERROR)
+
+        self.assertEqual(1, len(consumer.events))
+        event = consumer.events[0]
+
+        self.assertIn(SpanAttributes.EXCEPTION_STACKTRACE, event.attributes)
+
+        self.assertEqual(
+            event.attributes[SpanAttributes.EXCEPTION_TYPE], "CustomError"
+        )
+
+        self.assertEqual(
+            event.attributes[SpanAttributes.EXCEPTION_MESSAGE],
+            "The task failed!",
+        )
+
+        self.assertEqual(
+            producer.name, "apply_async/tests.celery_test_tasks.task_raises"
+        )
+        self.assertEqual(producer.kind, SpanKind.PRODUCER)
+        self.assertSpanHasAttributes(
+            producer,
+            {
+                "celery.action": "apply_async",
+                "celery.task_name": "tests.celery_test_tasks.task_raises",
+                SpanAttributes.MESSAGING_DESTINATION_KIND: "queue",
+                SpanAttributes.MESSAGING_DESTINATION: "celery",
+            },
+        )
+
+        self.assertNotEqual(consumer.parent, producer.context)
+        self.assertEqual(consumer.parent.span_id, producer.context.span_id)
+        self.assertEqual(consumer.context.trace_id, producer.context.trace_id)
+
     def test_uninstrument(self):
         CeleryInstrumentor().instrument()
         CeleryInstrumentor().uninstrument()