Add support for anonymous tasks (#1407)

CHANGELOG.md

@@ -21,6 +21,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1730](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1730))
 - Make ASGI request span attributes available for `start_span`. 
   ([#1762](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1762))
+- `opentelemetry-instrumentation-celery` Add support for anonymous tasks.
+  ([#1407](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/1407)
+
 
 ### Fixed
 

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

@@ -183,10 +183,17 @@ def _trace_before_publish(self, *args, **kwargs):
         task = utils.retrieve_task_from_sender(kwargs)
         task_id = utils.retrieve_task_id_from_message(kwargs)
 
-        if task is None or task_id is None:
+        if task_id is None:
             return
 
-        operation_name = f"{_TASK_APPLY_ASYNC}/{task.name}"
+        if task is None:
+            # task is an anonymous task send using send_task or using canvas workflow
+            # Signatures() to send to a task not in the current processes dependency
+            # tree
+            task_name = kwargs.get("sender", "unknown")
+        else:
+            task_name = task.name
+        operation_name = f"{_TASK_APPLY_ASYNC}/{task_name}"
         span = self._tracer.start_span(
             operation_name, kind=trace.SpanKind.PRODUCER
         )
@@ -195,7 +202,7 @@ def _trace_before_publish(self, *args, **kwargs):
         if span.is_recording():
             span.set_attribute(_TASK_TAG_KEY, _TASK_APPLY_ASYNC)
             span.set_attribute(SpanAttributes.MESSAGING_MESSAGE_ID, task_id)
-            span.set_attribute(_TASK_NAME_KEY, task.name)
+            span.set_attribute(_TASK_NAME_KEY, task_name)
             utils.set_attributes_from_context(span, kwargs)
 
         activation = trace.use_span(span, end_on_exit=True)

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

@@ -132,6 +132,8 @@ def attach_span(task, task_id, span, is_publish=False):
     NOTE: We cannot test for this well yet, because we do not run a celery worker,
     and cannot run `task.apply_async()`
     """
+    if task is None:
+        return
     span_dict = getattr(task, CTX_KEY, None)
     if span_dict is None:
         span_dict = {}

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

@@ -36,6 +36,7 @@ def tearDown(self):
         CeleryInstrumentor().uninstrument()
         self._worker.stop()
         self._thread.join()
+        CeleryInstrumentor().uninstrument()
 
     def test_task(self):
         CeleryInstrumentor().instrument()
@@ -97,3 +98,52 @@ def test_uninstrument(self):
 
         spans = self.memory_exporter.get_finished_spans()
         self.assertEqual(len(spans), 0)
+
+
+class TestCelerySignatureTask(TestBase):
+    def setUp(self):
+        super().setUp()
+
+        def start_app(*args, **kwargs):
+            # Add an additional task that will not be registered with parent thread
+            @app.task
+            def hidden_task(num_a):
+                return num_a * 2
+
+            self._worker = app.Worker(app=app, pool="solo", concurrency=1)
+            return self._worker.start(*args, **kwargs)
+
+        self._thread = threading.Thread(target=start_app)
+        self._worker = app.Worker(app=app, pool="solo", concurrency=1)
+        self._thread.daemon = True
+        self._thread.start()
+
+    def tearDown(self):
+        super().tearDown()
+        self._worker.stop()
+        self._thread.join()
+        CeleryInstrumentor().uninstrument()
+
+    def test_hidden_task(self):
+        # no-op since already instrumented
+        CeleryInstrumentor().instrument()
+
+        res = app.signature("tests.test_tasks.hidden_task", (2,)).apply_async()
+        while not res.ready():
+            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.test_tasks.hidden_task")
+        self.assertEqual(consumer.kind, SpanKind.CONSUMER)
+
+        self.assertEqual(
+            producer.name, "apply_async/tests.test_tasks.hidden_task"
+        )
+        self.assertEqual(producer.kind, SpanKind.PRODUCER)
+
+        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)

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

@@ -185,6 +185,13 @@ def fn_task():
         utils.detach_span(fn_task, task_id)
         self.assertEqual(utils.retrieve_span(fn_task, task_id), (None, None))
 
+    def test_optional_task_span_attach(self):
+        task_id = "7c6731af-9533-40c3-83a9-25b58f0d837f"
+        span = trace._Span("name", mock.Mock(spec=trace_api.SpanContext))
+
+        # assert this is is a no-aop
+        self.assertIsNone(utils.attach_span(None, task_id, span))
+
     def test_span_delete_empty(self):
         # ensure detach_span doesn't raise an exception if span is not present
         @self.app.task