Add runtime validation in setAttribute (open-telemetry#348)

Validate attribute value data types before adding to span
Add lists as an accepted data type.

By adding validation during the setAttribute phase, this
allows allows exporters to avoid redundant code to validate
attributes.

opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py

@@ -18,6 +18,7 @@
 import random
 import threading
 from contextlib import contextmanager
+from numbers import Number
 from types import TracebackType
 from typing import Iterator, Optional, Sequence, Tuple, Type
 
@@ -216,8 +217,39 @@ def set_attribute(self, key: str, value: types.AttributeValue) -> None:
         if has_ended:
             logger.warning("Setting attribute on ended span.")
             return
+
+        if isinstance(value, Sequence):
+            error_message = self._check_attribute_value_sequence(value)
+            if error_message is not None:
+                logger.warning("%s in attribute value sequence", error_message)
+                return
+        elif not isinstance(value, (bool, str, Number, Sequence)):
+            logger.warning("invalid type for attribute value")
+            return
+
         self.attributes[key] = value
 
+    @staticmethod
+    def _check_attribute_value_sequence(sequence: Sequence) -> Optional[str]:
+        """
+        Checks if sequence items are valid and are of the same type
+        """
+        if len(sequence) == 0:
+            return None
+
+        first_element_type = type(sequence[0])
+
+        if issubclass(first_element_type, Number):
+            first_element_type = Number
+
+        if first_element_type not in (bool, str, Number):
+            return "invalid type"
+
+        for element in sequence:
+            if not isinstance(element, first_element_type):
+                return "different type"
+        return None
+
     def add_event(
         self,
         name: str,

opentelemetry-sdk/tests/trace/test_trace.py

@@ -368,7 +368,11 @@ def test_attributes(self):
             root.set_attribute("attr-key", "attr-value1")
             root.set_attribute("attr-key", "attr-value2")
 
-            self.assertEqual(len(root.attributes), 7)
+            root.set_attribute("empty-list", [])
+            root.set_attribute("list-of-bools", [True, True, False])
+            root.set_attribute("list-of-numerics", [123, 3.14, 0])
+
+            self.assertEqual(len(root.attributes), 10)
             self.assertEqual(root.attributes["component"], "http")
             self.assertEqual(root.attributes["http.method"], "GET")
             self.assertEqual(
@@ -379,6 +383,13 @@ def test_attributes(self):
             self.assertEqual(root.attributes["http.status_text"], "OK")
             self.assertEqual(root.attributes["misc.pi"], 3.14)
             self.assertEqual(root.attributes["attr-key"], "attr-value2")
+            self.assertEqual(root.attributes["empty-list"], [])
+            self.assertEqual(
+                root.attributes["list-of-bools"], [True, True, False]
+            )
+            self.assertEqual(
+                root.attributes["list-of-numerics"], [123, 3.14, 0]
+            )
 
         attributes = {
             "attr-key": "val",
@@ -393,6 +404,46 @@ def test_attributes(self):
             self.assertEqual(root.attributes["attr-key2"], "val2")
             self.assertEqual(root.attributes["attr-in-both"], "span-attr")
 
+    def test_invalid_attribute_values(self):
+        with self.tracer.start_as_current_span("root") as root:
+            root.set_attribute("non-primitive-data-type", dict())
+            root.set_attribute(
+                "list-of-mixed-data-types-numeric-first",
+                [123, False, "string"],
+            )
+            root.set_attribute(
+                "list-of-mixed-data-types-non-numeric-first",
+                [False, 123, "string"],
+            )
+            root.set_attribute(
+                "list-with-non-primitive-data-type", [dict(), 123]
+            )
+
+            self.assertEqual(len(root.attributes), 0)
+
+    def test_check_sequence_helper(self):
+        # pylint: disable=protected-access
+        self.assertEqual(
+            trace.Span._check_attribute_value_sequence([1, 2, 3.4, "ss", 4]),
+            "different type",
+        )
+        self.assertEqual(
+            trace.Span._check_attribute_value_sequence([dict(), 1, 2, 3.4, 4]),
+            "invalid type",
+        )
+        self.assertEqual(
+            trace.Span._check_attribute_value_sequence(
+                ["sw", "lf", 3.4, "ss"]
+            ),
+            "different type",
+        )
+        self.assertIsNone(
+            trace.Span._check_attribute_value_sequence([1, 2, 3.4, 5])
+        )
+        self.assertIsNone(
+            trace.Span._check_attribute_value_sequence(["ss", "dw", "fw"])
+        )
+
     def test_sampling_attributes(self):
         decision_attributes = {
             "sampler-attr": "sample-val",