Simplified trace to_json to include empty and null values.

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

@@ -492,7 +492,7 @@ def to_json(self, indent=4):
         f_span["attributes"] = self._format_attributes(self._attributes)
         f_span["events"] = self._format_events(self._events)
         f_span["links"] = self._format_links(self._links)
-        f_span["resource"] = self._format_resource(self._resource)
+        f_span["resource"] = json.loads(self.resource.to_json())
 
         return json.dumps(f_span, indent=indent)
 
@@ -533,11 +533,6 @@ def _format_links(links):
             f_links.append(f_link)
         return f_links
 
-    @staticmethod
-    def _format_resource(resource):
-        resource_json_obj = json.loads(resource.to_json())
-        return {k: v for k, v in resource_json_obj.items() if v}
-
 
 class SpanLimits:
     """The limits that should be enforce on recorded data such as events, links, attributes etc.

opentelemetry-sdk/tests/trace/test_trace.py

@@ -1354,12 +1354,15 @@ def test_to_json(self):
     "attributes": {},
     "events": [],
     "links": [],
-    "resource": {}
+    "resource": {
+        "attributes": {},
+        "schema_url": ""
+    }
 }""",
         )
         self.assertEqual(
             span.to_json(indent=None),
-            '{"name": "span-name", "context": {"trace_id": "0x000000000000000000000000deadbeef", "span_id": "0x00000000deadbef0", "trace_state": "[]"}, "kind": "SpanKind.INTERNAL", "parent_id": "0x00000000deadbef0", "start_time": null, "end_time": null, "status": {"status_code": "UNSET"}, "attributes": {}, "events": [], "links": [], "resource": {}}',
+            '{"name": "span-name", "context": {"trace_id": "0x000000000000000000000000deadbeef", "span_id": "0x00000000deadbef0", "trace_state": "[]"}, "kind": "SpanKind.INTERNAL", "parent_id": "0x00000000deadbef0", "start_time": null, "end_time": null, "status": {"status_code": "UNSET"}, "attributes": {}, "events": [], "links": [], "resource": {"attributes": {}, "schema_url": ""}}',
         )
 
     def test_attributes_to_json(self):
@@ -1377,7 +1380,7 @@ def test_attributes_to_json(self):
             span.to_json(indent=None),
             '{"name": "span-name", "context": {"trace_id": "0x000000000000000000000000deadbeef", "span_id": "0x00000000deadbef0", "trace_state": "[]"}, "kind": "SpanKind.INTERNAL", "parent_id": null, "start_time": null, "end_time": null, "status": {"status_code": "UNSET"}, "attributes": {"key": "value"}, "events": [{"name": "event", "timestamp": "'
             + date_str
-            + '", "attributes": {"key2": "value2"}}], "links": [], "resource": {}}',
+            + '", "attributes": {"key2": "value2"}}], "links": [], "resource": {"attributes": {}, "schema_url": ""}}',
         )