Zipkin: Fix OTLP events to Zipkin annotations translation

Author: owais

exporter/opentelemetry-exporter-zipkin/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Zipkin exporter now accepts a ``max_tag_value_length`` attribute to customize the
   maximum allowed size a tag value can have. ([#1151](https://github.com/open-telemetry/opentelemetry-python/pull/1151)) 
+- Fixed OTLP events to Zipkin annotations translation. ([#1161](https://github.com/open-telemetry/opentelemetry-python/pull/1161))
 
 ## Version 0.13b0
 

exporter/opentelemetry-exporter-zipkin/src/opentelemetry/exporter/zipkin/__init__.py

@@ -237,20 +237,25 @@ def _extract_tags_from_span(self, span: Span):
             tags.update(self._extract_tags_from_dict(span.resource.attributes))
         return tags
 
-    def _extract_annotations_from_events(
-        self, events
-    ):  # pylint: disable=R0201
-        return (
-            [
+    def _extract_annotations_from_events(self, events):
+        if not events:
+            return None
+
+        annotations = []
+        for event in events:
+            attrs = {}
+            for key, value in event.attributes.items():
+                if isinstance(value, str):
+                    value = value[: self.max_tag_value_length]
+                attrs[key] = value
+
+            annotations.append(
                 {
-                    "timestamp": _nsec_to_usec_round(e.timestamp),
-                    "value": e.name,
+                    "timestamp": _nsec_to_usec_round(event.timestamp),
+                    "value": json.dumps({event.name: attrs}),
                 }
-                for e in events
-            ]
-            if events
-            else None
-        )
+            )
+        return annotations
 
 
 def _nsec_to_usec_round(nsec):

exporter/opentelemetry-exporter-zipkin/tests/test_zipkin_exporter.py

@@ -223,7 +223,15 @@ def test_export(self):
                 "annotations": [
                     {
                         "timestamp": event_timestamp // 10 ** 3,
-                        "value": "event0",
+                        "value": json.dumps(
+                            {
+                                "event0": {
+                                    "annotation_bool": True,
+                                    "annotation_string": "annotation_test",
+                                    "key_float": 0.3,
+                                }
+                            }
+                        ),
                     }
                 ],
                 "debug": True,