Actually return last batch result like grpc

Author: tammy-baylis-swi

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/metric_exporter/__init__.py

@@ -290,16 +290,12 @@ def export(
         export_result = MetricExportResult.SUCCESS
 
         for split_metrics_data in split_metrics_batches:
-            batch_result = self._export_with_retries(
+            export_result = self._export_with_retries(
                 split_metrics_data.SerializeToString(),
                 deadline_sec,
             )
 
-            if batch_result == MetricExportResult.FAILURE:
-                # If any batch fails, return failure immediately
-                return MetricExportResult.FAILURE
-
-        # Return SUCCESS only if all batches succeeded
+        # Return export result of the last batch, like gRPC exporter
         return export_result
 
     def _split_metrics_data(

exporter/opentelemetry-exporter-otlp-proto-http/tests/metrics/test_otlp_metrics_exporter.py

@@ -918,6 +918,8 @@ def test_export_retries_with_batching_failure_first(
         mock_export.side_effect = [
             # Non-retryable
             MagicMock(ok=False, status_code=400, reason="bad request"),
+            MagicMock(ok=True),
+            MagicMock(ok=True),
         ]
         mock_encode_metrics.return_value = pb2.MetricsData(
             resource_metrics=[
@@ -965,8 +967,8 @@ def test_export_retries_with_batching_failure_first(
 
         exporter = OTLPMetricExporter(max_export_batch_size=2)
         result = exporter.export("foo")
-        self.assertEqual(result, MetricExportResult.FAILURE)
-        self.assertEqual(mock_export.call_count, 1)
+        self.assertEqual(result, MetricExportResult.SUCCESS)
+        self.assertEqual(mock_export.call_count, 2)
         mock_export.assert_has_calls(
             [
                 call(batch_1.SerializeToString(), 10),