opentelemetry-exporter-otlp-proto-http: fix metric self-observability over-count on batch split

.changelog/5370.fixed

@@ -0,0 +1 @@
+`opentelemetry-exporter-otlp-proto-http`: fix the OTLP HTTP metric exporter self-observability metrics over-counting data points when `max_export_batch_size` splits a batch; each split now reports its own data-point count instead of the whole-batch count.

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

@@ -343,19 +343,15 @@ def export(
             _logger.warning("Exporter already shutdown, ignoring batch")
             return MetricExportResult.FAILURE
 
-        num_items = 0
-        for resource_metrics in metrics_data.resource_metrics:
-            for scope_metrics in resource_metrics.scope_metrics:
-                for metric in scope_metrics.metrics:
-                    num_items += len(metric.data.data_points)
-
         export_request = encode_metrics(metrics_data)
         deadline_sec = time() + self._timeout
 
         # If no batch size configured, export as single batch with retries as configured
         if self._max_export_batch_size is None:
             return self._export_with_retries(
-                export_request, deadline_sec, num_items
+                export_request,
+                deadline_sec,
+                _count_data_points(export_request),
             )
 
         # Else, export in batches of configured size
@@ -367,7 +363,7 @@ def export(
             export_result = self._export_with_retries(
                 split_metrics_data,
                 deadline_sec,
-                num_items,
+                _count_data_points(split_metrics_data),
             )
             if export_result != MetricExportResult.SUCCESS:
                 return MetricExportResult.FAILURE
@@ -404,6 +400,18 @@ def set_meter_provider(self, meter_provider: MeterProvider) -> None:
         )
 
 
+def _count_data_points(export_request: ExportMetricsServiceRequest) -> int:
+    """Count the number of data points in an encoded metrics export request."""
+    count = 0
+    for resource_metrics in export_request.resource_metrics:
+        for scope_metrics in resource_metrics.scope_metrics:
+            for metric in scope_metrics.metrics:
+                field_name = metric.WhichOneof("data")
+                if field_name:
+                    count += len(getattr(metric, field_name).data_points)
+    return count
+
+
 def _split_metrics_data(
     metrics_data: ExportMetricsServiceRequest,
     max_export_batch_size: int | None = None,

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

@@ -128,6 +128,56 @@ def setUp(self):
             ),
         }
 
+    @patch.dict(
+        "os.environ", {OTEL_PYTHON_SDK_INTERNAL_METRICS_ENABLED: "true"}
+    )
+    @patch.object(Session, "post")
+    def test_split_export_records_per_split_data_point_count(self, mock_post):
+        # When a batch is split, each split must record its own data-point
+        # count in the self-observability metric, not the whole-batch count.
+        resp = Response()
+        resp.status_code = 200
+        mock_post.return_value = resp
+        metrics_data = MetricsData(
+            resource_metrics=[
+                ResourceMetrics(
+                    resource=Resource(
+                        attributes={"a": 1}, schema_url="resource_schema_url"
+                    ),
+                    scope_metrics=[
+                        ScopeMetrics(
+                            scope=SDKInstrumentationScope(
+                                name="name", version="version"
+                            ),
+                            metrics=[
+                                _generate_sum("s1", 1),
+                                _generate_sum("s2", 2),
+                                _generate_sum("s3", 3),
+                            ],
+                            schema_url="scope_schema_url",
+                        )
+                    ],
+                    schema_url="resource_schema_url",
+                )
+            ]
+        )
+        exporter = OTLPMetricExporter(
+            max_export_batch_size=1, meter_provider=self.meter_provider
+        )
+        self.assertEqual(
+            exporter.export(metrics_data), MetricExportResult.SUCCESS
+        )
+        self.assertEqual(mock_post.call_count, 3)
+        internal = self.metric_reader.get_metrics_data()
+        scope_metrics = internal.resource_metrics[0].scope_metrics[0]
+        exported = next(
+            metric
+            for metric in scope_metrics.metrics
+            if metric.name == "otel.sdk.exporter.metric_data_point.exported"
+        )
+        total = sum(dp.value for dp in exported.data.data_points)
+        self.assertEqual(total, 3)
+
     def test_constructor_default(self):
         exporter = OTLPMetricExporter()