fix(metrics): fix metric reader types and tests (open-telemetry#4938)

* chore(metrics): fix metric reader types and tests

* Fix lint

* Fix lint

* Changelog

---------

Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>

Author: anuraaga

CHANGELOG.md

@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- `opentelemetry-sdk`: fix type annotations on `MetricReader` and related types
+  ([#4938](https://github.com/open-telemetry/opentelemetry-python/pull/4938/))
+
 ## Version 1.40.0/0.61b0 (2026-03-04)
 
 - `opentelemetry-sdk`: deprecate `LoggingHandler` in favor of `opentelemetry-instrumentation-logging`, see `opentelemetry-instrumentation-logging` documentation

opentelemetry-sdk/src/opentelemetry/sdk/_logs/_internal/export/__init__.py

@@ -134,9 +134,9 @@ class ConsoleLogRecordExporter(LogRecordExporter):
     def __init__(
         self,
         out: IO = sys.stdout,
-        formatter: Callable[
-            [ReadableLogRecord], str
-        ] = lambda record: record.to_json() + linesep,
+        formatter: Callable[[ReadableLogRecord], str] = lambda record: (
+            record.to_json() + linesep
+        ),
     ):
         self.out = out
         self.formatter = formatter

opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/export/__init__.py

@@ -144,9 +144,9 @@ class ConsoleMetricExporter(MetricExporter):
     def __init__(
         self,
         out: IO = stdout,
-        formatter: Callable[
-            [MetricsData], str
-        ] = lambda metrics_data: metrics_data.to_json() + linesep,
+        formatter: Callable[[MetricsData], str] = lambda metrics_data: (
+            metrics_data.to_json() + linesep
+        ),
         preferred_temporality: dict[type, AggregationTemporality]
         | None = None,
         preferred_aggregation: dict[
@@ -353,7 +353,7 @@ def _set_collect_callback(
                 "opentelemetry.sdk.metrics.export.MetricReader",
                 AggregationTemporality,
             ],
-            Iterable["opentelemetry.sdk.metrics.export.Metric"],
+            MetricsData,
         ],
     ) -> None:
         """This function is internal to the SDK. It should not be called or overridden by users"""

opentelemetry-sdk/src/opentelemetry/sdk/metrics/_internal/measurement_consumer.py

@@ -17,7 +17,7 @@
 from abc import ABC, abstractmethod
 from threading import Lock
 from time import time_ns
-from typing import Iterable, List, Mapping, Optional
+from typing import List, Mapping, Optional
 
 # This kind of import is needed to avoid Sphinx errors.
 import opentelemetry.sdk.metrics
@@ -29,7 +29,7 @@
 from opentelemetry.sdk.metrics._internal.metric_reader_storage import (
     MetricReaderStorage,
 )
-from opentelemetry.sdk.metrics._internal.point import Metric
+from opentelemetry.sdk.metrics._internal.point import MetricsData
 
 
 class MeasurementConsumer(ABC):
@@ -51,7 +51,7 @@ def collect(
         self,
         metric_reader: "opentelemetry.sdk.metrics.MetricReader",
         timeout_millis: float = 10_000,
-    ) -> Optional[Iterable[Metric]]:
+    ) -> Optional[MetricsData]:
         pass
 
 
@@ -104,7 +104,7 @@ def collect(
         self,
         metric_reader: "opentelemetry.sdk.metrics.MetricReader",
         timeout_millis: float = 10_000,
-    ) -> Optional[Iterable[Metric]]:
+    ) -> Optional[MetricsData]:
         with self._lock:
             metric_reader_storage = self._reader_storages[metric_reader]
             # for now, just use the defaults

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

@@ -300,9 +300,9 @@ def __init__(
         self,
         service_name: str | None = None,
         out: typing.IO = sys.stdout,
-        formatter: typing.Callable[
-            [ReadableSpan], str
-        ] = lambda span: span.to_json() + linesep,
+        formatter: typing.Callable[[ReadableSpan], str] = lambda span: (
+            span.to_json() + linesep
+        ),
     ):
         self.out = out
         self.formatter = formatter

opentelemetry-sdk/tests/metrics/test_in_memory_metric_reader.py

@@ -20,21 +20,32 @@
 
 from opentelemetry.metrics import Observation
 from opentelemetry.sdk.metrics import Counter, MeterProvider
+from opentelemetry.sdk.metrics._internal.point import (
+    MetricsData,
+    ResourceMetrics,
+    ScopeMetrics,
+)
 from opentelemetry.sdk.metrics.export import (
     AggregationTemporality,
     InMemoryMetricReader,
     Metric,
     NumberDataPoint,
     Sum,
 )
+from opentelemetry.sdk.resources import Resource
+from opentelemetry.sdk.util.instrumentation import InstrumentationScope
 
 
 class TestInMemoryMetricReader(TestCase):
     def test_no_metrics(self):
-        mock_collect_callback = Mock(return_value=[])
+        mock_collect_callback = Mock(
+            return_value=MetricsData(resource_metrics=[])
+        )
         reader = InMemoryMetricReader()
         reader._set_collect_callback(mock_collect_callback)
-        self.assertEqual(reader.get_metrics_data(), [])
+        self.assertEqual(
+            reader.get_metrics_data(), MetricsData(resource_metrics=[])
+        )
         mock_collect_callback.assert_called_once()
 
     def test_converts_metrics_to_list(self):
@@ -55,15 +66,32 @@ def test_converts_metrics_to_list(self):
                 is_monotonic=True,
             ),
         )
-        mock_collect_callback = Mock(return_value=(metric,))
+        metric_data = MetricsData(
+            resource_metrics=[
+                ResourceMetrics(
+                    scope_metrics=[
+                        ScopeMetrics(
+                            metrics=[metric],
+                            scope=InstrumentationScope(name="test"),
+                            schema_url="",
+                        )
+                    ],
+                    resource=Resource.create(),
+                    schema_url="",
+                )
+            ]
+        )
+        mock_collect_callback = Mock(return_value=metric_data)
         reader = InMemoryMetricReader()
         reader._set_collect_callback(mock_collect_callback)
 
         returned_metrics = reader.get_metrics_data()
         mock_collect_callback.assert_called_once()
-        self.assertIsInstance(returned_metrics, tuple)
-        self.assertEqual(len(returned_metrics), 1)
-        self.assertIs(returned_metrics[0], metric)
+        self.assertIsNotNone(returned_metrics)
+        self.assertIs(
+            returned_metrics.resource_metrics[0].scope_metrics[0].metrics[0],
+            metric,
+        )
 
     def test_shutdown(self):
         # shutdown should always be successful

opentelemetry-sdk/tests/metrics/test_periodic_exporting_metric_reader.py

@@ -19,13 +19,18 @@
 import weakref
 from logging import WARNING
 from time import sleep, time_ns
-from typing import Optional, Sequence
+from typing import Optional
 from unittest.mock import Mock
 
 import pytest
 
 from opentelemetry.sdk.metrics import Counter, MetricsTimeoutError
 from opentelemetry.sdk.metrics._internal import _Counter
+from opentelemetry.sdk.metrics._internal.point import (
+    MetricsData,
+    ResourceMetrics,
+    ScopeMetrics,
+)
 from opentelemetry.sdk.metrics.export import (
     AggregationTemporality,
     Gauge,
@@ -40,6 +45,8 @@
     DefaultAggregation,
     LastValueAggregation,
 )
+from opentelemetry.sdk.resources import Resource
+from opentelemetry.sdk.util.instrumentation import InstrumentationScope
 from opentelemetry.test.concurrency_test import ConcurrencyTestBase
 
 
@@ -48,7 +55,7 @@ def __init__(
         self, wait=0, preferred_temporality=None, preferred_aggregation=None
     ):
         self.wait = wait
-        self.metrics = []
+        self.metrics: list[MetricsData] = []
         self._shutdown = False
         super().__init__(
             preferred_temporality=preferred_temporality,
@@ -57,13 +64,13 @@ def __init__(
 
     def export(
         self,
-        metrics_data: Sequence[Metric],
+        metrics_data: MetricsData,
         timeout_millis: float = 10_000,
         **kwargs,
     ) -> MetricExportResult:
         sleep(self.wait)
-        self.metrics.extend(metrics_data)
-        return True
+        self.metrics.append(metrics_data)
+        return MetricExportResult.SUCCESS
 
     def shutdown(self, timeout_millis: float = 30_000, **kwargs) -> None:
         self._shutdown = True
@@ -126,6 +133,21 @@ def collect(self, timeout_millis: float = 10_000) -> None:
         ),
     ),
 ]
+metrics = MetricsData(
+    resource_metrics=[
+        ResourceMetrics(
+            scope_metrics=[
+                ScopeMetrics(
+                    metrics=metrics_list,
+                    scope=InstrumentationScope(name="test"),
+                    schema_url="",
+                )
+            ],
+            resource=Resource.create(),
+            schema_url="",
+        )
+    ]
+)
 
 
 class TestPeriodicExportingMetricReader(ConcurrencyTestBase):
@@ -137,7 +159,12 @@ def test_defaults(self):
             pmr.shutdown()
 
     def _create_periodic_reader(
-        self, metrics, exporter, collect_wait=0, interval=60000, timeout=30000
+        self,
+        metrics_data: MetricsData,
+        exporter,
+        collect_wait=0,
+        interval=60000,
+        timeout=30000,
     ):
         pmr = PeriodicExportingMetricReader(
             exporter,
@@ -147,7 +174,7 @@ def _create_periodic_reader(
 
         def _collect(reader, timeout_millis):
             sleep(collect_wait)
-            pmr._receive_metrics(metrics, timeout_millis)
+            return metrics_data
 
         pmr._set_collect_callback(_collect)
         return pmr
@@ -198,24 +225,26 @@ def test_ticker_value_exception_on_negative(self):
     def test_ticker_collects_metrics(self):
         exporter = FakeMetricsExporter()
 
-        pmr = self._create_periodic_reader(
-            metrics_list, exporter, interval=100
-        )
+        pmr = self._create_periodic_reader(metrics, exporter, interval=100)
         sleep(0.15)
-        self.assertEqual(exporter.metrics, metrics_list)
+        self.assertEqual(exporter.metrics[0], metrics)
         pmr.shutdown()
 
     def test_shutdown(self):
         exporter = FakeMetricsExporter()
 
-        pmr = self._create_periodic_reader([], exporter)
+        pmr = self._create_periodic_reader(
+            MetricsData(resource_metrics=[]), exporter
+        )
         pmr.shutdown()
-        self.assertEqual(exporter.metrics, [])
+        self.assertEqual(exporter.metrics[0], MetricsData(resource_metrics=[]))
         self.assertTrue(pmr._shutdown)
         self.assertTrue(exporter._shutdown)
 
     def test_shutdown_multiple_times(self):
-        pmr = self._create_periodic_reader([], FakeMetricsExporter())
+        pmr = self._create_periodic_reader(
+            MetricsData(resource_metrics=[]), FakeMetricsExporter()
+        )
         with self.assertLogs(level="WARNING") as w:
             self.run_with_many_threads(pmr.shutdown)
         self.assertTrue("Can't shutdown multiple times" in w.output[0])