From 9aeb45a90e98f5cbc58aef36780931efc750459a Mon Sep 17 00:00:00 2001
From: Alex Boten <aboten@lightstep.com>
Date: Mon, 20 Dec 2021 08:54:41 -0800
Subject: [PATCH] add more stubs in place

---
 .../proto/grpc/_metric_exporter/__init__.py   | 15 ++++++++
 .../sdk/_metrics/export/metric_exporter.py    | 38 ++++++++++++++++++-
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/_metric_exporter/__init__.py b/exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/_metric_exporter/__init__.py
index 92bb52c37e8..87227e73917 100644
--- a/exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/_metric_exporter/__init__.py
+++ b/exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/_metric_exporter/__init__.py
@@ -16,6 +16,9 @@
 from opentelemetry.exporter.otlp.proto.grpc.exporter import (
     OTLPExporterMixin,
 )
+from opentelemetry.proto.collector.metrics.v1.metrics_service_pb2_grpc import (
+    MetricsServiceStub,
+)
 from opentelemetry.sdk._metrics import (
     MetricData,
 )
@@ -30,6 +33,9 @@ class OTLPMetricExporter(
     MetricExporter,
     OTLPExporterMixin,
 ):
+    _result = MetricExportResult
+    _stub = MetricsServiceStub
+
     def __init__(
         self,
         endpoint: Optional[str] = None,
@@ -54,3 +60,12 @@ def _translate_data(
         self, data: Sequence[MetricData]
     ) -> MetricExportResult:
         return super()._translate_data(data)
+
+    def export(self, batch: Sequence[MetricData]) -> MetricExportResult:
+        for data in batch:
+            # TODO: do something with the data
+            pass
+        return MetricExportResult.SUCCESS
+
+    def shutdown(self):
+        pass
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/_metrics/export/metric_exporter.py b/opentelemetry-sdk/src/opentelemetry/sdk/_metrics/export/metric_exporter.py
index 5365a2899eb..5db4d836d78 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/_metrics/export/metric_exporter.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/_metrics/export/metric_exporter.py
@@ -13,7 +13,13 @@
 # limitations under the License.
 
 import abc
+import sys
 from enum import Enum
+from os import linesep
+from typing import IO, Callable, Sequence
+
+from opentelemetry.sdk._metrics import MetricData
+from opentelemetry.sdk._metrics.measurement import Measurement
 
 
 class MetricExportResult(Enum):
@@ -28,8 +34,18 @@ class MetricExporter(abc.ABC):
     in their own format.
     """
 
+    def export(self, metrics: Sequence[MetricData]) -> "MetricExportResult":
+        """Exports a batch of telemetry data.
+
+        Args:
+            metrics: The list of `opentelemetry.trace.Span` objects to be exported
+
+        Returns:
+            The result of the export
+        """
+
     @abc.abstractmethod
-    def shutdown(self):
+    def shutdown(self) -> None:
         """Shuts down the exporter.
 
         Called when the SDK is shut down.
@@ -43,3 +59,23 @@ class ConsoleMetricExporter(MetricExporter):
     This class can be used for diagnostic purposes. It prints the exported
     metrics to the console STDOUT.
     """
+
+    def __init__(
+        self,
+        out: IO = sys.stdout,
+        formatter: Callable[
+            [Measurement], str
+        ] = lambda record: record.to_json()
+        + linesep,
+    ):
+        self.out = out
+        self.formatter = formatter
+
+    def export(self, batch: Sequence[MetricData]) -> MetricExportResult:
+        for data in batch:
+            self.out.write(self.formatter(data.log_record))
+        self.out.flush()
+        return MetricExportResult.SUCCESS
+
+    def shutdown(self) -> None:
+        pass