fixing documentation and return value (#2399)

Author: Alex Boten

docs/examples/metrics/example.py

@@ -3,12 +3,14 @@
     OTLPMetricExporter,
 )
 from opentelemetry.sdk._metrics import MeterProvider
+from opentelemetry.sdk._metrics.export import PeriodicExportingMetricReader
 
-provider = MeterProvider()
 exporter = OTLPMetricExporter(insecure=True)
-# TODO: fill in details for metric reader
+reader = PeriodicExportingMetricReader(exporter)
+provider = MeterProvider(metric_readers=[reader])
 set_meter_provider(provider)
 
 meter = get_meter_provider().get_meter("getting-started")
 counter = meter.create_counter("first_counter")
+counter.add(1)
 # TODO: fill in details for additional metrics

docs/getting_started/metrics_example.py

@@ -17,13 +17,17 @@
 
 from opentelemetry._metrics import get_meter_provider, set_meter_provider
 from opentelemetry.sdk._metrics import MeterProvider
-from opentelemetry.sdk._metrics.export import ConsoleMetricExporter
+from opentelemetry.sdk._metrics.export import (
+    ConsoleMetricExporter,
+    PeriodicExportingMetricReader,
+)
 
-provider = MeterProvider()
 exporter = ConsoleMetricExporter()
-# TODO: fill in details for metric reader
+reader = PeriodicExportingMetricReader(exporter)
+provider = MeterProvider(metric_readers=[reader])
 set_meter_provider(provider)
 
 meter = get_meter_provider().get_meter("getting-started")
 counter = meter.create_counter("first_counter")
+counter.add(1)
 # TODO: fill in details for additional metrics

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

@@ -154,6 +154,8 @@ def _ticker(self) -> None:
         self.collect()
 
     def _receive_metrics(self, metrics: Iterable[Metric]) -> None:
+        if metrics is None:
+            return
         token = attach(set_value(_SUPPRESS_INSTRUMENTATION_KEY, True))
         try:
             self._exporter.export(metrics)
@@ -172,4 +174,5 @@ def _shutdown():
 
         self._shutdown_event.set()
         self._daemon_thread.join()
-        return self._exporter.shutdown()
+        self._exporter.shutdown()
+        return True