docs: add example to show how to drop measurements from an instrument (#2826)

Author: srikanthccv

docs/examples/views/README.rst

@@ -6,6 +6,7 @@ These examples show how to customize the metrics that are output by the SDK usin
 * change_aggregation: Shows how to configure to change the default aggregation for an instrument.
 * change_name: Shows how to change the name of a metric.
 * limit_num_of_attrs: Shows how to limit the number of attributes that are output for a metric.
+* drop_metrics_from_instrument: Shows how to drop measurements from an instrument.
 
 The source files of these examples are available :scm_web:`here <docs/examples/views/>`.
 

docs/examples/views/drop_metrics_from_instrument.py

@@ -0,0 +1,53 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import random
+import time
+
+from opentelemetry.metrics import get_meter_provider, set_meter_provider
+from opentelemetry.sdk.metrics import Counter, MeterProvider
+from opentelemetry.sdk.metrics.export import (
+    ConsoleMetricExporter,
+    PeriodicExportingMetricReader,
+)
+from opentelemetry.sdk.metrics.view import DropAggregation, View
+
+# Create a view matching the counter instrument `my.counter`
+# and configure the view to drop the aggregation.
+drop_aggregation_view = View(
+    instrument_type=Counter,
+    instrument_name="my.counter",
+    aggregation=DropAggregation(),
+)
+
+exporter = ConsoleMetricExporter()
+
+reader = PeriodicExportingMetricReader(exporter, export_interval_millis=1_000)
+provider = MeterProvider(
+    metric_readers=[
+        reader,
+    ],
+    views=[
+        drop_aggregation_view,
+    ],
+)
+set_meter_provider(provider)
+
+meter = get_meter_provider().get_meter("view-drop-aggregation", "0.1.2")
+
+my_counter = meter.create_counter("my.counter")
+
+while 1:
+    my_counter.add(random.randint(1, 10))
+    time.sleep(random.random())