gcp-observability: add new *compressed_bytes_per_rpc views (#9893)

* Add new metric views; Register latency and bytes per metrics views for observability
* update view description to inlcude client/server
* Use pre-defined aggregation from OpenCensus for bytes histogram
* updated view names

census/src/main/java/io/grpc/census/internal/ObservabilityCensusConstants.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2023 The gRPC 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.
+ */
+
+package io.grpc.census.internal;
+
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_CLIENT_METHOD;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_CLIENT_RECEIVED_BYTES_PER_RPC;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_CLIENT_SENT_BYTES_PER_RPC;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_CLIENT_STATUS;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER_METHOD;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER_RECEIVED_BYTES_PER_RPC;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER_SENT_BYTES_PER_RPC;
+import static io.opencensus.contrib.grpc.metrics.RpcMeasureConstants.GRPC_SERVER_STATUS;
+
+import io.opencensus.contrib.grpc.metrics.RpcViewConstants;
+import io.opencensus.stats.Aggregation;
+import io.opencensus.stats.View;
+import java.util.Arrays;
+
+/** Temporary holder class for the observability specific OpenCensus constants.
+ *  The class will be removed once the new views are added in OpenCensus library. */
+public final class ObservabilityCensusConstants {
+
+  static final Aggregation AGGREGATION_WITH_BYTES_HISTOGRAM =
+      RpcViewConstants.GRPC_CLIENT_SENT_BYTES_PER_RPC_VIEW.getAggregation();
+
+  public static final View GRPC_CLIENT_SENT_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW =
+      View.create(
+          View.Name.create("grpc.io/client/sent_compressed_message_bytes_per_rpc"),
+          "Compressed message bytes sent per client RPC attempt",
+          GRPC_CLIENT_SENT_BYTES_PER_RPC,
+          AGGREGATION_WITH_BYTES_HISTOGRAM,
+          Arrays.asList(GRPC_CLIENT_METHOD, GRPC_CLIENT_STATUS));
+
+  public static final View GRPC_CLIENT_RECEIVED_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW =
+      View.create(
+          View.Name.create("grpc.io/client/received_compressed_message_bytes_per_rpc"),
+          "Compressed message bytes received per client RPC attempt",
+          GRPC_CLIENT_RECEIVED_BYTES_PER_RPC,
+          AGGREGATION_WITH_BYTES_HISTOGRAM,
+          Arrays.asList(GRPC_CLIENT_METHOD, GRPC_CLIENT_STATUS));
+
+  public static final View GRPC_SERVER_SENT_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW =
+      View.create(
+          View.Name.create("grpc.io/server/sent_compressed_message_bytes_per_rpc"),
+          "Compressed message bytes sent per server RPC",
+          GRPC_SERVER_SENT_BYTES_PER_RPC,
+          AGGREGATION_WITH_BYTES_HISTOGRAM,
+          Arrays.asList(GRPC_SERVER_METHOD, GRPC_SERVER_STATUS));
+
+  public static final View GRPC_SERVER_RECEIVED_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW =
+      View.create(
+          View.Name.create("grpc.io/server/received_compressed_message_bytes_per_rpc"),
+          "Compressed message bytes received per server RPC",
+          GRPC_SERVER_RECEIVED_BYTES_PER_RPC,
+          AGGREGATION_WITH_BYTES_HISTOGRAM,
+          Arrays.asList(GRPC_SERVER_METHOD, GRPC_SERVER_STATUS));
+
+  private ObservabilityCensusConstants() {}
+}

gcp-observability/src/main/java/io/grpc/gcp/observability/GcpObservability.java

@@ -28,6 +28,7 @@ import io.grpc.ServerInterceptor;
 import io.grpc.ServerStreamTracer;
 import io.grpc.census.InternalCensusStatsAccessor;
 import io.grpc.census.InternalCensusTracingAccessor;
+import io.grpc.census.internal.ObservabilityCensusConstants;
 import io.grpc.gcp.observability.interceptors.ConditionalClientInterceptor;
 import io.grpc.gcp.observability.interceptors.ConfigFilterHelper;
 import io.grpc.gcp.observability.interceptors.InternalLoggingChannelInterceptor;
@@ -152,10 +153,20 @@ public final class GcpObservability implements AutoCloseable {
     // client views
     viewManager.registerView(RpcViewConstants.GRPC_CLIENT_COMPLETED_RPC_VIEW);
     viewManager.registerView(RpcViewConstants.GRPC_CLIENT_STARTED_RPC_VIEW);
+    viewManager.registerView(RpcViewConstants.GRPC_CLIENT_ROUNDTRIP_LATENCY_VIEW);
+    viewManager.registerView(
+        ObservabilityCensusConstants.GRPC_CLIENT_SENT_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW);
+    viewManager.registerView(
+        ObservabilityCensusConstants.GRPC_CLIENT_RECEIVED_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW);
 
     // server views
     viewManager.registerView(RpcViewConstants.GRPC_SERVER_COMPLETED_RPC_VIEW);
     viewManager.registerView(RpcViewConstants.GRPC_SERVER_STARTED_RPC_VIEW);
+    viewManager.registerView(RpcViewConstants.GRPC_SERVER_SERVER_LATENCY_VIEW);
+    viewManager.registerView(
+        ObservabilityCensusConstants.GRPC_SERVER_SENT_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW);
+    viewManager.registerView(
+        ObservabilityCensusConstants.GRPC_SERVER_RECEIVED_COMPRESSED_MESSAGE_BYTES_PER_RPC_VIEW);
   }
 
   @VisibleForTesting