feat: add Autoscaling API

protos/google/bigtable/admin/v2/bigtable_instance_admin.proto

@@ -1,4 +1,4 @@
-// Copyright 2020 Google LLC
+// Copyright 2021 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -51,6 +51,12 @@ service BigtableInstanceAdmin {
       "https://www.googleapis.com/auth/cloud-platform.read-only";
 
   // Create an instance within a project.
+  //
+  // Note that exactly one of Cluster.serve_nodes and
+  // Cluster.cluster_config.cluster_autoscaling_config can be set. If
+  // serve_nodes is set to non-zero, then the cluster is manually scaled. If
+  // cluster_config.cluster_autoscaling_config is non-empty, then autoscaling is
+  // enabled.
   rpc CreateInstance(CreateInstanceRequest) returns (google.longrunning.Operation) {
     option (google.api.http) = {
       post: "/v2/{parent=projects/*}/instances"
@@ -112,6 +118,12 @@ service BigtableInstanceAdmin {
   }
 
   // Creates a cluster within an instance.
+  //
+  // Note that exactly one of Cluster.serve_nodes and
+  // Cluster.cluster_config.cluster_autoscaling_config can be set. If
+  // serve_nodes is set to non-zero, then the cluster is manually scaled. If
+  // cluster_config.cluster_autoscaling_config is non-empty, then autoscaling is
+  // enabled.
   rpc CreateCluster(CreateClusterRequest) returns (google.longrunning.Operation) {
     option (google.api.http) = {
       post: "/v2/{parent=projects/*/instances/*}/clusters"
@@ -141,6 +153,10 @@ service BigtableInstanceAdmin {
   }
 
   // Updates a cluster within an instance.
+  //
+  // Note that UpdateCluster does not support updating
+  // cluster_config.cluster_autoscaling_config. In order to update it, you
+  // must use PartialUpdateCluster.
   rpc UpdateCluster(Cluster) returns (google.longrunning.Operation) {
     option (google.api.http) = {
       put: "/v2/{name=projects/*/instances/*/clusters/*}"
@@ -152,6 +168,30 @@ service BigtableInstanceAdmin {
     };
   }
 
+  // Partially updates a cluster within a project. This method is the preferred
+  // way to update a Cluster.
+  //
+  // To enable and update autoscaling, set
+  // cluster_config.cluster_autoscaling_config. When autoscaling is enabled,
+  // serve_nodes is treated as an OUTPUT_ONLY field, meaning that updates to it
+  // are ignored. Note that an update cannot simultaneously set serve_nodes to
+  // non-zero and cluster_config.cluster_autoscaling_config to non-empty, and
+  // also specify both in the update_mask.
+  //
+  // To disable autoscaling, clear cluster_config.cluster_autoscaling_config,
+  // and explicitly set a serve_node count via the update_mask.
+  rpc PartialUpdateCluster(PartialUpdateClusterRequest) returns (google.longrunning.Operation) {
+    option (google.api.http) = {
+      patch: "/v2/{cluster.name=projects/*/instances/*/clusters/*}"
+      body: "cluster"
+    };
+    option (google.api.method_signature) = "cluster,update_mask";
+    option (google.longrunning.operation_info) = {
+      response_type: "Cluster"
+      metadata_type: "PartialUpdateClusterMetadata"
+    };
+  }
+
   // Deletes a cluster from an instance.
   rpc DeleteCluster(DeleteClusterRequest) returns (google.protobuf.Empty) {
     option (google.api.http) = {
@@ -457,6 +497,28 @@ message UpdateClusterMetadata {
   google.protobuf.Timestamp finish_time = 3;
 }
 
+// The metadata for the Operation returned by PartialUpdateCluster.
+message PartialUpdateClusterMetadata {
+  // The time at which the original request was received.
+  google.protobuf.Timestamp request_time = 1;
+
+  // The time at which the operation failed or was completed successfully.
+  google.protobuf.Timestamp finish_time = 2;
+
+  // The original request for PartialUpdateCluster.
+  PartialUpdateClusterRequest original_request = 3;
+}
+
+// Request message for BigtableInstanceAdmin.PartialUpdateCluster.
+message PartialUpdateClusterRequest {
+  // Required. The Cluster which contains the partial updates to be applied, subject to
+  // the update_mask.
+  Cluster cluster = 1 [(google.api.field_behavior) = REQUIRED];
+
+  // Required. The subset of Cluster fields which should be replaced.
+  google.protobuf.FieldMask update_mask = 2 [(google.api.field_behavior) = REQUIRED];
+}
+
 // Request message for BigtableInstanceAdmin.CreateAppProfile.
 message CreateAppProfileRequest {
   // Required. The unique name of the instance in which to create the new app profile.

protos/google/bigtable/admin/v2/common.proto

@@ -1,4 +1,4 @@
-// Copyright 2020 Google LLC
+// Copyright 2021 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@ syntax = "proto3";
 package google.bigtable.admin.v2;
 
 import "google/protobuf/timestamp.proto";
+import "google/api/annotations.proto";
 
 option csharp_namespace = "Google.Cloud.Bigtable.Admin.V2";
 option go_package = "google.golang.org/genproto/googleapis/bigtable/admin/v2;admin";

protos/google/bigtable/admin/v2/instance.proto

@@ -114,6 +114,23 @@ message Instance {
   google.protobuf.Timestamp create_time = 7 [(google.api.field_behavior) = OUTPUT_ONLY];
 }
 
+// The Autoscaling targets for a Cluster. These determine the recommended nodes.
+message AutoscalingTargets {
+  // The cpu utilization that the Autoscaler should be trying to achieve.
+  // This number is on a scale from 0 (no utilization) to
+  // 100 (total utilization).
+  int32 cpu_utilization_percent = 2;
+}
+
+// Limits for the number of nodes a Cluster can autoscale up/down to.
+message AutoscalingLimits {
+  // Required. Minimum number of nodes to scale down to.
+  int32 min_serve_nodes = 1 [(google.api.field_behavior) = REQUIRED];
+
+  // Required. Maximum number of nodes to scale up to.
+  int32 max_serve_nodes = 2 [(google.api.field_behavior) = REQUIRED];
+}
+
 // A resizable group of nodes in a particular cloud location, capable
 // of serving all [Tables][google.bigtable.admin.v2.Table] in the parent
 // [Instance][google.bigtable.admin.v2.Instance].
@@ -123,6 +140,21 @@ message Cluster {
     pattern: "projects/{project}/instances/{instance}/clusters/{cluster}"
   };
 
+  // Autoscaling config for a cluster.
+  message ClusterAutoscalingConfig {
+    // Required. Autoscaling limits for this cluster.
+    AutoscalingLimits autoscaling_limits = 1 [(google.api.field_behavior) = REQUIRED];
+
+    // Required. Autoscaling targets for this cluster.
+    AutoscalingTargets autoscaling_targets = 2 [(google.api.field_behavior) = REQUIRED];
+  }
+
+  // Configuration for a cluster.
+  message ClusterConfig {
+    // Autoscaling configuration for this cluster.
+    ClusterAutoscalingConfig cluster_autoscaling_config = 1;
+  }
+
   // Cloud Key Management Service (Cloud KMS) settings for a CMEK-protected
   // cluster.
   message EncryptionConfig {
@@ -180,9 +212,14 @@ message Cluster {
   // The current state of the cluster.
   State state = 3 [(google.api.field_behavior) = OUTPUT_ONLY];
 
-  // Required. The number of nodes allocated to this cluster. More nodes enable
-  // higher throughput and more consistent performance.
-  int32 serve_nodes = 4 [(google.api.field_behavior) = REQUIRED];
+  // The number of nodes allocated to this cluster. More nodes enable higher
+  // throughput and more consistent performance.
+  int32 serve_nodes = 4;
+
+  oneof config {
+    // Configuration for this cluster.
+    ClusterConfig cluster_config = 7;
+  }
 
   // (`CreationOnly`)
   // The type of storage used by this cluster to serve its