Expose GKE desired_emulated_version update trigger in Cluster resource

mmv1/third_party/terraform/services/container/resource_container_cluster.go.tmpl

@@ -1205,6 +1205,21 @@ func ResourceContainerCluster() *schema.Resource {
 				Description:  `The logging service that the cluster should write logs to. Available options include logging.googleapis.com(Legacy Stackdriver), logging.googleapis.com/kubernetes(Stackdriver Kubernetes Engine Logging), and none. Defaults to logging.googleapis.com/kubernetes.`,
 			},
 
+{{- if ne $.TargetVersionName "ga" }}
+			"desired_emulated_version": {
+				Type:         schema.TypeString,
+				Optional:     true,
+				ValidateFunc: validation.StringMatch(regexp.MustCompile(`^[0-9]+\.[0-9]+$`), "desired_emulated_version must be in major.minor format"),
+				Description:  "The desired emulated version for the cluster. Set this to complete a rollback-safe upgrade.",
+			},
+
+			"emulated_version": {
+				Type:        schema.TypeString,
+				Computed:    true,
+				Description: `The current emulated Kubernetes version running on the GKE cluster control plane.`,
+			},
+{{- end }}
+
 			"maintenance_policy": {
 				Type:        schema.TypeList,
 				Optional:    true,
@@ -3584,6 +3599,11 @@ func resourceContainerClusterRead(d *schema.ResourceData, meta interface{}) erro
 	if err := d.Set("master_version", cluster.CurrentMasterVersion); err != nil {
 		return fmt.Errorf("Error setting master_version: %s", err)
 	}
+{{- if ne $.TargetVersionName "ga" }}
+	if err := d.Set("emulated_version", cluster.CurrentEmulatedVersion); err != nil {
+		return fmt.Errorf("Error setting emulated_version: %s", err)
+	}
+{{- end }}
 	if err := d.Set("node_version", cluster.CurrentNodeVersion); err != nil {
 		return fmt.Errorf("Error setting node_version: %s", err)
 	}
@@ -4546,6 +4566,24 @@ func resourceContainerClusterUpdate(d *schema.ResourceData, meta interface{}) er
 		log.Printf("[INFO] GKE cluster %s legacy ABAC has been updated to %v", d.Id(), enabled)
 	}
 
+{{- if ne $.TargetVersionName "ga" }}
+	if d.HasChange("desired_emulated_version") {
+		emulatedVersion := d.Get("desired_emulated_version").(string)
+		req := &container.UpdateClusterRequest{
+			Update: &container.ClusterUpdate{
+				DesiredEmulatedVersion: emulatedVersion,
+			},
+		}
+
+		updateF := updateFunc(req, "updating GKE master emulated version")
+		// Call update serially.
+		if err := transport_tpg.LockedCall(lockKey, updateF); err != nil {
+			return err
+		}
+		log.Printf("[INFO] GKE cluster %s: master emulated version has been updated to %s", d.Id(), emulatedVersion)
+	}
+{{- end }}
+
 	if d.HasChange("monitoring_service") || d.HasChange("logging_service") {
 		logging := d.Get("logging_service").(string)
 		monitoring := d.Get("monitoring_service").(string)

mmv1/third_party/terraform/services/container/resource_container_cluster_test.go.tmpl

@@ -18210,3 +18210,153 @@ func testAccContainerCluster_custom_subnet(clusterName string, networkName strin
 
 	`, clusterName, networkName, sri[0].SubnetName, additionalIpRangesStr, firstSubnet, firstSubnet)	
 }
+
+func TestAccContainerCluster_desiredEmulatedVersion(t *testing.T) {
+	t.Parallel()
+	clusterName := fmt.Sprintf("tf-test-cluster-%s", acctest.RandString(t, 10))
+	networkName := tpgcompute.BootstrapSharedTestNetwork(t, "gke-cluster")
+	subnetworkName := tpgcompute.BootstrapSubnet(t, "gke-cluster", networkName)
+
+	// We utilize standard, valid GKE staging versions for E2E minor upgrade transitions
+	fromVersion := "1.34.8-gke.1211000"
+	targetVersion := "1.35.5-gke.1117000"
+
+	acctest.VcrTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.AccTestPreCheck(t) },
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories(t),
+		CheckDestroy:             testAccCheckContainerClusterDestroyProducer(t),
+		Steps: []resource.TestStep{
+			// Step 1 (Create): Spin up a standard cluster at version 1.30 (Baseline)
+			{
+				Config: testAccContainerCluster_desiredEmulatedVersionBase(clusterName, networkName, subnetworkName, fromVersion),
+			},
+			{
+				ResourceName:            "google_container_cluster.primary",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"min_master_version", "deletion_protection"},
+			},
+			// Step 2 (Soak Upgrade): Upgrade master to target version 1.31 and activate 25-hour soak
+			{
+				Config: testAccContainerCluster_desiredEmulatedVersionSoak(clusterName, networkName, subnetworkName, fromVersion, targetVersion),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("google_container_cluster.primary", "min_master_version", targetVersion),
+				),
+			},
+			{
+				ResourceName:            "google_container_cluster.primary",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"min_master_version", "deletion_protection"},
+			},
+			// Step 3 (Declarative Complete): Set desired_emulated_version to 1.35 to complete the upgrade while soaking
+			{
+				Config: testAccContainerCluster_desiredEmulatedVersionComplete(clusterName, networkName, subnetworkName, fromVersion, targetVersion),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckContainerClusterEmulatedVersion(t, "google_container_cluster.primary"),
+				),
+			},
+			{
+				ResourceName:            "google_container_cluster.primary",
+				ImportState:             true,
+				ImportStateVerify:       true,
+				ImportStateVerifyIgnore: []string{"min_master_version", "deletion_protection"},
+			},
+		},
+	})
+}
+
+func testAccCheckContainerClusterEmulatedVersion(t *testing.T, resourceName string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		rs, ok := s.RootModule().Resources[resourceName]
+		if !ok {
+			return fmt.Errorf("not found: %s", resourceName)
+		}
+		if rs.Primary.ID == "" {
+			return fmt.Errorf("no GKE cluster ID is set in state")
+		}
+
+		config := acctest.GoogleProviderConfig(t)
+		clusterName := rs.Primary.Attributes["name"]
+		location := rs.Primary.Attributes["location"]
+		project := rs.Primary.Attributes["project"]
+
+		// Retrieve the live GKE cluster object from Google's REST GKE API client
+		cluster, err := container.NewClient(config, config.UserAgent).Projects.Locations.Clusters.Get(
+			fmt.Sprintf("projects/%s/locations/%s/clusters/%s", project, location, clusterName)).Do()
+		if err != nil {
+			return fmt.Errorf("failed to get GKE cluster details from API: %v", err)
+		}
+
+		// Verify GKE emulated version has advanced on the server side and is cleared post-upgrade
+		if cluster.CurrentEmulatedVersion != "" {
+			return fmt.Errorf("expected emulated version to be empty post-upgrade, but live GKE cluster has %q", cluster.CurrentEmulatedVersion)
+		}
+
+		return nil
+	}
+}
+
+func testAccContainerCluster_desiredEmulatedVersionBase(clusterName, networkName, subnetworkName, version string) string {
+	return fmt.Sprintf(`
+resource "google_container_cluster" "primary" {
+  name               = "%s"
+  location           = "us-central1-a"
+  initial_node_count = 1
+  min_master_version = "%s"
+  deletion_protection = false
+  network    = "%s"
+  subnetwork = "%s"
+
+  node_config {
+    machine_type = "e2-standard-2"
+  }
+}
+`, clusterName, version, networkName, subnetworkName)
+}
+
+func testAccContainerCluster_desiredEmulatedVersionSoak(clusterName, networkName, subnetworkName, fromVersion, targetVersion string) string {
+	return fmt.Sprintf(`
+resource "google_container_cluster" "primary" {
+  name               = "%s"
+  location           = "us-central1-a"
+  initial_node_count = 1
+  min_master_version = "%s"
+  deletion_protection = false
+  network    = "%s"
+  subnetwork = "%s"
+
+  desired_rollback_safe_upgrade {
+    control_plane_soak_duration = "90000s"
+  }
+
+  node_config {
+    machine_type = "e2-standard-2"
+  }
+}
+`, clusterName, targetVersion, networkName, subnetworkName)
+}
+
+func testAccContainerCluster_desiredEmulatedVersionComplete(clusterName, networkName, subnetworkName, fromVersion, targetVersion string) string {
+	return fmt.Sprintf(`
+resource "google_container_cluster" "primary" {
+  name               = "%s"
+  location           = "us-central1-a"
+  initial_node_count = 1
+  min_master_version = "%s"
+  deletion_protection = false
+  network    = "%s"
+  subnetwork = "%s"
+
+  desired_rollback_safe_upgrade {
+    control_plane_soak_duration = "90000s"
+  }
+
+  desired_emulated_version = "%s"
+
+  node_config {
+    machine_type = "e2-standard-2"
+  }
+}
+`, clusterName, targetVersion, networkName, subnetworkName, targetVersion)
+}