Add the ability to use the GKE recurring maintenance window in beta.

Signed-off-by: Modular Magician <[email protected]>

google/resource_container_cluster.go

@@ -311,6 +311,7 @@ func resourceContainerCluster() *schema.Resource {
 						"daily_maintenance_window": {
 							Type:     schema.TypeList,
 							Required: true,
+
 							MaxItems: 1,
 							Elem: &schema.Resource{
 								Schema: map[string]*schema.Schema{
@@ -763,7 +764,7 @@ func resourceContainerClusterCreate(d *schema.ResourceData, meta interface{}) er
 	cluster := &containerBeta.Cluster{
 		Name:                           clusterName,
 		InitialNodeCount:               int64(d.Get("initial_node_count").(int)),
-		MaintenancePolicy:              expandMaintenancePolicy(d.Get("maintenance_policy")),
+		MaintenancePolicy:              expandMaintenancePolicy(d, meta),
 		MasterAuthorizedNetworksConfig: expandMasterAuthorizedNetworksConfig(d.Get("master_authorized_networks_config")),
 		InitialClusterVersion:          d.Get("min_master_version").(string),
 		ClusterIpv4Cidr:                d.Get("cluster_ipv4_cidr").(string),
@@ -1117,15 +1118,8 @@ func resourceContainerClusterUpdate(d *schema.ResourceData, meta interface{}) er
 	}
 
 	if d.HasChange("maintenance_policy") {
-		var req *containerBeta.SetMaintenancePolicyRequest
-		if mp, ok := d.GetOk("maintenance_policy"); ok {
-			req = &containerBeta.SetMaintenancePolicyRequest{
-				MaintenancePolicy: expandMaintenancePolicy(mp),
-			}
-		} else {
-			req = &containerBeta.SetMaintenancePolicyRequest{
-				NullFields: []string{"MaintenancePolicy"},
-			}
+		req := &containerBeta.SetMaintenancePolicyRequest{
+			MaintenancePolicy: expandMaintenancePolicy(d, meta),
 		}
 
 		updateF := func() error {
@@ -1736,22 +1730,48 @@ func expandIPAllocationPolicy(configured interface{}) *containerBeta.IPAllocatio
 	}
 }
 
-func expandMaintenancePolicy(configured interface{}) *containerBeta.MaintenancePolicy {
+func expandMaintenancePolicy(d *schema.ResourceData, meta interface{}) *containerBeta.MaintenancePolicy {
+	config := meta.(*Config)
+	// We have to perform a full Get() as part of this, to get the fingerprint.  We can't do this
+	// at any other time, because the fingerprint update might happen between plan and apply.
+	// We can omit error checks, since to have gotten this far, a project is definitely configured.
+	project, _ := getProject(d, config)
+	location, _ := getLocation(d, config)
+	clusterName := d.Get("name").(string)
+	name := containerClusterFullName(project, location, clusterName)
+	cluster, _ := config.clientContainerBeta.Projects.Locations.Clusters.Get(name).Do()
+	resourceVersion := ""
+	// If the cluster doesn't exist or if there is a read error of any kind, we will pass in an empty
+	// resourceVersion.  If there happens to be a change to maintenance policy, we will fail at that
+	// point.  This is a compromise between code cleanliness and a slightly worse user experience in
+	// an unlikely error case - we choose code cleanliness.
+	if cluster != nil && cluster.MaintenancePolicy != nil {
+		resourceVersion = cluster.MaintenancePolicy.ResourceVersion
+	}
+
+	configured := d.Get("maintenance_policy")
 	l := configured.([]interface{})
 	if len(l) == 0 || l[0] == nil {
-		return nil
+		return &containerBeta.MaintenancePolicy{
+			ResourceVersion: resourceVersion,
+		}
 	}
-
 	maintenancePolicy := l[0].(map[string]interface{})
-	dailyMaintenanceWindow := maintenancePolicy["daily_maintenance_window"].([]interface{})[0].(map[string]interface{})
-	startTime := dailyMaintenanceWindow["start_time"].(string)
-	return &containerBeta.MaintenancePolicy{
-		Window: &containerBeta.MaintenanceWindow{
-			DailyMaintenanceWindow: &containerBeta.DailyMaintenanceWindow{
-				StartTime: startTime,
+
+	if dailyMaintenanceWindow, ok := maintenancePolicy["daily_maintenance_window"]; ok && len(dailyMaintenanceWindow.([]interface{})) > 0 {
+		dmw := dailyMaintenanceWindow.([]interface{})[0].(map[string]interface{})
+		startTime := dmw["start_time"].(string)
+		return &containerBeta.MaintenancePolicy{
+			Window: &containerBeta.MaintenanceWindow{
+				DailyMaintenanceWindow: &containerBeta.DailyMaintenanceWindow{
+					StartTime: startTime,
+				},
 			},
-		},
+			ResourceVersion: resourceVersion,
+		}
 	}
+
+	return nil
 }
 
 func expandMasterAuth(configured interface{}) *containerBeta.MasterAuth {
@@ -1969,19 +1989,23 @@ func flattenIPAllocationPolicy(c *containerBeta.Cluster, d *schema.ResourceData,
 }
 
 func flattenMaintenancePolicy(mp *containerBeta.MaintenancePolicy) []map[string]interface{} {
-	if mp == nil || mp.Window == nil || mp.Window.DailyMaintenanceWindow == nil {
+	if mp == nil || mp.Window == nil {
 		return nil
 	}
-	return []map[string]interface{}{
-		{
-			"daily_maintenance_window": []map[string]interface{}{
-				{
-					"start_time": mp.Window.DailyMaintenanceWindow.StartTime,
-					"duration":   mp.Window.DailyMaintenanceWindow.Duration,
+	if mp.Window.DailyMaintenanceWindow != nil {
+		return []map[string]interface{}{
+			{
+				"daily_maintenance_window": []map[string]interface{}{
+					{
+						"start_time": mp.Window.DailyMaintenanceWindow.StartTime,
+						"duration":   mp.Window.DailyMaintenanceWindow.Duration,
+					},
 				},
 			},
-		},
+		}
 	}
+
+	return nil
 }
 
 func flattenMasterAuth(ma *containerBeta.MasterAuth) []map[string]interface{} {

google/resource_container_cluster_test.go

@@ -2355,8 +2355,8 @@ resource "google_container_cluster" "cidr_error_overlap" {
   initial_node_count = 1
 
   ip_allocation_policy {
-    cluster_ipv4_cidr_block = "10.0.0.0/16"
-    services_ipv4_cidr_block = "10.1.0.0/16"
+	cluster_ipv4_cidr_block = "10.0.0.0/16"
+	services_ipv4_cidr_block = "10.1.0.0/16"
   }
 }
 `, initConfig, secondCluster)

website/docs/r/container_cluster.html.markdown

@@ -402,7 +402,7 @@ The `authenticator_groups_config` block supports:
 
 The `maintenance_policy` block supports:
 
-* `daily_maintenance_window` - (Required) Time window specified for daily maintenance operations.
+* `daily_maintenance_window` - (Required in GA, Optional in Beta) Time window specified for daily maintenance operations.
     Specify `start_time` in [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) format "HH:MM”,
     where HH : \[00-23\] and MM : \[00-59\] GMT. For example:
 
@@ -414,6 +414,26 @@ maintenance_policy {
 }
 ```
 
+* `recurring_window` - (Optional, [Beta](https://terraform.io/docs/providers/google/provider_versions.html)) Time window for
+recurring maintenance operations.
+
+Specify `start_time` and `end_time` in [RFC3339](https://www.ietf.org/rfc/rfc3339.txt) date format.  The start time's date is
+the initial date that the window starts, and the end time is used for calculating duration.  Specify `recurrence` in
+[RFC5545](https://tools.ietf.org/html/rfc5545#section-3.8.5.3) RRULE format, to specify when this recurs.
+
+For example:
+```
+maintenance_policy {
+  recurring_window {
+    start_time = "2019-01-01T03:00"
+    end_time = "2019-01-01T06:00"
+    recurrence = "FREQ=DAILY"
+  }
+}
+```
+
+In beta, one or the other of `recurring_window` and `daily_maintenance_window` is required if a `maintenance_policy` block is supplied.
+
 The `ip_allocation_policy` block supports:
 
 * `use_ip_aliases` - (Optional) Whether alias IPs will be used for pod IPs in