Support Self Service Maintenance feature

mmv1/products/sql/api.yaml

@@ -68,6 +68,22 @@ objects:
           - :FIRST_GEN
           - :SECOND_GEN
           - :EXTERNAL
+      - !ruby/object:Api::Type::String
+        name: 'maintenanceVersion'
+        output: true
+        description: |
+          The current software version on the instance. This attribute can not
+          be set during creation. Refer to available_maintenance_versions
+          attribute to see what maintenance_versions are available for upgrade.
+          When this attribute gets updated, it will cause an instance restart.
+
+      - !ruby/object:Api::Type::Array
+        name: 'availableMaintenanceVersions'
+        output: true
+        description: |
+          The list of all maintenance versions applicable on the instance. This
+          attribute can not be updated.
+        item_type: Api::Type::String
       - !ruby/object:Api::Type::String
         name: 'connectionName'
         description: |

mmv1/third_party/terraform/resources/resource_sql_database_instance.go.erb

@@ -443,7 +443,22 @@ is set to true.`,
 				Computed:    true,
 				Description: `The connection name of the instance to be used in connection strings. For example, when connecting with Cloud SQL Proxy.`,
 			},
-
+                        "maintenance_version": {
+                                Type:        schema.TypeString,
+                                Computed:    true,
+                                Optional:    true,
+                                DiffSuppressFunc: maintenanceVersionDiffSuppress,
+                                Description: `Maintenance version.`,
+                        },
+                        "available_maintenance_versions": {
+                                Type:        schema.TypeList,
+                                Computed:    true,
+                                Optional:    true,
+                                Elem: &schema.Schema{
+                                  Type: schema.TypeString,
+                                },
+                                Description: `Available Maintenance versions.`,
+                        },
 			"database_version": {
 				Type:        schema.TypeString,
 				Required:    true,
@@ -468,7 +483,6 @@ is set to true.`,
 				Sensitive:   true,
 				Description: `Initial root password. Required for MS SQL Server, ignored by MySQL and PostgreSQL.`,
 			},
-
 			"ip_address": {
 				Type:     schema.TypeList,
 				Computed: true,
@@ -1183,6 +1197,12 @@ func resourceSqlDatabaseInstanceRead(d *schema.ResourceData, meta interface{}) e
 	if err := d.Set("connection_name", instance.ConnectionName); err != nil {
 		return fmt.Errorf("Error setting connection_name: %s", err)
 	}
+        if err := d.Set("maintenance_version", instance.MaintenanceVersion); err != nil {
+                return fmt.Errorf("Error setting maintenance_version: %s", err)
+        }
+        if err := d.Set("available_maintenance_versions", instance.AvailableMaintenanceVersions); err != nil {
+                return fmt.Errorf("Error setting available_maintenance_version: %s", err)
+        }
 	if err := d.Set("service_account_email_address", instance.ServiceAccountEmailAddress); err != nil {
 		return fmt.Errorf("Error setting service_account_email_address: %s", err)
 	}
@@ -1261,8 +1281,14 @@ func resourceSqlDatabaseInstanceUpdate(d *schema.ResourceData, meta interface{})
 		return err
 	}
 
+        var maintenance_version string
+	if v, ok := d.GetOk("maintenance_version"); ok {
+		maintenance_version = v.(string)
+	}
+
 	// Update only updates the settings, so they are all we need to set.
 	instance := &sqladmin.DatabaseInstance{
+                MaintenanceVersion: maintenance_version,
 		Settings: expandSqlDatabaseInstanceSettings(d.Get("settings").([]interface{})),
 	}
 
@@ -1300,6 +1326,15 @@ func resourceSqlDatabaseInstanceUpdate(d *schema.ResourceData, meta interface{})
 	return resourceSqlDatabaseInstanceRead(d, meta)
 }
 
+func maintenanceVersionDiffSuppress(_, old, new string, _ *schema.ResourceData) bool {
+  if old > new {
+    log.Printf("[DEBUG] Maintenance version in configuration [%s] is older than current maintenance version [%s] on instance. Suppressing diff", new, old)
+    return true
+  } else {
+    return false
+  }
+}
+
 func resourceSqlDatabaseInstanceDelete(d *schema.ResourceData, meta interface{}) error {
 	config := meta.(*Config)
 	userAgent, err := generateUserAgentString(d, config.userAgent)

mmv1/third_party/terraform/website/docs/r/sql_database_instance.html.markdown

@@ -186,6 +186,8 @@ includes an up-to-date reference of supported versions.
     created. This is done because after a name is used, it cannot be reused for
     up to [one week](https://cloud.google.com/sql/docs/delete-instance).
 
+*  maintenance_version  - (Optional, Computed) The current software version on the instance. This attribute can not be set during creation. Refer to available_maintenance_versions attribute to see what maintenance_versions are available for upgrade. When this attribute gets updated, it will cause an instance restart.
+
 * `master_instance_name` - (Optional) The name of the existing instance that will
     act as the master in the replication setup. Note, this requires the master to
     have `binary_log_enabled` set, as well as existing backups.
@@ -425,6 +427,8 @@ instance.
 support accessing the [first address in the list in a terraform output](https://github.com/hashicorp/terraform-provider-google/issues/912)
 when the resource is configured with a `count`.
 
+*  available_maintenance_versions  - The list of all maintenance versions applicable on the instance. This attribute can not be updated.
+
 * `public_ip_address` - The first public (`PRIMARY`) IPv4 address assigned. This is
 a workaround for an [issue fixed in Terraform 0.12](https://github.com/hashicorp/terraform/issues/17048)
 but also provides a convenient way to access an IP of a specific type without