feat(aws): Support rollback of a disabled server group (#5077)

A disabled server group can be rolled back iff at least one enabled
server group exists in the same cluster.

The largest enabled server group in the cluster will will be selected as
the rollback source.

depends on spinnaker/clouddriver#2455

app/scripts/modules/amazon/src/serverGroup/details/AmazonServerGroupActions.tsx

@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { BindAll } from 'lodash-decorators';
 import { Dropdown, Tooltip } from 'react-bootstrap';
-import { get, find, filter } from 'lodash';
+import { get, find, filter, orderBy } from 'lodash';
 
 import { IOwnerOption, IServerGroupActionsProps, IServerGroupJob, NgReact, ReactInjector, SETTINGS } from '@spinnaker/core';
 
@@ -26,6 +26,24 @@ export class AmazonServerGroupActions extends React.Component<IAmazonServerGroup
     return false;
   }
 
+  private isRollbackEnabled(): boolean {
+    const { app, serverGroup } = this.props;
+
+    if (!serverGroup.isDisabled) {
+      // enabled server groups are always a candidate for rollback
+      return true;
+    }
+
+    // if the server group selected for rollback is disabled, ensure that at least one enabled server group exists
+    return app.getDataSource('serverGroups').data.some((g: IAmazonServerGroup) =>
+      g.cluster === serverGroup.cluster &&
+      g.region === serverGroup.region &&
+      g.account === serverGroup.account &&
+      !g.isDisabled
+    );
+  }
+
+
   private hasDisabledInstances(): boolean {
     // server group may have disabled instances (out of service) but NOT itself be disabled
     return this.props.serverGroup.isDisabled || (get(this.props.serverGroup, 'instanceCounts.outOfService', 0) > 0);
@@ -140,23 +158,45 @@ export class AmazonServerGroupActions extends React.Component<IAmazonServerGroup
   };
 
   private rollbackServerGroup(): void {
-    const { app, serverGroup } = this.props;
+    const { app } = this.props;
+
+    let serverGroup: IAmazonServerGroup = this.props.serverGroup;
+    let previousServerGroup: IAmazonServerGroup;
+    let allServerGroups = app.getDataSource('serverGroups').data.filter((g: IAmazonServerGroup) =>
+      g.cluster === serverGroup.cluster &&
+      g.region === serverGroup.region &&
+      g.account === serverGroup.account
+    );
+
+    if (serverGroup.isDisabled) {
+      // if the selected server group is disabled, it represents the server group that should be _rolled back to_
+      previousServerGroup = serverGroup;
+
+      /*
+       * Find an existing server group to rollback, prefer the largest enabled server group.
+       *
+       * isRollbackEnabled() ensures that at least one enabled server group exists.
+       */
+      serverGroup = orderBy(
+        allServerGroups.filter((g: IAmazonServerGroup) => g.name !== previousServerGroup.name && !g.isDisabled),
+        ['instanceCounts.total'], ['desc']
+      )[0] as IAmazonServerGroup;
+    }
+
+    // the set of all server groups should not include the server group selected for rollback
+    allServerGroups = allServerGroups.filter((g: IAmazonServerGroup) => g.name !== serverGroup.name);
 
     ReactInjector.modalService.open({
       templateUrl: ReactInjector.overrideRegistry.getTemplate('aws.rollback.modal', require('./rollback/rollbackServerGroup.html')),
       controller: 'awsRollbackServerGroupCtrl as ctrl',
       resolve: {
         serverGroup: () => serverGroup,
+        previousServerGroup: () => previousServerGroup,
         disabledServerGroups: () => {
           const cluster = find(app.clusters, { name: serverGroup.cluster, account: serverGroup.account, serverGroups: [] });
           return filter(cluster.serverGroups, { isDisabled: true, region: serverGroup.region });
         },
-        allServerGroups: () => app.getDataSource('serverGroups').data.filter((g: IAmazonServerGroup) =>
-          g.cluster === serverGroup.cluster &&
-          g.region === serverGroup.region &&
-          g.account === serverGroup.account &&
-          g.name !== serverGroup.name
-        ),
+        allServerGroups: () => allServerGroups,
         application: () => app
       }
     });
@@ -200,8 +240,8 @@ export class AmazonServerGroupActions extends React.Component<IAmazonServerGroup
           Server Group Actions
         </Dropdown.Toggle>
         <Dropdown.Menu className="dropdown-menu">
-          {!serverGroup.isDisabled && <li><a className="clickable" onClick={this.rollbackServerGroup}>Rollback</a></li>}
-          {!serverGroup.isDisabled && <li role="presentation" className="divider"/>}
+          {this.isRollbackEnabled() && <li><a className="clickable" onClick={this.rollbackServerGroup}>Rollback</a></li>}
+          {this.isRollbackEnabled() && <li role="presentation" className="divider"/>}
           <li><a className="clickable" onClick={this.resizeServerGroup}>Resize</a></li>
           {!serverGroup.isDisabled && <li><a className="clickable" onClick={this.disableServerGroup}>Disable</a></li>}
           {this.hasDisabledInstances() && !this.isEnableLocked() && <li><a className="clickable" onClick={this.enableServerGroup}>Enable</a></li>}

app/scripts/modules/amazon/src/serverGroup/details/rollback/rollbackServerGroup.controller.js

@@ -11,7 +11,9 @@ module.exports = angular.module('spinnaker.amazon.serverGroup.details.rollback.c
     ])
     .controller('awsRollbackServerGroupCtrl', function ($scope, $uibModalInstance, serverGroupWriter,
                                                         taskMonitorBuilder,
-                                                        application, serverGroup, disabledServerGroups, allServerGroups) {
+                                                        application,
+                                                        serverGroup, previousServerGroup,
+                                                        disabledServerGroups, allServerGroups) {
       $scope.serverGroup = serverGroup;
       $scope.disabledServerGroups = disabledServerGroups.sort((a, b) => b.name.localeCompare(a.name));
       $scope.allServerGroups = allServerGroups.sort((a, b) => b.name.localeCompare(a.name));
@@ -54,6 +56,7 @@ module.exports = angular.module('spinnaker.amazon.serverGroup.details.rollback.c
         rollbackType: rollbackType,
         rollbackContext: {
           rollbackServerGroupName: serverGroup.name,
+          restoreServerGroupName: previousServerGroup ? previousServerGroup.name : undefined,
           targetHealthyRollbackPercentage: healthyPercent
         }
       };

app/scripts/modules/amazon/src/serverGroup/details/rollback/rollbackServerGroup.html

@@ -10,7 +10,7 @@ <h3>Rollback {{serverGroup.name}}</h3>
         <div class="col-sm-3 sm-label-right">
           Restore to
         </div>
-        <div class="col-sm-8">
+        <div class="col-md-7">
           <ui-select ng-model="command.rollbackContext.restoreServerGroupName"
                      class="form-control input-sm"
                      ng-if="command.rollbackType === 'EXPLICIT'">
@@ -42,9 +42,7 @@ <h3>Rollback {{serverGroup.name}}</h3>
         </div>
       </div>
 
-      <div class="row">
-        <task-reason command="command"></task-reason>
-      </div>
+      <task-reason command="command"></task-reason>
 
       <div class="row">
         <div class="col-sm-11 col-sm-offset-1">