[ResponseOps][Flapping] add flapping state to alert context for action parameters (#147136)

Resolves https://github.com/elastic/kibana/issues/146613

## Summary
Makes flapping indicator for an alert available in the context variables
for action mustache templates under `alert.flapping`
Let me know if we want to change this to be something else

### Checklist

- [x]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

### To verify

- Create a new rule with a connector
- Add the new field Add `{{alert.flapping}}` to the your alert message,
and verify that it is in the alert output.

docs/user/alerting/create-and-manage-rules.asciidoc

@@ -134,6 +134,8 @@ Using the https://mustache.github.io/[Mustache] template syntax `{{variable name
 `alert.actionGroup`:: The ID of the action group of the alert that scheduled the action.
 `alert.actionSubgroup`:: The action subgroup of the alert that scheduled the action.
 `alert.actionGroupName`:: The name of the action group of the alert that scheduled the action.
+`alert.flapping`:: A flag on the alert that indicates whether the alert status is changing repeatedly.
+
 `kibanaBaseUrl`:: The configured <<server-publicBaseUrl, `server.publicBaseUrl`>>. If not configured, this will be empty.
 
 [role="screenshot"]

x-pack/plugins/alerting/server/task_runner/execution_handler.ts

@@ -208,6 +208,7 @@ export class ExecutionHandler<
               alertParams: this.rule.params,
               actionParams: action.params,
               ruleUrl: this.buildRuleUrl(spaceId),
+              flapping: alert.getFlapping(),
             }),
           }),
         };

x-pack/plugins/alerting/server/task_runner/transform_action_params.test.ts

@@ -48,6 +48,7 @@ test('skips non string parameters', () => {
     alertParams: {
       foo: 'test',
     },
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -82,6 +83,7 @@ test('missing parameters get emptied out', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -111,6 +113,7 @@ test('context parameters are passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -139,6 +142,7 @@ test('state parameters are passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -167,6 +171,7 @@ test('alertId is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -195,6 +200,7 @@ test('alertName is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -223,6 +229,7 @@ test('tags is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -250,6 +257,7 @@ test('undefined tags is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -278,6 +286,7 @@ test('empty tags is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -306,6 +315,7 @@ test('spaceId is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -334,6 +344,7 @@ test('alertInstanceId is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -362,6 +373,7 @@ test('alertActionGroup is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -390,6 +402,7 @@ test('alertActionGroupName is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -418,6 +431,7 @@ test('rule variables are passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -446,6 +460,7 @@ test('rule alert variables are passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
     Object {
@@ -475,6 +490,7 @@ test('date is passed to templates', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   const dateAfter = Date.now();
   const dateVariable = new Date(`${result.message}`).valueOf();
@@ -505,6 +521,7 @@ test('works recursively', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -537,6 +554,7 @@ test('works recursively with arrays', () => {
     alertActionGroup: 'action-group',
     alertActionGroupName: 'Action Group',
     alertParams: {},
+    flapping: false,
   });
   expect(result).toMatchInlineSnapshot(`
         Object {
@@ -548,3 +566,32 @@ test('works recursively with arrays', () => {
         }
     `);
 });
+
+test('flapping is passed to templates', () => {
+  const actionParams = {
+    message: 'Value "{{alert.flapping}}" exists',
+  };
+  const result = transformActionParams({
+    actionsPlugin,
+    actionTypeId,
+    actionParams,
+    state: {},
+    context: {},
+    alertId: '1',
+    alertType: 'rule-type-id',
+    actionId: 'action-id',
+    alertName: 'alert-name',
+    tags: ['tag-A', 'tag-B'],
+    spaceId: 'spaceId-A',
+    alertInstanceId: '2',
+    alertActionGroup: 'action-group',
+    alertActionGroupName: 'Action Group',
+    alertParams: {},
+    flapping: true,
+  });
+  expect(result).toMatchInlineSnapshot(`
+    Object {
+      "message": "Value \\"true\\" exists",
+    }
+  `);
+});

x-pack/plugins/alerting/server/task_runner/transform_action_params.ts

@@ -31,6 +31,7 @@ interface TransformActionParamsOptions {
   kibanaBaseUrl?: string;
   context: AlertInstanceContext;
   ruleUrl?: string;
+  flapping: boolean;
 }
 
 export function transformActionParams({
@@ -51,6 +52,7 @@ export function transformActionParams({
   kibanaBaseUrl,
   alertParams,
   ruleUrl,
+  flapping,
 }: TransformActionParamsOptions): RuleActionParams {
   // when the list of variables we pass in here changes,
   // the UI will need to be updated as well; see:
@@ -80,6 +82,7 @@ export function transformActionParams({
       id: alertInstanceId,
       actionGroup: alertActionGroup,
       actionGroupName: alertActionGroupName,
+      flapping,
     },
   };
   return actionsPlugin.renderActionParameterTemplates(

x-pack/plugins/triggers_actions_ui/public/application/lib/action_variables.test.ts

@@ -63,6 +63,10 @@ const expectedTransformResult = [
       'The human readable name of the action group of the alert that scheduled actions for the rule.',
     name: 'alert.actionGroupName',
   },
+  {
+    description: 'A flag on the alert that indicates whether the alert is flapping.',
+    name: 'alert.flapping',
+  },
   {
     description: 'The configured server.publicBaseUrl value or empty string if not configured.',
     name: 'kibanaBaseUrl',

x-pack/plugins/triggers_actions_ui/public/application/lib/action_variables.ts

@@ -47,6 +47,7 @@ export enum AlertProvidedActionVariables {
   alertActionGroup = 'alert.actionGroup',
   alertActionGroupName = 'alert.actionGroupName',
   alertActionSubgroup = 'alert.actionSubgroup',
+  alertFlapping = 'alert.flapping',
 }
 
 export enum LegacyAlertProvidedActionVariables {
@@ -156,6 +157,14 @@ function getAlwaysProvidedActionVariables(): ActionVariable[] {
     ),
   });
 
+  result.push({
+    name: AlertProvidedActionVariables.alertFlapping,
+    description: i18n.translate('xpack.triggersActionsUI.actionVariables.alertFlappingLabel', {
+      defaultMessage:
+        'A flag on the alert that indicates whether the alert status is changing repeatedly.',
+    }),
+  });
+
   result.push({
     name: 'kibanaBaseUrl',
     description: i18n.translate('xpack.triggersActionsUI.actionVariables.kibanaBaseUrlLabel', {