Add notifications plugin, offering basic email service (elastic#143303)

* Misc enhancements following PR comments

* Adding functional tests

* Fixing types

* Fixing tests

* Removing unnecessary Promise.all

* Cleanup

* Misc fixes and simplifications

* Add missing tsconfig.json

* [CI] Auto-commit changed files from 'node scripts/build_plugin_list_docs'

* Add dependency to Actions plugin in tsconfig.json

* Separate setup logic from start logic

* Fix bulkEnqueueExecution params structure

* Update README

* Add UTs

* Check license type >platinum for email notifications

* Fix incorrect UTs

* Import types when possible

* Misc enhancements and code cleanup

* Transform factory => provider, update start contract

* Code cleanup, update README

* Fix TS error

* Fix CI types error

* Address PR remarks

* Address PR remarks #2

Co-authored-by: Ying Mao <ying.mao@elastic.co>
Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

.github/CODEOWNERS

@@ -89,6 +89,7 @@
 /x-pack/test/search_sessions_integration/ @elastic/kibana-app-services
 /test/plugin_functional/test_suites/panel_actions @elastic/kibana-app-services
 /test/plugin_functional/test_suites/data_plugin @elastic/kibana-app-services
+/x-pack/plugins/notifications/ @elastic/kibana-app-services
 
 ### Observability Plugins
 

docs/developer/plugin-list.asciidoc

@@ -589,6 +589,10 @@ Elastic.
 |This plugin allows for other plugins to add data to Kibana stack monitoring documents.
 
 
+|{kib-repo}blob/{branch}/x-pack/plugins/notifications/README.md[notifications]
+|The Notifications plugin provides a set of services to help Solutions and plugins send notifications to users.
+
+
 |{kib-repo}blob/{branch}/x-pack/plugins/observability/README.md[observability]
 |This plugin provides shared components and services for use across observability solutions, as well as the observability landing page UI.
 

src/plugins/telemetry/README.md

@@ -51,14 +51,14 @@ To use the exposed plugin start and setup contracts:
 
 import { TelemetryPluginsStart } from '../telemetry/server`;
 
-interface MyPlyginStartDeps {
+interface MyPluginStartDeps {
   telemetry?: TelemetryPluginsStart;
 }
 
 class MyPlugin {
   public async start(
     core: CoreStart,
-    { telemetry }: MyPlyginStartDeps
+    { telemetry }: MyPluginStartDeps
   ) {
     const isOptedIn = await telemetry?.getIsOptedIn();
     ...

tsconfig.base.json

@@ -1104,6 +1104,8 @@
       "@kbn/monitoring-collection-plugin/*": ["x-pack/plugins/monitoring_collection/*"],
       "@kbn/monitoring-plugin": ["x-pack/plugins/monitoring"],
       "@kbn/monitoring-plugin/*": ["x-pack/plugins/monitoring/*"],
+      "@kbn/notifications-plugin": ["x-pack/plugins/notifications"],
+      "@kbn/notifications-plugin/*": ["x-pack/plugins/notifications/*"],
       "@kbn/observability-plugin": ["x-pack/plugins/observability"],
       "@kbn/observability-plugin/*": ["x-pack/plugins/observability/*"],
       "@kbn/osquery-plugin": ["x-pack/plugins/osquery"],

x-pack/plugins/actions/server/mocks.ts

@@ -39,7 +39,7 @@ const createStartMock = () => {
     isActionTypeEnabled: jest.fn(),
     isActionExecutable: jest.fn(),
     getActionsClientWithRequest: jest.fn().mockResolvedValue(actionsClientMock.create()),
-    getUnsecuredActionsClient: jest.fn().mockResolvedValue(unsecuredActionsClientMock.create()),
+    getUnsecuredActionsClient: jest.fn().mockReturnValue(unsecuredActionsClientMock.create()),
     getActionsAuthorizationWithRequest: jest
       .fn()
       .mockReturnValue(actionsAuthorizationMock.create()),

x-pack/plugins/actions/server/plugin.ts

@@ -102,7 +102,7 @@ import { IServiceAbstract, SubActionConnectorType } from './sub_action_framework
 import { SubActionConnector } from './sub_action_framework/sub_action_connector';
 import { CaseConnector } from './sub_action_framework/case';
 import {
-  IUnsecuredActionsClient,
+  type IUnsecuredActionsClient,
   UnsecuredActionsClient,
 } from './unsecured_actions_client/unsecured_actions_client';
 import { createBulkUnsecuredExecutionEnqueuerFunction } from './create_unsecured_execute_function';

x-pack/plugins/actions/server/unsecured_actions_client/unsecured_actions_client.mock.ts

@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import { IUnsecuredActionsClient } from './unsecured_actions_client';
+import type { IUnsecuredActionsClient } from './unsecured_actions_client';
 
 export type UnsecuredActionsClientMock = jest.Mocked<IUnsecuredActionsClient>;
 

x-pack/plugins/notifications/README.md

@@ -0,0 +1,70 @@
+# Kibana Notifications Plugin
+
+The Notifications plugin provides a set of services to help Solutions and plugins send notifications to users.
+
+## Notifications Plugin public API
+
+### Start
+
+The `start` function exposes the following interface:
+
+- `isEmailServiceAvailable(): boolean`:
+  A function to check whether the deployment is properly configured and the EmailService can be correctly retrieved.
+- `getEmailService(): EmailService`:
+- A function to get the basic EmailService, which can be used to send plain text emails. If the EmailService is not available, trying to retrieve it will result in an Exception.
+
+
+### Usage
+
+To use the exposed plugin start contract:
+
+1. Make sure `notifications` is in your `optionalPlugins` in the `kibana.json` file:
+
+```json5
+// <plugin>/kibana.json
+{
+"id": "...",
+"requiredPlugins": ["notifications"]
+}
+```
+
+2. Use the exposed contract:
+
+```ts
+// <plugin>/server/plugin.ts
+import { NotificationsPluginStart } from '../notifications/server`;
+
+interface MyPluginStartDeps {
+  notifications?: NotificationsPluginStart;
+}
+
+class MyPlugin {
+  public start(
+    core: CoreStart,
+    { notifications }: MyPluginStartDeps
+  ) {
+    if (notifications.isEmailServiceAvailable()) {
+      const emailService = notifications.getEmailService();
+      emailService.sendPlainTextEmail({
+          to: 'foo@bar.com',
+          subject: 'Some subject',
+          message: 'Hello world!',
+      });
+    }
+    ...
+  }
+}
+```
+
+### Requirements
+
+- This plugin currently depends on the `'actions'` plugin, as it uses `Connectors` under the hood.
+- Note also that for each notification channel the corresponding connector must be preconfigured. E.g. to enable email notifications, an `Email` connector must exist in the system.
+- Once the appropriate connectors are preconfigured in `kibana.yaml`, you can configure the `'notifications'` plugin by adding:
+
+  ```yaml
+  notifications:
+    connectors:
+      default:
+        email: elastic-cloud-email  # The identifier of the configured connector
+  ```

x-pack/plugins/notifications/common/index.ts

@@ -0,0 +1,8 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+export const PLUGIN_ID = 'notifications';

x-pack/plugins/notifications/jest.config.js

@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+module.exports = {
+  preset: '@kbn/test/jest_node',
+  rootDir: '../../..',
+  roots: ['<rootDir>/x-pack/plugins/notifications'],
+  coverageDirectory: '<rootDir>/target/kibana-coverage/jest/x-pack/plugins/notifications',
+  coverageReporters: ['text', 'html'],
+  collectCoverageFrom: ['<rootDir>/x-pack/plugins/notifications/{common,server}/**/*.{js,ts,tsx}'],
+};

x-pack/plugins/notifications/kibana.json

@@ -0,0 +1,12 @@
+{
+  "id": "notifications",
+   "owner": {
+    "name": "App Services",
+    "githubTeam": "kibana-app-services"
+  },
+  "version": "kibana",
+  "server": true,
+  "ui": false,
+  "requiredPlugins": ["actions", "licensing"],
+  "optionalPlugins": []
+}

x-pack/plugins/notifications/server/config/config.ts

@@ -0,0 +1,29 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { schema, type TypeOf } from '@kbn/config-schema';
+import type { PluginConfigDescriptor } from '@kbn/core/server';
+
+export const configSchema = schema.object(
+  {
+    connectors: schema.maybe(
+      schema.object({
+        default: schema.maybe(
+          schema.object({
+            email: schema.maybe(schema.string()),
+          })
+        ),
+      })
+    ),
+  },
+  { defaultValue: {} }
+);
+export type NotificationsConfigType = TypeOf<typeof configSchema>;
+
+export const config: PluginConfigDescriptor<NotificationsConfigType> = {
+  schema: configSchema,
+};

x-pack/plugins/notifications/server/config/index.ts

@@ -0,0 +1,8 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+export { type NotificationsConfigType, config } from './config';

x-pack/plugins/notifications/server/index.ts

@@ -0,0 +1,18 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import type { PluginInitializerContext } from '@kbn/core/server';
+import { NotificationsPlugin } from './plugin';
+export { config } from './config';
+
+//  This exports static code and TypeScript types,
+//  as well as, Kibana Platform `plugin()` initializer.
+export type { NotificationsPluginStart } from './types';
+
+export function plugin(initializerContext: PluginInitializerContext) {
+  return new NotificationsPlugin(initializerContext);
+}

x-pack/plugins/notifications/server/mocks.ts

@@ -0,0 +1,52 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import type { PublicMethodsOf } from '@kbn/utility-types';
+import type { EmailService } from './services';
+import type { NotificationsPluginStart } from './types';
+import type { NotificationsPlugin } from './plugin';
+
+const emailServiceMock: jest.Mocked<EmailService> = {
+  sendPlainTextEmail: jest.fn(),
+};
+
+const createEmailServiceMock = () => {
+  return emailServiceMock;
+};
+
+const startMock: jest.Mocked<NotificationsPluginStart> = {
+  isEmailServiceAvailable: jest.fn(),
+  getEmailService: jest.fn(createEmailServiceMock),
+};
+
+const createStartMock = () => {
+  return startMock;
+};
+
+const notificationsPluginMock: jest.Mocked<PublicMethodsOf<NotificationsPlugin>> = {
+  setup: jest.fn(),
+  start: jest.fn(createStartMock) as jest.Mock<NotificationsPluginStart>,
+  stop: jest.fn(),
+};
+
+const createNotificationsPluginMock = () => {
+  return notificationsPluginMock;
+};
+
+export const notificationsMock = {
+  createNotificationsPlugin: createNotificationsPluginMock,
+  createEmailService: createEmailServiceMock,
+  createStart: createStartMock,
+  clear: () => {
+    emailServiceMock.sendPlainTextEmail.mockClear();
+    startMock.getEmailService.mockClear();
+    startMock.isEmailServiceAvailable.mockClear();
+    notificationsPluginMock.setup.mockClear();
+    notificationsPluginMock.start.mockClear();
+    notificationsPluginMock.stop.mockClear();
+  },
+};

x-pack/plugins/notifications/server/plugin.test.ts

@@ -0,0 +1,107 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { coreMock } from '@kbn/core/server/mocks';
+import { actionsMock } from '@kbn/actions-plugin/server/mocks';
+import type { NotificationsConfigType } from './config';
+import { NotificationsPlugin } from './plugin';
+import { licensingMock } from '@kbn/licensing-plugin/server/mocks';
+import { EmailServiceProvider } from './services/connectors_email_service_provider';
+import { EmailServiceStart } from './services';
+
+jest.mock('./services/connectors_email_service_provider');
+
+const emailServiceProviderMock = EmailServiceProvider as jest.MockedClass<
+  typeof EmailServiceProvider
+>;
+
+const validConnectorConfig = {
+  connectors: {
+    default: {
+      email: 'validConnectorId',
+    },
+  },
+};
+
+const createNotificationsPlugin = (config: NotificationsConfigType) => {
+  const context = coreMock.createPluginInitializerContext<NotificationsConfigType>(config);
+  const plugin = new NotificationsPlugin(context);
+  const coreSetup = coreMock.createSetup();
+  const coreStart = coreMock.createStart();
+
+  const actionsSetup = actionsMock.createSetup();
+  actionsSetup.isPreconfiguredConnector.mockImplementationOnce(
+    (connectorId) => connectorId === 'validConnectorId'
+  );
+  const pluginSetup = {
+    actions: actionsSetup,
+    licensing: licensingMock.createSetup(),
+  };
+
+  const actionsStart = actionsMock.createStart();
+  const pluginStart = {
+    actions: actionsStart,
+    licensing: licensingMock.createStart(),
+  };
+
+  return {
+    context,
+    logger: context.logger.get(),
+    plugin,
+    coreSetup,
+    coreStart,
+    actionsSetup,
+    pluginSetup,
+    actionsStart,
+    pluginStart,
+  };
+};
+
+describe('Notifications Plugin', () => {
+  beforeEach(() => emailServiceProviderMock.mockClear());
+
+  it('should create an EmailServiceProvider passing in the configuration and logger from the initializer context', () => {
+    const { logger } = createNotificationsPlugin(validConnectorConfig);
+    expect(emailServiceProviderMock).toHaveBeenCalledTimes(1);
+    expect(emailServiceProviderMock).toHaveBeenCalledWith(validConnectorConfig, logger);
+  });
+
+  describe('setup()', () => {
+    it('should call setup() on the created EmailServiceProvider, passing in the setup plugin dependencies', () => {
+      const { plugin, coreSetup, pluginSetup } = createNotificationsPlugin(validConnectorConfig);
+      plugin.setup(coreSetup, pluginSetup);
+      expect(emailServiceProviderMock.mock.instances[0].setup).toHaveBeenCalledTimes(1);
+      expect(emailServiceProviderMock.mock.instances[0].setup).toBeCalledWith(pluginSetup);
+    });
+  });
+
+  describe('start()', () => {
+    it('should call start() on the created EmailServiceProvider, passing in the setup plugin dependencies', () => {
+      const { plugin, coreStart, pluginStart } = createNotificationsPlugin(validConnectorConfig);
+      plugin.start(coreStart, pluginStart);
+      expect(emailServiceProviderMock.mock.instances[0].start).toHaveBeenCalledTimes(1);
+      expect(emailServiceProviderMock.mock.instances[0].start).toBeCalledWith(pluginStart);
+    });
+
+    it('should return EmailServiceProvider.start() contract as part of its contract', () => {
+      const { plugin, coreStart, pluginStart } = createNotificationsPlugin(validConnectorConfig);
+
+      const emailStart: EmailServiceStart = {
+        getEmailService: jest.fn(),
+        isEmailServiceAvailable: jest.fn(),
+      };
+
+      const providerMock = emailServiceProviderMock.mock
+        .instances[0] as jest.Mocked<EmailServiceProvider>;
+      providerMock.start.mockReturnValue(emailStart);
+      const start = plugin.start(coreStart, pluginStart);
+      expect(emailServiceProviderMock.mock.instances[0].start).toHaveBeenCalledTimes(1);
+      expect(emailServiceProviderMock.mock.instances[0].start).toBeCalledWith(pluginStart);
+      expect(start).toEqual(expect.objectContaining(emailStart));
+    });
+  });
+});