async-import plugins in the server side (elastic#170856)

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

dev_docs/key_concepts/anatomy_of_a_plugin.mdx

@@ -122,7 +122,7 @@ If you are developing in TypeScript (which we recommend), you will need to add a
 core capabilities as an argument. It should return an instance of its plugin class for Kibana to load.
 
 ```ts
-import type { PluginInitializerContext } from '@kbn/core/server';
+import type { PluginInitializerContext } from '@kbn/core/public';
 import { DemoPlugin } from './plugin';
 
 export function plugin(initializerContext: PluginInitializerContext) {
@@ -177,7 +177,16 @@ export class DemoPlugin implements Plugin {
 
 ### server/index.ts
 
-`server/index.ts` is the entry-point into the server-side code of this plugin. It is identical in almost every way to the client-side entry-point:
+`server/index.ts` is the entry-point into the server-side code of this plugin.
+
+```ts
+import type { PluginInitializerContext } from '@kbn/core/server';
+
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { DemoPlugin } = await import('./plugin');
+  return new DemoPlugin(initializerContext);
+}
+```
 
 ### server/plugin.ts
 

docs/developer/architecture/core/configuration-service.asciidoc

@@ -35,7 +35,7 @@ export type MyPluginConfigType = TypeOf<typeof config.schema>;
 
 * Read config value exposed via `PluginInitializerContext`:
 
-*my_plugin/server/index.ts*
+*my_plugin/server/plugin.ts*
 [source,typescript]
 ----
 import type { PluginInitializerContext } from '@kbn/core/server';

docs/developer/architecture/kibana-platform-plugin-api.asciidoc

@@ -100,9 +100,9 @@ entry-point:
 [source,typescript]
 ----
 import type { PluginInitializerContext } from '@kbn/core/server';
-import { MyPlugin } from './plugin';
 
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { MyPlugin } = await import('./plugin');
   return new MyPlugin(initializerContext);
 }
 ----

examples/bfetch_explorer/server/index.ts

@@ -6,6 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { BfetchExplorerPlugin } from './plugin';
-
-export const plugin = () => new BfetchExplorerPlugin();
+export const plugin = async () => {
+  const { BfetchExplorerPlugin } = await import('./plugin');
+  return new BfetchExplorerPlugin();
+};

examples/content_management_examples/server/index.ts

@@ -7,8 +7,8 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { ContentManagementExamplesPlugin } from './plugin';
 
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { ContentManagementExamplesPlugin } = await import('./plugin');
   return new ContentManagementExamplesPlugin(initializerContext);
 }

examples/embeddable_examples/server/index.ts

@@ -8,6 +8,7 @@
 
 import { PluginInitializer } from '@kbn/core/server';
 
-import { EmbeddableExamplesPlugin } from './plugin';
-
-export const plugin: PluginInitializer<void, void> = () => new EmbeddableExamplesPlugin();
+export const plugin: PluginInitializer<void, void> = async () => {
+  const { EmbeddableExamplesPlugin } = await import('./plugin');
+  return new EmbeddableExamplesPlugin();
+};

examples/feature_control_examples/server/index.ts

@@ -6,6 +6,8 @@
  * Side Public License, v 1.
  */
 import { PluginInitializer } from '@kbn/core/server';
-import { FeatureControlsPluginExample } from './plugin';
 
-export const plugin: PluginInitializer<void, void> = () => new FeatureControlsPluginExample();
+export const plugin: PluginInitializer<void, void> = async () => {
+  const { FeatureControlsPluginExample } = await import('./plugin');
+  return new FeatureControlsPluginExample();
+};

examples/field_formats_example/server/index.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { FieldFormatsExamplePlugin } from './plugin';
-
-export function plugin() {
+export async function plugin() {
+  const { FieldFormatsExamplePlugin } = await import('./plugin');
   return new FieldFormatsExamplePlugin();
 }

examples/files_example/server/index.ts

@@ -7,11 +7,11 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { FilesExamplePlugin } from './plugin';
 
 //  This exports static code and TypeScript types,
 //  as well as, Kibana Platform `plugin()` initializer.
 
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { FilesExamplePlugin } = await import('./plugin');
   return new FilesExamplePlugin(initializerContext);
 }

examples/guided_onboarding_example/server/index.ts

@@ -7,6 +7,8 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { GuidedOnboardingExamplePlugin } from './plugin';
 
-export const plugin = (ctx: PluginInitializerContext) => new GuidedOnboardingExamplePlugin(ctx);
+export const plugin = async (ctx: PluginInitializerContext) => {
+  const { GuidedOnboardingExamplePlugin } = await import('./plugin');
+  return new GuidedOnboardingExamplePlugin(ctx);
+};

examples/preboot_example/server/index.ts

@@ -10,11 +10,13 @@ import type { TypeOf } from '@kbn/config-schema';
 import type { PluginConfigDescriptor, PluginInitializerContext } from '@kbn/core/server';
 
 import { ConfigSchema } from './config';
-import { PrebootExamplePlugin } from './plugin';
 
 export const config: PluginConfigDescriptor<TypeOf<typeof ConfigSchema>> = {
   schema: ConfigSchema,
   exposeToBrowser: { token: true },
 };
 
-export const plugin = (context: PluginInitializerContext) => new PrebootExamplePlugin(context);
+export const plugin = async (context: PluginInitializerContext) => {
+  const { PrebootExamplePlugin } = await import('./plugin');
+  return new PrebootExamplePlugin(context);
+};

examples/response_stream/server/index.ts

@@ -8,8 +8,7 @@
 
 import { PluginInitializerContext } from '@kbn/core/server';
 
-import { ResponseStreamPlugin } from './plugin';
-
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { ResponseStreamPlugin } = await import('./plugin');
   return new ResponseStreamPlugin(initializerContext);
 }

examples/routing_example/server/index.ts

@@ -8,6 +8,7 @@
 
 import { PluginInitializer } from '@kbn/core/server';
 
-import { RoutingExamplePlugin } from './plugin';
-
-export const plugin: PluginInitializer<{}, {}> = () => new RoutingExamplePlugin();
+export const plugin: PluginInitializer<{}, {}> = async () => {
+  const { RoutingExamplePlugin } = await import('./plugin');
+  return new RoutingExamplePlugin();
+};

examples/screenshot_mode_example/server/index.ts

@@ -7,6 +7,8 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { ScreenshotModeExamplePlugin } from './plugin';
 
-export const plugin = (ctx: PluginInitializerContext) => new ScreenshotModeExamplePlugin(ctx);
+export const plugin = async (ctx: PluginInitializerContext) => {
+  const { ScreenshotModeExamplePlugin } = await import('./plugin');
+  return new ScreenshotModeExamplePlugin(ctx);
+};

examples/search_examples/server/index.ts

@@ -7,9 +7,9 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { SearchExamplesPlugin } from './plugin';
 
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { SearchExamplesPlugin } = await import('./plugin');
   return new SearchExamplesPlugin(initializerContext);
 }
 

examples/user_profile_examples/server/index.ts

@@ -5,6 +5,8 @@
  * in compliance with, at your election, the Elastic License 2.0 or the Server
  * Side Public License, v 1.
  */
-import { UserProfilesPlugin } from './plugin';
 
-export const plugin = () => new UserProfilesPlugin();
+export const plugin = async () => {
+  const { UserProfilesPlugin } = await import('./plugin');
+  return new UserProfilesPlugin();
+};

examples/v8_profiler_examples/server/index.ts

@@ -7,8 +7,8 @@
  */
 
 import { PluginInitializerContext } from '@kbn/core/server';
-import { V8ProfilerExamplesPlugin } from './plugin';
 
-export function plugin(initializerContext: PluginInitializerContext) {
+export async function plugin(initializerContext: PluginInitializerContext) {
+  const { V8ProfilerExamplesPlugin } = await import('./plugin');
   return new V8ProfilerExamplesPlugin(initializerContext);
 }

packages/core/plugins/core-plugins-server-internal/src/plugin.test.ts

@@ -157,7 +157,7 @@ describe('`constructor` correctly sets non-external source', () => {
   });
 });
 
-test('`setup` fails if `plugin` initializer is not exported', () => {
+test('`setup` fails if the plugin has not been initialized', () => {
   const manifest = createPluginManifest();
   const opaqueId = Symbol();
   const plugin = new PluginWrapper({
@@ -176,11 +176,32 @@ test('`setup` fails if `plugin` initializer is not exported', () => {
   expect(() =>
     plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {})
   ).toThrowErrorMatchingInlineSnapshot(
+    `"The plugin is not initialized. Call the init method first."`
+  );
+});
+
+test('`init` fails if `plugin` initializer is not exported', async () => {
+  const manifest = createPluginManifest();
+  const opaqueId = Symbol();
+  const plugin = new PluginWrapper({
+    path: 'plugin-without-initializer-path',
+    manifest,
+    opaqueId,
+    initializerContext: createPluginInitializerContext({
+      coreContext,
+      opaqueId,
+      manifest,
+      instanceInfo,
+      nodeInfo,
+    }),
+  });
+
+  await expect(() => plugin.init()).rejects.toThrowErrorMatchingInlineSnapshot(
     `"Plugin \\"some-plugin-id\\" does not export \\"plugin\\" definition (plugin-without-initializer-path)."`
   );
 });
 
-test('`setup` fails if plugin initializer is not a function', () => {
+test('`init` fails if plugin initializer is not a function', async () => {
   const manifest = createPluginManifest();
   const opaqueId = Symbol();
   const plugin = new PluginWrapper({
@@ -196,14 +217,12 @@ test('`setup` fails if plugin initializer is not a function', () => {
     }),
   });
 
-  expect(() =>
-    plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {})
-  ).toThrowErrorMatchingInlineSnapshot(
+  await expect(() => plugin.init()).rejects.toThrowErrorMatchingInlineSnapshot(
     `"Definition of plugin \\"some-plugin-id\\" should be a function (plugin-with-wrong-initializer-path)."`
   );
 });
 
-test('`setup` fails if initializer does not return object', () => {
+test('`init` fails if initializer does not return object', async () => {
   const manifest = createPluginManifest();
   const opaqueId = Symbol();
   const plugin = new PluginWrapper({
@@ -219,16 +238,14 @@ test('`setup` fails if initializer does not return object', () => {
     }),
   });
 
-  mockPluginInitializer.mockReturnValue(null);
+  mockPluginInitializer.mockResolvedValue(null);
 
-  expect(() =>
-    plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {})
-  ).toThrowErrorMatchingInlineSnapshot(
+  await expect(() => plugin.init()).rejects.toThrowErrorMatchingInlineSnapshot(
     `"Initializer for plugin \\"some-plugin-id\\" is expected to return plugin instance, but returned \\"null\\"."`
   );
 });
 
-test('`setup` fails if object returned from initializer does not define `setup` function', () => {
+test('`init` fails if object returned from initializer does not define `setup` function', async () => {
   const manifest = createPluginManifest();
   const opaqueId = Symbol();
   const plugin = new PluginWrapper({
@@ -245,11 +262,9 @@ test('`setup` fails if object returned from initializer does not define `setup`
   });
 
   const mockPluginInstance = { run: jest.fn() };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
 
-  expect(() =>
-    plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {})
-  ).toThrowErrorMatchingInlineSnapshot(
+  await expect(() => plugin.init()).rejects.toThrowErrorMatchingInlineSnapshot(
     `"Instance of plugin \\"some-plugin-id\\" does not define \\"setup\\" function."`
   );
 });
@@ -272,7 +287,9 @@ test('`setup` initializes plugin and calls appropriate lifecycle hook', async ()
   });
 
   const mockPluginInstance = { setup: jest.fn().mockResolvedValue({ contract: 'yes' }) };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
+
+  await plugin.init();
 
   const setupContext = createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver });
   const setupDependencies = { 'some-required-dep': { contract: 'no' } };
@@ -323,8 +340,9 @@ test('`start` fails invoked for the `preboot` plugin', async () => {
   });
 
   const mockPluginInstance = { setup: jest.fn() };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
 
+  await plugin.init();
   await plugin.setup({} as any, {} as any);
 
   expect(() => plugin.start({} as any, {} as any)).toThrowErrorMatchingInlineSnapshot(
@@ -355,8 +373,9 @@ test('`start` calls plugin.start with context and dependencies', async () => {
     setup: jest.fn(),
     start: jest.fn().mockResolvedValue(pluginStartContract),
   };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
 
+  await plugin.init();
   await plugin.setup({} as any, {} as any);
 
   const startContract = await plugin.start(context, deps);
@@ -399,8 +418,9 @@ test("`start` resolves `startDependencies` Promise after plugin's start", async
       return pluginStartContract;
     },
   };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
 
+  await plugin.init();
   await plugin.setup({} as any, {} as any);
 
   const startDependenciesCheck = plugin.startDependencies.then((resolvedStartDeps) => {
@@ -429,7 +449,7 @@ test('`stop` fails if plugin is not set up', async () => {
   });
 
   const mockPluginInstance = { setup: jest.fn(), stop: jest.fn() };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
 
   await expect(plugin.stop()).rejects.toMatchInlineSnapshot(
     `[Error: Plugin "some-plugin-id" can't be stopped since it isn't set up.]`
@@ -453,7 +473,8 @@ test('`stop` does nothing if plugin does not define `stop` function', async () =
     }),
   });
 
-  mockPluginInitializer.mockReturnValue({ setup: jest.fn() });
+  mockPluginInitializer.mockResolvedValue({ setup: jest.fn() });
+  await plugin.init();
   await plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {});
 
   await expect(plugin.stop()).resolves.toBeUndefined();
@@ -476,7 +497,8 @@ test('`stop` calls `stop` defined by the plugin instance', async () => {
   });
 
   const mockPluginInstance = { setup: jest.fn(), stop: jest.fn() };
-  mockPluginInitializer.mockReturnValue(mockPluginInstance);
+  mockPluginInitializer.mockResolvedValue(mockPluginInstance);
+  await plugin.init();
   await plugin.setup(createPluginSetupContext({ deps: setupDeps, plugin, runtimeResolver }), {});
 
   await expect(plugin.stop()).resolves.toBeUndefined();