Expose whitelisted config values to client-side plugin (elastic#50641)

* introduce PluginConfigDescriptor type

* inject client plugin configs in injectedMetadata

* expose client config in PluginInitializerContext

* add example implementation in testbed

* update generated doc

* only generates ui config entry for plugins exposing properties to client

* separate plugin configs from plugins

* restructure plugin services tests

* fix test/mocks due to plugin configs api changes

* add unit tests

* update migration guide

* update tsdoc

* fix typecheck

* use sync getter for config on client side instead of observable

* change type of exposeToBrowser prop

* updates generated doc

* fix doc and address nits

docs/development/core/public/kibana-plugin-public.plugininitializercontext.config.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-public](./kibana-plugin-public.md) &gt; [PluginInitializerContext](./kibana-plugin-public.plugininitializercontext.md) &gt; [config](./kibana-plugin-public.plugininitializercontext.config.md)
+
+## PluginInitializerContext.config property
+
+<b>Signature:</b>
+
+```typescript
+readonly config: {
+        get: <T extends object = ConfigSchema>() => T;
+    };
+```

docs/development/core/public/kibana-plugin-public.plugininitializercontext.md

@@ -9,13 +9,14 @@ The available core services passed to a `PluginInitializer`
 <b>Signature:</b>
 
 ```typescript
-export interface PluginInitializerContext 
+export interface PluginInitializerContext<ConfigSchema extends object = object> 
 ```
 
 ## Properties
 
 |  Property | Type | Description |
 |  --- | --- | --- |
+|  [config](./kibana-plugin-public.plugininitializercontext.config.md) | <code>{</code><br/><code>        get: &lt;T extends object = ConfigSchema&gt;() =&gt; T;</code><br/><code>    }</code> |  |
 |  [env](./kibana-plugin-public.plugininitializercontext.env.md) | <code>{</code><br/><code>        mode: Readonly&lt;EnvironmentMode&gt;;</code><br/><code>        packageInfo: Readonly&lt;PackageInfo&gt;;</code><br/><code>    }</code> |  |
 |  [opaqueId](./kibana-plugin-public.plugininitializercontext.opaqueid.md) | <code>PluginOpaqueId</code> | A symbol used to identify this plugin in the system. Needed when registering handlers or context providers. |
 

docs/development/core/server/kibana-plugin-server.md

@@ -75,6 +75,7 @@ The plugin integrates with the core system via lifecycle events: `setup`<!-- -->
 |  [OnPreAuthToolkit](./kibana-plugin-server.onpreauthtoolkit.md) | A tool set defining an outcome of OnPreAuth interceptor for incoming request. |
 |  [PackageInfo](./kibana-plugin-server.packageinfo.md) |  |
 |  [Plugin](./kibana-plugin-server.plugin.md) | The interface that should be returned by a <code>PluginInitializer</code>. |
+|  [PluginConfigDescriptor](./kibana-plugin-server.pluginconfigdescriptor.md) | Describes a plugin configuration schema and capabilities. |
 |  [PluginInitializerContext](./kibana-plugin-server.plugininitializercontext.md) | Context that's available to plugins during initialization stage. |
 |  [PluginManifest](./kibana-plugin-server.pluginmanifest.md) | Describes the set of required and optional properties plugin can define in its mandatory JSON manifest file. |
 |  [PluginsServiceSetup](./kibana-plugin-server.pluginsservicesetup.md) |  |
@@ -156,6 +157,7 @@ The plugin integrates with the core system via lifecycle events: `setup`<!-- -->
 |  [MutatingOperationRefreshSetting](./kibana-plugin-server.mutatingoperationrefreshsetting.md) | Elasticsearch Refresh setting for mutating operation |
 |  [OnPostAuthHandler](./kibana-plugin-server.onpostauthhandler.md) | See [OnPostAuthToolkit](./kibana-plugin-server.onpostauthtoolkit.md)<!-- -->. |
 |  [OnPreAuthHandler](./kibana-plugin-server.onpreauthhandler.md) | See [OnPreAuthToolkit](./kibana-plugin-server.onpreauthtoolkit.md)<!-- -->. |
+|  [PluginConfigSchema](./kibana-plugin-server.pluginconfigschema.md) | Dedicated type for plugin configuration schema. |
 |  [PluginInitializer](./kibana-plugin-server.plugininitializer.md) | The <code>plugin</code> export at the root of a plugin's <code>server</code> directory should conform to this interface. |
 |  [PluginName](./kibana-plugin-server.pluginname.md) | Dedicated type for plugin name/id that is supposed to make Map/Set/Arrays that use it as a key or value more obvious. |
 |  [PluginOpaqueId](./kibana-plugin-server.pluginopaqueid.md) |  |

docs/development/core/server/kibana-plugin-server.pluginconfigdescriptor.exposetobrowser.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [PluginConfigDescriptor](./kibana-plugin-server.pluginconfigdescriptor.md) &gt; [exposeToBrowser](./kibana-plugin-server.pluginconfigdescriptor.exposetobrowser.md)
+
+## PluginConfigDescriptor.exposeToBrowser property
+
+List of configuration properties that will be available on the client-side plugin.
+
+<b>Signature:</b>
+
+```typescript
+exposeToBrowser?: {
+        [P in keyof T]?: boolean;
+    };
+```

docs/development/core/server/kibana-plugin-server.pluginconfigdescriptor.md

@@ -0,0 +1,45 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [PluginConfigDescriptor](./kibana-plugin-server.pluginconfigdescriptor.md)
+
+## PluginConfigDescriptor interface
+
+Describes a plugin configuration schema and capabilities.
+
+<b>Signature:</b>
+
+```typescript
+export interface PluginConfigDescriptor<T = any> 
+```
+
+## Properties
+
+|  Property | Type | Description |
+|  --- | --- | --- |
+|  [exposeToBrowser](./kibana-plugin-server.pluginconfigdescriptor.exposetobrowser.md) | <code>{</code><br/><code>        [P in keyof T]?: boolean;</code><br/><code>    }</code> | List of configuration properties that will be available on the client-side plugin. |
+|  [schema](./kibana-plugin-server.pluginconfigdescriptor.schema.md) | <code>PluginConfigSchema&lt;T&gt;</code> | Schema to use to validate the plugin configuration.[PluginConfigSchema](./kibana-plugin-server.pluginconfigschema.md) |
+
+## Example
+
+
+```typescript
+// my_plugin/server/index.ts
+import { schema, TypeOf } from '@kbn/config-schema';
+import { PluginConfigDescriptor } from 'kibana/server';
+
+const configSchema = schema.object({
+  secret: schema.string({ defaultValue: 'Only on server' }),
+  uiProp: schema.string({ defaultValue: 'Accessible from client' }),
+});
+
+type ConfigType = TypeOf<typeof configSchema>;
+
+export const config: PluginConfigDescriptor<ConfigType> = {
+  exposeToBrowser: {
+    uiProp: true,
+  },
+  schema: configSchema,
+};
+
+```
+

docs/development/core/server/kibana-plugin-server.pluginconfigdescriptor.schema.md

@@ -0,0 +1,15 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [PluginConfigDescriptor](./kibana-plugin-server.pluginconfigdescriptor.md) &gt; [schema](./kibana-plugin-server.pluginconfigdescriptor.schema.md)
+
+## PluginConfigDescriptor.schema property
+
+Schema to use to validate the plugin configuration.
+
+[PluginConfigSchema](./kibana-plugin-server.pluginconfigschema.md)
+
+<b>Signature:</b>
+
+```typescript
+schema: PluginConfigSchema<T>;
+```

docs/development/core/server/kibana-plugin-server.pluginconfigschema.md

@@ -0,0 +1,13 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [PluginConfigSchema](./kibana-plugin-server.pluginconfigschema.md)
+
+## PluginConfigSchema type
+
+Dedicated type for plugin configuration schema.
+
+<b>Signature:</b>
+
+```typescript
+export declare type PluginConfigSchema<T> = Type<T>;
+```

docs/development/core/server/kibana-plugin-server.pluginsservicesetup.md

@@ -16,5 +16,6 @@ export interface PluginsServiceSetup
 |  Property | Type | Description |
 |  --- | --- | --- |
 |  [contracts](./kibana-plugin-server.pluginsservicesetup.contracts.md) | <code>Map&lt;PluginName, unknown&gt;</code> |  |
+|  [uiPluginConfigs](./kibana-plugin-server.pluginsservicesetup.uipluginconfigs.md) | <code>Map&lt;PluginName, Observable&lt;unknown&gt;&gt;</code> |  |
 |  [uiPlugins](./kibana-plugin-server.pluginsservicesetup.uiplugins.md) | <code>{</code><br/><code>        public: Map&lt;PluginName, DiscoveredPlugin&gt;;</code><br/><code>        internal: Map&lt;PluginName, DiscoveredPluginInternal&gt;;</code><br/><code>    }</code> |  |
 

docs/development/core/server/kibana-plugin-server.pluginsservicesetup.uipluginconfigs.md

@@ -0,0 +1,11 @@
+<!-- Do not edit this file. It is automatically generated by API Documenter. -->
+
+[Home](./index.md) &gt; [kibana-plugin-server](./kibana-plugin-server.md) &gt; [PluginsServiceSetup](./kibana-plugin-server.pluginsservicesetup.md) &gt; [uiPluginConfigs](./kibana-plugin-server.pluginsservicesetup.uipluginconfigs.md)
+
+## PluginsServiceSetup.uiPluginConfigs property
+
+<b>Signature:</b>
+
+```typescript
+uiPluginConfigs: Map<PluginName, Observable<unknown>>;
+```

src/core/public/injected_metadata/index.ts

@@ -22,5 +22,6 @@ export {
   InjectedMetadataParams,
   InjectedMetadataSetup,
   InjectedMetadataStart,
+  InjectedPluginMetadata,
   LegacyNavLink,
 } from './injected_metadata_service';

src/core/public/injected_metadata/injected_metadata_service.test.ts

@@ -69,15 +69,15 @@ describe('setup.getPlugins()', () => {
     const injectedMetadata = new InjectedMetadataService({
       injectedMetadata: {
         uiPlugins: [
-          { id: 'plugin-1', plugin: {} },
+          { id: 'plugin-1', plugin: {}, config: { clientProp: 'clientValue' } },
           { id: 'plugin-2', plugin: {} },
         ],
       },
     } as any);
 
     const plugins = injectedMetadata.setup().getPlugins();
     expect(plugins).toEqual([
-      { id: 'plugin-1', plugin: {} },
+      { id: 'plugin-1', plugin: {}, config: { clientProp: 'clientValue' } },
       { id: 'plugin-2', plugin: {} },
     ]);
   });

src/core/public/injected_metadata/injected_metadata_service.ts

@@ -38,6 +38,14 @@ export interface LegacyNavLink {
   euiIconType?: string;
 }
 
+export interface InjectedPluginMetadata {
+  id: PluginName;
+  plugin: DiscoveredPlugin;
+  config?: {
+    [key: string]: unknown;
+  };
+}
+
 /** @internal */
 export interface InjectedMetadataParams {
   injectedMetadata: {
@@ -55,10 +63,7 @@ export interface InjectedMetadataParams {
       mode: Readonly<EnvironmentMode>;
       packageInfo: Readonly<PackageInfo>;
     };
-    uiPlugins: Array<{
-      id: PluginName;
-      plugin: DiscoveredPlugin;
-    }>;
+    uiPlugins: InjectedPluginMetadata[];
     capabilities: Capabilities;
     legacyMode: boolean;
     legacyMetadata: {
@@ -165,10 +170,7 @@ export interface InjectedMetadataSetup {
   /**
    * An array of frontend plugins in topological order.
    */
-  getPlugins: () => Array<{
-    id: string;
-    plugin: DiscoveredPlugin;
-  }>;
+  getPlugins: () => InjectedPluginMetadata[];
   /** Indicates whether or not we are rendering a known legacy app. */
   getLegacyMode: () => boolean;
   getLegacyMetadata: () => {

src/core/public/mocks.ts

@@ -92,6 +92,9 @@ function pluginInitializerContextMock() {
         dist: false,
       },
     },
+    config: {
+      get: <T>() => ({} as T),
+    },
   };
 
   return mock;

src/core/public/plugins/plugin_context.ts

@@ -18,7 +18,6 @@
  */
 
 import { omit } from 'lodash';
-
 import { DiscoveredPlugin } from '../../server';
 import { PluginOpaqueId, PackageInfo, EnvironmentMode } from '../../server/types';
 import { CoreContext } from '../core_system';
@@ -31,7 +30,7 @@ import { CoreSetup, CoreStart } from '../';
  *
  * @public
  */
-export interface PluginInitializerContext {
+export interface PluginInitializerContext<ConfigSchema extends object = object> {
   /**
    * A symbol used to identify this plugin in the system. Needed when registering handlers or context providers.
    */
@@ -40,24 +39,37 @@ export interface PluginInitializerContext {
     mode: Readonly<EnvironmentMode>;
     packageInfo: Readonly<PackageInfo>;
   };
+  readonly config: {
+    get: <T extends object = ConfigSchema>() => T;
+  };
 }
 
 /**
  * Provides a plugin-specific context passed to the plugin's construtor. This is currently
  * empty but should provide static services in the future, such as config and logging.
  *
  * @param coreContext
- * @param pluginManinfest
+ * @param opaqueId
+ * @param pluginManifest
+ * @param pluginConfig
  * @internal
  */
 export function createPluginInitializerContext(
   coreContext: CoreContext,
   opaqueId: PluginOpaqueId,
-  pluginManifest: DiscoveredPlugin
+  pluginManifest: DiscoveredPlugin,
+  pluginConfig: {
+    [key: string]: unknown;
+  }
 ): PluginInitializerContext {
   return {
     opaqueId,
     env: coreContext.env,
+    config: {
+      get<T>() {
+        return (pluginConfig as unknown) as T;
+      },
+    },
   };
 }