feat: add init/shutdown and events (#436)

Signed-off-by: Lukas Reining <[email protected]>
Co-authored-by: Michael Beemer <[email protected]>
Co-authored-by: Todd Baert <[email protected]>

Author: 3 people

jest.config.ts

@@ -108,6 +108,12 @@ export default {
   preset: 'ts-jest',
   // Run tests from one or more projects
   projects: [
+    {
+      displayName: 'shared',
+      testEnvironment: 'node',
+      preset: 'ts-jest',
+      testMatch: ['<rootDir>/packages/shared/test/**/*.spec.ts'],
+    },
     {
       displayName: 'server',
       testEnvironment: 'node',
@@ -137,7 +143,7 @@ export default {
       setupFiles: ['<rootDir>/packages/client/e2e/step-definitions/setup.ts'],
       moduleNameMapper: {
         '^uuid$': require.resolve('uuid'),
-        '^(.*)\\.js$': ['$1', '$1.js']
+        '^(.*)\\.js$': ['$1', '$1.js'],
       },
     },
   ],

package.json

@@ -72,8 +72,5 @@
     "packages/server",
     "packages/client",
     "packages/shared"
-  ],
-  "dependencies": {
-
-  }
+  ]
 }

packages/client/e2e/step-definitions/evaluation.spec.ts

@@ -23,15 +23,15 @@ const givenAnOpenfeatureClientIsRegisteredWithCacheDisabled = (
 
 defineFeature(feature, (test) => {
   beforeAll((done) => {
-    client.addHandler(ProviderEvents.Ready, () => {
+    client.addHandler(ProviderEvents.Ready, async () => {
       setTimeout(() => {
         done(); // TODO remove this once flagd provider properly implements readiness (for now, we add a 2s wait).
       }, 2000);
     });
   });
 
-  afterAll(() => {
-    OpenFeature.close();
+  afterAll(async () => {
+    await OpenFeature.close();
   });
 
   test('Resolves boolean value', ({ given, when, then }) => {

packages/client/src/client.ts

@@ -3,27 +3,22 @@ import {
   ErrorCode,
   EvaluationContext,
   EvaluationDetails,
+  EventHandler,
   FlagValue,
   FlagValueType,
   HookContext,
   JsonValue,
   Logger,
   OpenFeatureError,
+  OpenFeatureEventEmitter,
+  ProviderEvents,
   ProviderStatus,
   ResolutionDetails,
   SafeLogger,
   StandardResolutionReasons,
 } from '@openfeature/shared';
 import { OpenFeature } from './open-feature';
-import {
-  Client,
-  FlagEvaluationOptions,
-  Handler,
-  Hook,
-  OpenFeatureEventEmitter,
-  Provider,
-  ProviderEvents,
-} from './types';
+import { Client, FlagEvaluationOptions, Hook, Provider } from './types';
 
 type OpenFeatureClientOptions = {
   name?: string;
@@ -51,16 +46,24 @@ export class OpenFeatureClient implements Client {
     };
   }
 
-  addHandler(eventType: ProviderEvents, handler: Handler): void {
-    this.events().on(eventType, handler);
+  addHandler(eventType: ProviderEvents, handler: EventHandler): void {
+    this.events().addHandler(eventType, handler);
     const providerReady = !this._provider.status || this._provider.status === ProviderStatus.READY;
 
     if (eventType === ProviderEvents.Ready && providerReady) {
       // run immediately, we're ready.
-      handler();
+      handler({ clientName: this.metadata.name });
     }
   }
 
+  removeHandler(notificationType: ProviderEvents, handler: EventHandler) {
+    this.events().removeHandler(notificationType, handler);
+  }
+
+  getHandlers(eventType: ProviderEvents) {
+    return this.events().getHandlers(eventType);
+  }
+
   setLogger(logger: Logger): OpenFeatureClient {
     this._clientLogger = new SafeLogger(logger);
     return this;

packages/client/src/open-feature.ts

@@ -1,15 +1,7 @@
-import {
-  EvaluationContext,
-  FlagValue,
-  Logger,
-  OpenFeatureCommonAPI,
-  ProviderMetadata,
-  SafeLogger,
-} from '@openfeature/shared';
+import { EvaluationContext, FlagValue, Logger, OpenFeatureCommonAPI, SafeLogger } from '@openfeature/shared';
 import { OpenFeatureClient } from './client';
 import { NOOP_PROVIDER } from './no-op-provider';
-import { Client, Hook, OpenFeatureEventEmitter, Provider, ProviderEvents } from './types';
-import { objectOrUndefined, stringOrUndefined } from '@openfeature/shared/src/type-guards';
+import { Client, Hook, Provider } from './types';
 
 // use a symbol as a key for the global singleton
 const GLOBAL_OPENFEATURE_API_KEY = Symbol.for('@openfeature/js.api');
@@ -19,12 +11,9 @@ type OpenFeatureGlobal = {
 };
 const _globalThis = globalThis as OpenFeatureGlobal;
 
-export class OpenFeatureAPI extends OpenFeatureCommonAPI {
+export class OpenFeatureAPI extends OpenFeatureCommonAPI<Provider> {
   protected _hooks: Hook[] = [];
-  private readonly _events = new OpenFeatureEventEmitter();
   protected _defaultProvider: Provider = NOOP_PROVIDER;
-  protected _clientProviders: Map<string, Provider> = new Map();
-  protected _clientEvents: Map<string | undefined, OpenFeatureEventEmitter> = new Map();
 
   // eslint-disable-next-line @typescript-eslint/no-empty-function
   private constructor() {
@@ -47,14 +36,6 @@ export class OpenFeatureAPI extends OpenFeatureCommonAPI {
     return instance;
   }
 
-  /**
-   * Get metadata about registered provider.
-   * @returns {ProviderMetadata} Provider Metadata
-   */
-  get providerMetadata(): ProviderMetadata {
-    return this._defaultProvider.metadata;
-  }
-
   setLogger(logger: Logger): this {
     this._logger = new SafeLogger(logger);
     return this;
@@ -80,70 +61,6 @@ export class OpenFeatureAPI extends OpenFeatureCommonAPI {
     await this._defaultProvider?.onContextChange?.(oldContext, context);
   }
 
-  /**
-   * Sets the default provider for flag evaluations.
-   * This provider will be used by unnamed clients and named clients to which no provider is bound.
-   * Setting a provider supersedes the current provider used in new and existing clients without a name.
-   * @param {Provider} provider The provider responsible for flag evaluations.
-   * @returns {OpenFeatureAPI} OpenFeature API
-   */
-  setProvider(provider: Provider): this;
-  /**
-   * Sets the provider that OpenFeature will use for flag evaluations of providers with the given name.
-   * Setting a provider supersedes the current provider used in new and existing clients with that name.
-   * @param {string} clientName The name to identify the client
-   * @param {Provider} provider The provider responsible for flag evaluations.
-   * @returns {OpenFeatureAPI} OpenFeature API
-   */
-  setProvider(clientName: string, provider: Provider): this;
-  setProvider(clientOrProvider?: string | Provider, providerOrUndefined?: Provider): this {
-    const clientName = stringOrUndefined(clientOrProvider);
-    const provider = objectOrUndefined<Provider>(clientOrProvider) ?? objectOrUndefined<Provider>(providerOrUndefined);
-
-    if (!provider) {
-      return this;
-    }
-
-    const oldProvider = this.getProviderForClient(clientName);
-
-    // ignore no-ops
-    if (oldProvider === provider) {
-      return this;
-    }
-
-    if (clientName) {
-      this._clientProviders.set(clientName, provider);
-    } else {
-      this._defaultProvider = provider;
-    }
-
-    const clientEmitter = this.getEventEmitterForClient(clientName);
-    this.transferListeners(oldProvider, provider, clientEmitter);
-
-    if (typeof provider.initialize === 'function') {
-      provider
-        .initialize?.(this._context)
-        ?.then(() => {
-          clientEmitter.emit(ProviderEvents.Ready);
-          this._events?.emit(ProviderEvents.Ready);
-        })
-        ?.catch(() => {
-          clientEmitter.emit(ProviderEvents.Error);
-          this._events?.emit(ProviderEvents.Error);
-        });
-    } else {
-      clientEmitter.emit(ProviderEvents.Ready);
-      this._events?.emit(ProviderEvents.Ready);
-    }
-
-    oldProvider?.onClose?.();
-    return this;
-  }
-
-  async close(): Promise<void> {
-    await this?._defaultProvider?.onClose?.();
-  }
-
   /**
    * A factory function for creating new named OpenFeature clients. Clients can contain
    * their own state (e.g. logger, hook, context). Multiple clients can be used
@@ -165,39 +82,6 @@ export class OpenFeatureAPI extends OpenFeatureCommonAPI {
       { name, version }
     );
   }
-
-  private getProviderForClient(name?: string): Provider {
-    if (!name) {
-      return this._defaultProvider;
-    }
-
-    return this._clientProviders.get(name) ?? this._defaultProvider;
-  }
-
-  private getEventEmitterForClient(name?: string): OpenFeatureEventEmitter {
-    const emitter = this._clientEvents.get(name);
-
-    if (emitter) {
-      return emitter;
-    }
-
-    const newEmitter = new OpenFeatureEventEmitter({});
-    this._clientEvents.set(name, newEmitter);
-    return newEmitter;
-  }
-
-  private transferListeners(oldProvider: Provider, newProvider: Provider, clientEmitter: OpenFeatureEventEmitter) {
-    oldProvider.events?.removeAllListeners();
-
-    // iterate over the event types
-    Object.values(ProviderEvents).forEach((eventType) =>
-      newProvider.events?.on(eventType, () => {
-        // on each event type, fire the associated handlers
-        clientEmitter.emit(eventType);
-        this._events.emit(eventType);
-      })
-    );
-  }
 }
 
 /**

packages/client/src/types.ts

@@ -4,6 +4,7 @@ import {
   CommonProvider,
   EvaluationContext,
   EvaluationDetails,
+  Eventing,
   FlagValue,
   HookContext,
   HookHints,
@@ -15,48 +16,6 @@ import {
   ProviderMetadata,
   ResolutionDetails,
 } from '@openfeature/shared';
-import { EventEmitter as OpenFeatureEventEmitter } from 'events';
-export { OpenFeatureEventEmitter };
-
-export enum ProviderEvents {
-  /**
-   * The provider is ready to evaluate flags.
-   */
-  Ready = 'PROVIDER_READY',
-
-  /**
-   * The provider is in an error state.
-   */
-  Error = 'PROVIDER_ERROR',
-
-  /**
-   * The flag configuration in the source-of-truth has changed.
-   */
-  ConfigurationChanged = 'PROVIDER_CONFIGURATION_CHANGED',
-
-  /**
-   * The provider's cached state is not longer valid and may not be up-to-date with the source of truth.
-   */
-  Stale = 'PROVIDER_STALE',
-}
-
-export interface EventData {
-  flagKeysChanged?: string[];
-  changeMetadata?: { [key: string]: boolean | string }; // similar to flag metadata
-}
-
-export interface Eventing {
-  addHandler(notificationType: string, handler: Handler): void;
-}
-
-export type EventContext = {
-  notificationType: string;
-  [key: string]: unknown;
-};
-
-export type Handler = (eventContext?: EventContext) => void;
-
-export type EventCallbackMessage = (eventContext: EventContext) => void;
 
 /**
  * Interface that providers must implement to resolve flag values for their particular
@@ -73,12 +32,6 @@ export interface Provider extends CommonProvider {
    */
   readonly hooks?: Hook[];
 
-  /**
-   * An event emitter for ProviderEvents.
-   * @see ProviderEvents
-   */
-  events?: OpenFeatureEventEmitter;
-
   /**
    * A handler function to reconcile changes when the static context.
    * Called by the SDK when the context is changed.
@@ -87,20 +40,6 @@ export interface Provider extends CommonProvider {
    */
   onContextChange?(oldContext: EvaluationContext, newContext: EvaluationContext): Promise<void>;
 
-  // TODO: move to common Provider type when we want close in server
-  onClose?(): Promise<void>;
-
-  // TODO: move to common Provider type when we want close in server
-  /**
-   * A handler function used to setup the provider.
-   * Called by the SDK after the provider is set.
-   * When the returned promise resolves, the SDK fires the ProviderEvents.Ready event.
-   * If the returned promise rejects, the SDK fires the ProviderEvents.Error event.
-   * Use this function to perform any context-dependent setup within the provider.
-   * @param context
-   */
-  initialize?(context: EvaluationContext): Promise<void>;
-
   /**
    * Resolve a boolean flag and its evaluation details.
    */