Max buffer size

packages/client-http/src/ApplyManager.test.ts

@@ -14,6 +14,7 @@ describe('ApplyManager', () => {
   beforeEach(() => {
     instanceUnderTest = new ApplyManager({
       timeout: 100,
+      maxBufferSize: 3,
       client: mockClient,
     });
     resolveMock.mockResolvedValue({});
@@ -99,4 +100,31 @@ describe('ApplyManager', () => {
       'some-token2',
     );
   });
+
+  it('should send apply event when the max buffer size is met, and flush the apply events', async () => {
+    const applyTime = new Date().toISOString();
+
+    instanceUnderTest.apply('some-token', 'apply-test');
+    instanceUnderTest.apply('some-token', 'apply-test1');
+    instanceUnderTest.apply('some-token', 'apply-test2');
+
+    expect(resolveMock).toHaveBeenCalledTimes(1);
+    expect(resolveMock).toHaveBeenCalledWith(
+      [
+        {
+          flag: 'flags/apply-test',
+          applyTime: applyTime,
+        },
+        {
+          flag: 'flags/apply-test1',
+          applyTime: applyTime,
+        },
+        {
+          flag: 'flags/apply-test2',
+          applyTime: applyTime,
+        },
+      ],
+      'some-token',
+    );
+  });
 });

packages/client-http/src/ApplyManager.ts

@@ -2,18 +2,21 @@ import { ConfidenceClient, AppliedFlag } from './client';
 
 export interface ApplyManagerOptions {
   timeout: number;
+  maxBufferSize: number;
   client: ConfidenceClient;
 }
 
 export class ApplyManager {
   private resolveTokenPending: Map<string, AppliedFlag[]> = new Map();
   private resolveTokenSeen: Map<string, Set<string>> = new Map();
   private readonly timeout: number;
+  private readonly maxBufferSize: number;
   private client: ConfidenceClient;
   private flushTimeout: ReturnType<typeof setTimeout> | null = null;
 
   constructor(options: ApplyManagerOptions) {
     this.timeout = options.timeout;
+    this.maxBufferSize = options.maxBufferSize;
     this.client = options.client;
   }
 
@@ -61,6 +64,11 @@ export class ApplyManager {
     if (this.flushTimeout) {
       clearTimeout(this.flushTimeout);
     }
-    this.flushTimeout = setTimeout(() => this.flush(), this.timeout);
+
+    if ((this.resolveTokenPending.get(resolveToken)?.length || 0) >= this.maxBufferSize) {
+      this.flush();
+    } else {
+      this.flushTimeout = setTimeout(() => this.flush(), this.timeout);
+    }
   }
 }

packages/openfeature-web-provider/src/ConfidenceWebProvider.ts

@@ -16,6 +16,7 @@ import equal from 'fast-deep-equal';
 import { ApplyManager, ConfidenceClient, Configuration, ResolveContext } from '@spotify-confidence/client-http';
 
 const APPLY_TIMEOUT = 250;
+const MAX_APPLY_BUFFER_SIZE = 20;
 
 export interface ConfidenceWebProviderOptions {
   apply: 'access' | 'backend';
@@ -35,7 +36,11 @@ export class ConfidenceWebProvider implements Provider {
   constructor(client: ConfidenceClient, options: ConfidenceWebProviderOptions) {
     this.client = client;
     if (options.apply !== 'backend') {
-      this.applyManager = new ApplyManager({ client: this.client, timeout: APPLY_TIMEOUT });
+      this.applyManager = new ApplyManager({
+        client: this.client,
+        timeout: APPLY_TIMEOUT,
+        maxBufferSize: MAX_APPLY_BUFFER_SIZE,
+      });
     }
   }