fix: only emit resolve helper log once per flag+context

Author: nicklasl

api/sdk.api.md

@@ -13,6 +13,8 @@ export interface CacheOptions {
     //
     // @internal (undocumented)
     entries?: AsyncIterable<CacheEntry>;
+    // @internal
+    loggedFlags?: Set<string>;
     scope?: CacheScope;
 }
 

packages/sdk/src/Confidence.test.ts

@@ -21,17 +21,28 @@ describe('Confidence', () => {
     variant: 'mockVariant',
   };
 
+  const loggerSpy = {
+    infoLogs: [] as string[],
+    info: (input: string) => {
+      loggerSpy.infoLogs.push(input);
+    },
+  };
+
   beforeEach(() => {
+    loggerSpy.infoLogs = [];
     confidence = new Confidence({
       clientSecret: 'secret',
       timeout: 10,
       environment: 'client',
-      logger: {},
+      logger: loggerSpy,
       eventSenderEngine: eventSenderEngineMock,
       flagResolverClient: flagResolverClientMock,
       cacheProvider: () => {
         throw new Error('Not implemented');
       },
+      cache: {
+        loggedFlags: new Set(),
+      },
     });
     flagResolverClientMock.resolve.mockImplementation((context, _flags) => {
       const flagResolution = new Promise<FlagResolution>(resolve => {
@@ -377,5 +388,32 @@ describe('Confidence', () => {
         variant: 'mockVariant',
       });
     });
+
+    it('should log the flag resolve hint once per and context and flag', async () => {
+      const ctx = { targeting_key: 'default', pantsOn: true, pantsColor: 'blue' };
+      const c = confidence.withContext(ctx);
+      await c.evaluateFlag('flag1', 'default');
+      c.getFlag('flag1', 'default');
+
+      expect(loggerSpy.infoLogs.length).toEqual(1);
+      expect(loggerSpy.infoLogs[0]).toEqual(
+        "See resolves for 'flag1' in Confidence: https://app.confidence.spotify.com/flags/resolver-test?client-key=secret&flag=flags/flag1&context=%7B%22targeting_key%22%3A%22default%22%2C%22pantsOn%22%3Atrue%2C%22pantsColor%22%3A%22blue%22%7D",
+      );
+      c.getFlag('flag1', 'default');
+      expect(loggerSpy.infoLogs.length).toEqual(1);
+
+      await c.evaluateFlag('flag2', 'default');
+      expect(loggerSpy.infoLogs.length).toEqual(2);
+      expect(loggerSpy.infoLogs[1]).toEqual(
+        "See resolves for 'flag2' in Confidence: https://app.confidence.spotify.com/flags/resolver-test?client-key=secret&flag=flags/flag2&context=%7B%22targeting_key%22%3A%22default%22%2C%22pantsOn%22%3Atrue%2C%22pantsColor%22%3A%22blue%22%7D",
+      );
+      const c2 = c.withContext({ pantsOn: false });
+      await c2.evaluateFlag('flag2', 'default');
+      c2.getFlag('flag2', 'default');
+      expect(loggerSpy.infoLogs.length).toEqual(3);
+      expect(loggerSpy.infoLogs[2]).toEqual(
+        "See resolves for 'flag2' in Confidence: https://app.confidence.spotify.com/flags/resolver-test?client-key=secret&flag=flags/flag2&context=%7B%22targeting_key%22%3A%22default%22%2C%22pantsColor%22%3A%22blue%22%2C%22pantsOn%22%3Afalse%7D",
+      );
+    });
   });
 });

packages/sdk/src/Confidence.ts

@@ -329,11 +329,15 @@ export class Confidence implements EventSender, Trackable, FlagResolver {
   }
 
   private showLoggerLink(flag: string, context: Context) {
-    this.config.logger.info?.(
-      `See resolves for '${flag}' in Confidence: https://app.confidence.spotify.com/flags/resolver-test?client-key=${
-        this.config.clientSecret
-      }&flag=flags/${flag}&context=${encodeURIComponent(JSON.stringify(context))}`,
-    );
+    const logKey = `${flag}:${Value.serialize(context)}`;
+    if (!this.config.cache?.loggedFlags?.has(logKey)) {
+      this.config.cache?.loggedFlags?.add(logKey);
+      this.config.logger.info?.(
+        `See resolves for '${flag}' in Confidence: https://app.confidence.spotify.com/flags/resolver-test?client-key=${
+          this.config.clientSecret
+        }&flag=flags/${flag}&context=${encodeURIComponent(JSON.stringify(context))}`,
+      );
+    }
   }
 
   toOptions(): ConfidenceOptions {
@@ -371,7 +375,9 @@ export class Confidence implements EventSender, Trackable, FlagResolver {
       disableTelemetry = false,
       applyDebounce = 10,
       waitUntil,
-      cache = {},
+      cache = {
+        loggedFlags: new Set(),
+      },
     } = options;
     if (environment !== 'client' && environment !== 'backend') {
       throw new Error(`Invalid environment: ${environment}. Must be 'client' or 'backend'.`);

packages/sdk/src/flag-cache.ts

@@ -36,8 +36,26 @@ export interface CacheOptions {
   scope?: CacheScope;
   /** @internal */
   entries?: AsyncIterable<CacheEntry>;
+  /**
+   * Flags that have been logged using the showLoggerLink method.
+   * @internal
+   */
+  loggedFlags?: Set<string>;
 }
+
+type FlagCacheOptions = {
+  loggedFlags?: Set<string>;
+};
 export class FlagCache extends AbstractCache<Context, ResolveFlagsResponse, Uint8Array> {
+  /**
+   * Flags that have been logged using the showLoggerLink method.
+   * @internal
+   */
+  private readonly logs: Set<string>;
+  constructor(options: FlagCacheOptions) {
+    super();
+    this.logs = options.loggedFlags ?? new Set();
+  }
   protected serialize(value: ResolveFlagsResponse): Uint8Array {
     return ResolveFlagsResponse.encode(value).finish();
   }
@@ -62,6 +80,7 @@ export class FlagCache extends AbstractCache<Context, ResolveFlagsResponse, Uint
   toOptions(): CacheOptions {
     return {
       entries: this,
+      loggedFlags: this.logs,
     };
   }
 }
@@ -85,8 +104,11 @@ export namespace FlagCache {
     return typeof window === 'undefined' ? noScope : singletonScope;
   }
 
-  export function provider(clientKey: string, { scope = defaultScope(), entries }: CacheOptions): CacheProvider {
-    const provider = scope(() => new FlagCache());
+  export function provider(
+    clientKey: string,
+    { scope = defaultScope(), entries, loggedFlags }: CacheOptions,
+  ): CacheProvider {
+    const provider = scope(() => new FlagCache({ loggedFlags }));
     if (entries) {
       provider(clientKey).load(entries);
     }