Add layer overrides (#211)

statsig-io · Nov 28, 2022 · 673a917 · 673a917
1 parent a824223
commit 673a917
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Showing 4 changed files with 143 additions and 47 deletions.
diff --git a/src/Evaluator.ts b/src/Evaluator.ts
@@ -37,6 +37,10 @@ export default class Evaluator {
     string,
     Record<string, Record<string, unknown>>
   >;
+  private layerOverrides: Record<
+    string,
+    Record<string, Record<string, unknown>>
+  >;
   private initialized: boolean = false;
 
   private store: SpecStore;
@@ -45,6 +49,7 @@ export default class Evaluator {
     this.store = new SpecStore(fetcher, options);
     this.gateOverrides = {};
     this.configOverrides = {};
+    this.layerOverrides = {};
   }
 
   public async init(): Promise<void> {
@@ -77,53 +82,14 @@ export default class Evaluator {
     this.configOverrides[configName] = overrides;
   }
 
-  public lookupGateOverride(
-    user: StatsigUser,
-    gateName: string,
-  ): ConfigEvaluation | null {
-    const overrides = this.gateOverrides[gateName];
-    if (overrides == null) {
-      return null;
-    }
-    if (user.userID != null) {
-      // check for a user level override
-      const userOverride = overrides[user.userID];
-      if (userOverride != null) {
-        return new ConfigEvaluation(userOverride, 'override');
-      }
-    }
-
-    // check if there is a global override
-    const allOverride = overrides[''];
-    if (allOverride != null) {
-      return new ConfigEvaluation(allOverride, 'override');
-    }
-    return null;
-  }
-
-  public lookupConfigOverride(
-    user: StatsigUser,
-    configName: string,
-  ): ConfigEvaluation | null {
-    const overrides = this.configOverrides[configName];
-    if (overrides == null) {
-      return null;
-    }
-
-    if (user.userID != null) {
-      // check for a user level override
-      const userOverride = overrides[user.userID];
-      if (userOverride != null) {
-        return new ConfigEvaluation(true, 'override', [], userOverride);
-      }
-    }
-
-    // check if there is a global override
-    const allOverride = overrides[''];
-    if (allOverride != null) {
-      return new ConfigEvaluation(true, 'override', [], allOverride);
-    }
-    return null;
+  public overrideLayer(
+    layerName: string,
+    value: Record<string, unknown>,
+    userID: string | null = '',
+  ): void {
+    let overrides = this.layerOverrides[layerName] ?? {};
+    overrides[userID == null ? '' : userID] = value;
+    this.layerOverrides[layerName] = overrides;
   }
 
   public checkGate(user: StatsigUser, gateName: string): ConfigEvaluation {
@@ -161,6 +127,13 @@ export default class Evaluator {
   }
 
   public getLayer(user: StatsigUser, layerName: string): ConfigEvaluation {
+    const override = this.lookupLayerOverride(user, layerName);
+    if (override) {
+      return override.withEvaluationDetails(
+        EvaluationDetails.make(this.store, 'LocalOverride'),
+      );
+    }
+
     if (this.store.getInitReason() === 'Uninitialized') {
       return new ConfigEvaluation(false).withEvaluationDetails(
         EvaluationDetails.uninitialized(),
@@ -283,6 +256,70 @@ export default class Evaluator {
     return this.store.resetSyncTimerIfExited();
   }
 
+  private lookupGateOverride(
+    user: StatsigUser,
+    gateName: string,
+  ): ConfigEvaluation | null {
+    const overrides = this.gateOverrides[gateName];
+    if (overrides == null) {
+      return null;
+    }
+    if (user.userID != null) {
+      // check for a user level override
+      const userOverride = overrides[user.userID];
+      if (userOverride != null) {
+        return new ConfigEvaluation(userOverride, 'override');
+      }
+    }
+
+    // check if there is a global override
+    const allOverride = overrides[''];
+    if (allOverride != null) {
+      return new ConfigEvaluation(allOverride, 'override');
+    }
+    return null;
+  }
+
+  private lookupConfigOverride(
+    user: StatsigUser,
+    configName: string,
+  ): ConfigEvaluation | null {
+    const overrides = this.configOverrides[configName];
+    return this.lookupConfigBasedOverride(user, overrides);
+  }
+
+  private lookupLayerOverride(
+    user: StatsigUser,
+    layerName: string,
+  ): ConfigEvaluation | null {
+    const overrides = this.layerOverrides[layerName];
+    return this.lookupConfigBasedOverride(user, overrides);
+  }
+
+  private lookupConfigBasedOverride(
+    user: StatsigUser,
+    overrides: Record<string, Record<string, unknown>>,
+  ): ConfigEvaluation | null {
+    if (overrides == null) {
+      return null;
+    }
+
+    if (user.userID != null) {
+      // check for a user level override
+      const userOverride = overrides[user.userID];
+      if (userOverride != null) {
+        return new ConfigEvaluation(true, 'override', [], userOverride);
+      }
+    }
+
+    // check if there is a global override
+    const allOverride = overrides[''];
+    if (allOverride != null) {
+      return new ConfigEvaluation(true, 'override', [], allOverride);
+    }
+    return null;
+  }
+
   private _specToInitializeResponse(
     spec: ConfigSpec,
     res: ConfigEvaluation,

diff --git a/src/StatsigServer.ts b/src/StatsigServer.ts
@@ -453,6 +453,22 @@ export default class StatsigServer {
     });
   }
 
+  public overrideLayer(
+    layerName: string,
+    value: Record<string, unknown>,
+    userID: string | null = '',
+  ) {
+    this._errorBoundary.swallow(() => {
+      if (typeof value !== 'object') {
+        console.warn(
+          'statsigSDK> Attempted to override a layer with a non object value',
+        );
+        return;
+      }
+      this._evaluator.overrideLayer(layerName, value, userID);
+    });
+  }
+
   //
   // PRIVATE
   //

diff --git a/src/__tests__/LocalModeOverride.test.ts b/src/__tests__/LocalModeOverride.test.ts
@@ -124,4 +124,39 @@ describe('Test local mode with overrides', () => {
     statsig.shutdown();
     expect(hitNetwork).toEqual(false);
   });
+
+  describe('Layer overrides', () => {
+    beforeEach(async () => {
+      await statsig.initialize('secret-key', { localMode: true });
+      expect(hitNetwork).toEqual(false);
+    });
+
+    it('returns fallback values when there are no overrides', async () => {
+      let layer = await statsig.getLayer({ userID: 'a-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('fallback');
+
+      layer = await statsig.getLayer({ userID: 'b-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('fallback');
+    });
+
+    it('returns override values for a specific user', async () => {
+      statsig.overrideLayer('a_layer', { a_param: 'a_value' }, 'a-user');
+
+      let layer = await statsig.getLayer({ userID: 'a-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('a_value');
+
+      layer = await statsig.getLayer({ userID: 'b-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('fallback');
+    });
+
+    it('returns override values for all users', async () => {
+      statsig.overrideLayer('a_layer', { a_param: 'a_value' });
+
+      let layer = await statsig.getLayer({ userID: 'a-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('a_value');
+
+      layer = await statsig.getLayer({ userID: 'b-user' }, 'a_layer');
+      expect(layer.get('a_param', 'fallback')).toEqual('a_value');
+    });
+  });
 });
diff --git a/src/index.ts b/src/index.ts
@@ -160,6 +160,14 @@ const Statsig = {
     this._enforceServer().overrideConfig(configName, value, userID);
   },
 
+  overrideLayer(
+    layerName: string,
+    value: Record<string, unknown>,
+    userID = '',
+  ) {
+    this._enforceServer().overrideLayer(layerName, value, userID);
+  },
+
   flush(): Promise<void> {
     const inst = Statsig._instance;
     if (inst == null) {