revert revert allocation id change

Author: zhiyuanliang-ms

src/AzureAppConfigurationImpl.ts

@@ -9,6 +9,7 @@ import { IKeyValueAdapter } from "./IKeyValueAdapter.js";
 import { JsonKeyValueAdapter } from "./JsonKeyValueAdapter.js";
 import { DEFAULT_REFRESH_INTERVAL_IN_MS, MIN_REFRESH_INTERVAL_IN_MS } from "./RefreshOptions.js";
 import { Disposable } from "./common/disposable.js";
+import { base64Helper, jsonSorter } from "./common/utils.js";
 import {
     FEATURE_FLAGS_KEY_NAME,
     FEATURE_MANAGEMENT_KEY_NAME,
@@ -19,9 +20,16 @@ import {
     ETAG_KEY_NAME,
     FEATURE_FLAG_ID_KEY_NAME,
     FEATURE_FLAG_REFERENCE_KEY_NAME,
+    ALLOCATION_ID_KEY_NAME,
     ALLOCATION_KEY_NAME,
+    DEFAULT_WHEN_ENABLED_KEY_NAME,
+    PERCENTILE_KEY_NAME,
+    FROM_KEY_NAME,
+    TO_KEY_NAME,
     SEED_KEY_NAME,
+    VARIANT_KEY_NAME,
     VARIANTS_KEY_NAME,
+    CONFIGURATION_VALUE_KEY_NAME,
     CONDITIONS_KEY_NAME,
     CLIENT_FILTERS_KEY_NAME
 } from "./featureManagement/constants.js";
@@ -669,10 +677,15 @@ export class AzureAppConfigurationImpl implements AzureAppConfiguration {
 
         if (featureFlag[TELEMETRY_KEY_NAME] && featureFlag[TELEMETRY_KEY_NAME][ENABLED_KEY_NAME] === true) {
             const metadata = featureFlag[TELEMETRY_KEY_NAME][METADATA_KEY_NAME];
+            let allocationId = "";
+            if (featureFlag[ALLOCATION_KEY_NAME] !== undefined) {
+                allocationId = await this.#generateAllocationId(featureFlag);
+            }
             featureFlag[TELEMETRY_KEY_NAME][METADATA_KEY_NAME] = {
                 [ETAG_KEY_NAME]: setting.etag,
                 [FEATURE_FLAG_ID_KEY_NAME]: await this.#calculateFeatureFlagId(setting),
                 [FEATURE_FLAG_REFERENCE_KEY_NAME]: this.#createFeatureFlagReference(setting),
+                ...(allocationId !== "" && { [ALLOCATION_ID_KEY_NAME]: allocationId }),
                 ...(metadata || {})
             };
         }
@@ -756,6 +769,116 @@ export class AzureAppConfigurationImpl implements AzureAppConfiguration {
         }
         return featureFlagReference;
     }
+
+    async #generateAllocationId(featureFlag: any): Promise<string> {
+        let rawAllocationId = "";
+        // Only default variant when enabled and variants allocated by percentile involve in the experimentation
+        // The allocation id is genearted from default variant when enabled and percentile allocation
+        const variantsForExperimentation: string[] = [];
+
+        rawAllocationId += `seed=${featureFlag[ALLOCATION_KEY_NAME][SEED_KEY_NAME] ?? ""}\ndefault_when_enabled=`;
+
+        if (featureFlag[ALLOCATION_KEY_NAME][DEFAULT_WHEN_ENABLED_KEY_NAME]) {
+            variantsForExperimentation.push(featureFlag[ALLOCATION_KEY_NAME][DEFAULT_WHEN_ENABLED_KEY_NAME]);
+            rawAllocationId += `${featureFlag[ALLOCATION_KEY_NAME][DEFAULT_WHEN_ENABLED_KEY_NAME]}`;
+        }
+
+        rawAllocationId += "\npercentiles=";
+
+        const percentileList = featureFlag[ALLOCATION_KEY_NAME][PERCENTILE_KEY_NAME];
+        if (percentileList) {
+            const sortedPercentileList = percentileList
+                .filter(p =>
+                    (p[FROM_KEY_NAME] !== undefined) &&
+                    (p[TO_KEY_NAME] !== undefined) &&
+                    (p[VARIANT_KEY_NAME] !== undefined) &&
+                    (p[FROM_KEY_NAME] !== p[TO_KEY_NAME]))
+                .sort((a, b) => a[FROM_KEY_NAME] - b[FROM_KEY_NAME]);
+
+            const percentileAllocation: string[] = [];
+            for (const percentile of sortedPercentileList) {
+                variantsForExperimentation.push(percentile[VARIANT_KEY_NAME]);
+                percentileAllocation.push(`${percentile[FROM_KEY_NAME]},${base64Helper(percentile[VARIANT_KEY_NAME])},${percentile[TO_KEY_NAME]}`);
+            }
+            rawAllocationId += percentileAllocation.join(";");
+        }
+
+        if (variantsForExperimentation.length === 0 && featureFlag[ALLOCATION_KEY_NAME][SEED_KEY_NAME] === undefined) {
+            // All fields required for generating allocation id are missing, short-circuit and return empty string
+            return "";
+        }
+
+        rawAllocationId += "\nvariants=";
+
+        if (variantsForExperimentation.length !== 0) {
+            const variantsList = featureFlag[VARIANTS_KEY_NAME];
+            if (variantsList) {
+                const sortedVariantsList = variantsList
+                    .filter(v =>
+                        (v[NAME_KEY_NAME] !== undefined) &&
+                        variantsForExperimentation.includes(v[NAME_KEY_NAME]))
+                    .sort((a, b) => (a.name > b.name ? 1 : -1));
+
+                    const variantConfiguration: string[] = [];
+                    for (const variant of sortedVariantsList) {
+                        const configurationValue = JSON.stringify(variant[CONFIGURATION_VALUE_KEY_NAME], jsonSorter) ?? "";
+                        variantConfiguration.push(`${base64Helper(variant[NAME_KEY_NAME])},${configurationValue}`);
+                    }
+                    rawAllocationId += variantConfiguration.join(";");
+            }
+        }
+
+        let crypto;
+
+        // Check for browser environment
+        if (typeof window !== "undefined" && window.crypto && window.crypto.subtle) {
+            crypto = window.crypto;
+        }
+        // Check for Node.js environment
+        else if (typeof global !== "undefined" && global.crypto) {
+            crypto = global.crypto;
+        }
+        // Fallback to native Node.js crypto module
+        else {
+            try {
+                if (typeof module !== "undefined" && module.exports) {
+                    crypto = require("crypto");
+                }
+                else {
+                    crypto = await import("crypto");
+                }
+            } catch (error) {
+                console.error("Failed to load the crypto module:", error.message);
+                throw error;
+            }
+        }
+
+        // Convert to UTF-8 encoded bytes
+        const data = new TextEncoder().encode(rawAllocationId);
+
+        // In the browser, use crypto.subtle.digest
+        if (crypto.subtle) {
+            const hashBuffer = await crypto.subtle.digest("SHA-256", data);
+            const hashArray = new Uint8Array(hashBuffer);
+
+            // Only use the first 15 bytes
+            const first15Bytes = hashArray.slice(0, 15);
+
+            // btoa/atob is also available in Node.js 18+
+            const base64String = btoa(String.fromCharCode(...first15Bytes));
+            const base64urlString = base64String.replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/, "");
+            return base64urlString;
+        }
+        // In Node.js, use the crypto module's hash function
+        else {
+            const hash = crypto.createHash("sha256").update(data).digest();
+
+            // Only use the first 15 bytes
+            const first15Bytes = hash.slice(0, 15);
+
+            return first15Bytes.toString("base64url");
+        }
+    }
 }
 
 function getValidSelectors(selectors: SettingSelector[]): SettingSelector[] {

src/common/utils.ts

@@ -1,10 +1,32 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
 
+export function base64Helper(str: string): string {
+    const bytes = new TextEncoder().encode(str); // UTF-8 encoding
+    let chars = "";
+    for (let i = 0; i < bytes.length; i++) {
+        chars += String.fromCharCode(bytes[i]);
+    }
+    return btoa(chars);
+}
+
+export function jsonSorter(key, value) {
+    if (value === null) {
+        return null;
+    }
+    if (Array.isArray(value)) {
+        return value;
+    }
+    if (typeof value === "object") {
+        return Object.fromEntries(Object.entries(value).sort());
+    }
+    return value;
+}
+
 export function shuffleList<T>(array: T[]): T[] {
-  for (let i = array.length - 1; i > 0; i--) {
-    const j = Math.floor(Math.random() * (i + 1));
-    [array[i], array[j]] = [array[j], array[i]];
-  }
-  return array;
+    for (let i = array.length - 1; i > 0; i--) {
+        const j = Math.floor(Math.random() * (i + 1));
+        [array[i], array[j]] = [array[j], array[i]];
+    }
+    return array;
 }

test/featureFlag.test.ts

@@ -339,4 +339,65 @@ describe("feature flags", function () {
         expect(featureFlag.telemetry.metadata.FeatureFlagId).equals("Rc8Am7HIGDT7HC5Ovs3wKN_aGaaK_Uz1mH2e11gaK0o");
         expect(featureFlag.telemetry.metadata.FeatureFlagReference).equals(`${createMockedEndpoint()}/kv/.appconfig.featureflag/Telemetry_2?label=Test`);
     });
+
+    
+    it("should not populate allocation id", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            featureFlagOptions: {
+                enabled: true,
+                selectors: [ { keyFilter: "*" } ]
+            }
+        });
+        expect(settings).not.undefined;
+        expect(settings.get("feature_management")).not.undefined;
+        const featureFlags = settings.get<any>("feature_management").feature_flags;
+        expect(featureFlags).not.undefined;
+
+        const NoPercentileAndSeed = (featureFlags as any[]).find(item => item.id === "NoPercentileAndSeed");
+        expect(NoPercentileAndSeed).not.undefined;
+        expect(NoPercentileAndSeed?.telemetry.metadata.AllocationId).to.be.undefined;
+    });
+
+    it("should populate allocation id", async () => {
+        const connectionString = createMockedConnectionString();
+        const settings = await load(connectionString, {
+            featureFlagOptions: {
+                enabled: true,
+                selectors: [ { keyFilter: "*" } ]
+            }
+        });
+        expect(settings).not.undefined;
+        expect(settings.get("feature_management")).not.undefined;
+        const featureFlags = settings.get<any>("feature_management").feature_flags;
+        expect(featureFlags).not.undefined;
+
+        const SeedOnly = (featureFlags as any[]).find(item => item.id === "SeedOnly");
+        expect(SeedOnly).not.undefined;
+        expect(SeedOnly?.telemetry.metadata.AllocationId).equals("qZApcKdfXscxpgn_8CMf");
+
+        const DefaultWhenEnabledOnly = (featureFlags as any[]).find(item => item.id === "DefaultWhenEnabledOnly");
+        expect(DefaultWhenEnabledOnly).not.undefined;
+        expect(DefaultWhenEnabledOnly?.telemetry.metadata.AllocationId).equals("k486zJjud_HkKaL1C4qB");
+
+        const PercentileOnly = (featureFlags as any[]).find(item => item.id === "PercentileOnly");
+        expect(PercentileOnly).not.undefined;
+        expect(PercentileOnly?.telemetry.metadata.AllocationId).equals("5YUbmP0P5s47zagO_LvI");
+
+        const SimpleConfigurationValue = (featureFlags as any[]).find(item => item.id === "SimpleConfigurationValue");
+        expect(SimpleConfigurationValue).not.undefined;
+        expect(SimpleConfigurationValue?.telemetry.metadata.AllocationId).equals("QIOEOTQJr2AXo4dkFFqy");
+
+        const ComplexConfigurationValue = (featureFlags as any[]).find(item => item.id === "ComplexConfigurationValue");
+        expect(ComplexConfigurationValue).not.undefined;
+        expect(ComplexConfigurationValue?.telemetry.metadata.AllocationId).equals("4Bes0AlwuO8kYX-YkBWs");
+
+        const TelemetryVariantPercentile = (featureFlags as any[]).find(item => item.id === "TelemetryVariantPercentile");
+        expect(TelemetryVariantPercentile).not.undefined;
+        expect(TelemetryVariantPercentile?.telemetry.metadata.AllocationId).equals("YsdJ4pQpmhYa8KEhRLUn");
+
+        const Complete = (featureFlags as any[]).find(item => item.id === "Complete");
+        expect(Complete).not.undefined;
+        expect(Complete?.telemetry.metadata.AllocationId).equals("DER2rF-ZYog95c4CBZoi");
+    });
 });