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firefox/toolkit/components/nimbus/ExperimentAPI.sys.mjs
Daniel Baumann 5e9a113729
Adding upstream version 140.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-25 09:37:52 +02:00

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JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
CleanupManager: "resource://normandy/lib/CleanupManager.sys.mjs",
ExperimentManager: "resource://nimbus/lib/ExperimentManager.sys.mjs",
FeatureManifest: "resource://nimbus/FeatureManifest.sys.mjs",
NimbusMigrations: "resource://nimbus/lib/Migrations.sys.mjs",
NimbusTelemetry: "resource://nimbus/lib/Telemetry.sys.mjs",
RemoteSettings: "resource://services-settings/remote-settings.sys.mjs",
RemoteSettingsExperimentLoader:
"resource://nimbus/lib/RemoteSettingsExperimentLoader.sys.mjs",
UnenrollmentCause: "resource://nimbus/lib/ExperimentManager.sys.mjs",
});
ChromeUtils.defineLazyGetter(lazy, "log", () => {
const { Logger } = ChromeUtils.importESModule(
"resource://messaging-system/lib/Logger.sys.mjs"
);
return new Logger("ExperimentAPI");
});
const CRASHREPORTER_ENABLED =
AppConstants.MOZ_CRASHREPORTER && AppConstants.MOZ_APP_NAME !== "thunderbird";
const IS_MAIN_PROCESS =
Services.appinfo.processType === Services.appinfo.PROCESS_TYPE_DEFAULT;
const UPLOAD_ENABLED_PREF = "datareporting.healthreport.uploadEnabled";
const STUDIES_OPT_OUT_PREF = "app.shield.optoutstudies.enabled";
const COLLECTION_ID_PREF = "messaging-system.rsexperimentloader.collection_id";
const COLLECTION_ID_FALLBACK = "nimbus-desktop-experiments";
XPCOMUtils.defineLazyPreferenceGetter(
lazy,
"COLLECTION_ID",
COLLECTION_ID_PREF,
COLLECTION_ID_FALLBACK
);
function parseJSON(value) {
if (value) {
try {
return JSON.parse(value);
} catch (e) {
console.error(e);
}
}
return null;
}
const experimentBranchAccessor = {
get: (target, prop) => {
// Offer an API where we can access `branch.feature.*`.
// This is a useful shorthand that hides the fact that
// even single-feature recipes are still represented
// as an array with 1 item
if (!(prop in target) && target.features) {
return target.features.find(f => f.featureId === prop);
} else if (target.feature?.featureId === prop) {
// Backwards compatibility for version 1.6.2 and older
return target.feature;
}
return target[prop];
},
};
const NIMBUS_PROFILE_ID_PREF = "nimbus.profileId";
let cachedProfileId = null;
/**
* Ensure the Nimbus profile ID exists.
*
* @returns {string} The profile ID.
*/
function ensureNimbusProfileId() {
if (!cachedProfileId) {
if (Services.prefs.prefHasUserValue(NIMBUS_PROFILE_ID_PREF)) {
cachedProfileId = Services.prefs.getStringPref(NIMBUS_PROFILE_ID_PREF);
} else {
cachedProfileId = Services.uuid.generateUUID().toString().slice(1, -1);
Services.prefs.setStringPref(NIMBUS_PROFILE_ID_PREF, cachedProfileId);
}
}
return cachedProfileId;
}
/**
* Metadata about an enrollment.
*
* @typedef {object} EnrollmentMetadata
* @property {string} slug
* The enrollment slug.
* @property {string} branch
* The slug of the enrolled branch.
* @property {boolean} isRollout
* Whether or not the enrollment is a rollout.
*/
/**
* Return metadata about an enrollment.
*
* @param {object} enrollment
* The enrollment.
*
* @returns {EnrollmentMetadata}
* Metadata about the enrollment.
*/
function _getEnrollmentMetadata(enrollment) {
return {
slug: enrollment.slug,
branch: enrollment.branch.slug,
isRollout: enrollment.isRollout,
};
}
/**
* @typedef {"experiment"|"rollout"} EnrollmentType
*/
export const EnrollmentType = Object.freeze({
EXPERIMENT: "experiment",
ROLLOUT: "rollout",
});
let initialized = false;
let experimentManager = null;
let experimentLoader = null;
export const ExperimentAPI = {
/**
* The topic that is notified when either the studies enabled pref or the
* telemetry enabled pref changes.
*
* Consumers can listen for notifications on this topic to react to
* Nimbus being enabled or disabled.
*/
get STUDIES_ENABLED_CHANGED() {
return "nimbus:studies-enabled-changed";
},
/**
* Initialize the ExperimentAPI.
*
* This will initialize the ExperimentManager and the
* RemoteSettingsExperimentLoader. It will also trigger The
* RemoteSettingsExperimentLoader to update recipes.
*
* @param {object} options
* @param {object?} options.extraContext
* Additional context to use in the ExperimentManager's targeting
* context.
* @param {boolean?} options.forceSync
* Force the RemoteSettingsExperimentLoader to trigger a RemoteSettings
* sync before updating recipes for the first time.
*
* @returns {boolean}
* Whether or not the ExperimentAPI was initialized.
*/
async init({ extraContext, forceSync = false } = {}) {
if (initialized) {
return false;
}
ensureNimbusProfileId();
initialized = true;
const studiesEnabled = this.studiesEnabled;
try {
await lazy.NimbusMigrations.applyMigrations(
lazy.NimbusMigrations.Phase.INIT_STARTED
);
} catch (e) {
lazy.log.error(
`Failed to apply migrations in phase ${
lazy.NimbusMigrations.Phase.INIT_STARTED
}`,
e
);
}
try {
await this.manager.store.init();
} catch (e) {
lazy.log.error("Failed to initialize ExperimentStore:", e);
}
try {
await lazy.NimbusMigrations.applyMigrations(
lazy.NimbusMigrations.Phase.AFTER_STORE_INITIALIZED
);
} catch (e) {
lazy.log.error(
`Failed to apply migrations in phase ${lazy.NimbusMigrations.Phase.AFTER_STORE_INITIALIZED}`,
e
);
}
try {
await this.manager.onStartup(extraContext);
} catch (e) {
lazy.log.error("Failed to initialize ExperimentManager:", e);
}
try {
await this._rsLoader.enable({ forceSync });
} catch (e) {
lazy.log.error("Failed to enable RemoteSettingsExperimentLoader:", e);
}
try {
await lazy.NimbusMigrations.applyMigrations(
lazy.NimbusMigrations.Phase.AFTER_REMOTE_SETTINGS_UPDATE
);
} catch (e) {
lazy.log.error(
`Failed to apply migrations in phase ${
lazy.NimbusMigrations.Phase.AFTER_REMOTE_SETTINGS_UPDATE
}`,
e
);
}
if (CRASHREPORTER_ENABLED) {
this.manager.store.on("update", this._annotateCrashReport);
this._annotateCrashReport();
lazy.CleanupManager.addCleanupHandler(
ExperimentAPI._removeCrashReportAnnotator
);
}
Services.prefs.addObserver(
UPLOAD_ENABLED_PREF,
this._onStudiesEnabledChanged
);
Services.prefs.addObserver(
STUDIES_OPT_OUT_PREF,
this._onStudiesEnabledChanged
);
// If Nimbus was disabled between the start of this function and registering
// the pref observers we have not handled it yet.
if (studiesEnabled !== this.studiesEnabled) {
await this._onStudiesEnabledChanged();
}
return true;
},
/**
* Return the global ExperimentManager.
*
* The ExperimentManager will be lazily created upon first access to this
* property.
*/
get manager() {
if (experimentManager === null) {
experimentManager = new lazy.ExperimentManager();
}
return experimentManager;
},
/**
* Return the global ExperimentManager.
*
* @deprecated Use ExperimentAPI.Manager instead of this property.
*/
get _manager() {
return this.manager;
},
/**
* Return the global RemoteSettingsExperimentLoader.
*/
get _rsLoader() {
if (experimentLoader === null) {
experimentLoader = new lazy.RemoteSettingsExperimentLoader(this.manager);
}
return experimentLoader;
},
_resetForTests() {
experimentLoader?.disable();
experimentLoader = null;
lazy.CleanupManager.removeCleanupHandler(
ExperimentAPI._removeCrashReportAnnotator
);
experimentManager?.store.off("update", this._annotateCrashReport);
experimentManager = null;
initialized = false;
},
get studiesEnabled() {
return (
Services.prefs.getBoolPref(UPLOAD_ENABLED_PREF, false) &&
Services.prefs.getBoolPref(STUDIES_OPT_OUT_PREF, false) &&
Services.policies.isAllowed("Shield")
);
},
/**
* Return the profile ID.
*
* This is used to distinguish different profiles in a shared profile group
* apart. Each profile has a persistent and stable profile ID. It is stored as
* a user branch pref but is locked to prevent tampering.
*
* This is still susceptible to user.js editing, but there's nothing we can do
* about that.
*
* @returns {string} The profile ID.
*/
get profileId() {
return ensureNimbusProfileId();
},
/**
* Wait for the ExperimentAPI to become ready.
*
* NB: This method will not initialize the ExperimentAPI. This is intentional
* and doing so breaks a lot of tests due to enabling the
* RemoteSettingsExperimentLoader et al.
*
* @returns {Promise}
* A promise that resolves when the API has synchronized to the main
* store
*/
async ready() {
return this.manager.store.ready();
},
/**
* Annotate the current crash report with current enrollments.
*/
_annotateCrashReport() {
if (!Services.appinfo.crashReporterEnabled) {
return;
}
const activeEnrollments = this.manager.store
.getAll()
.filter(e => e.active)
.map(e => `${e.slug}:${e.branch.slug}`)
.join(",");
Services.appinfo.annotateCrashReport(
"NimbusEnrollments",
activeEnrollments
);
},
_removeCrashReportAnnotator() {
if (initialized) {
experimentManager?.store.off("update", this._annotateCrashReport);
}
},
async _onStudiesEnabledChanged() {
if (!this.studiesEnabled) {
await this.manager._handleStudiesOptOut();
}
await this._rsLoader.onEnabledPrefChange();
Services.obs.notifyObservers(null, this.STUDIES_ENABLED_CHANGED);
},
/**
* Returns the recipe for a given experiment slug
*
* This should noly be called from the main process.
*
* Note that the recipe is directly fetched from RemoteSettings, which has
* all the recipe metadata available without relying on the `this.manager.store`.
* Therefore, calling this function does not require to call `this.ready()` first.
*
* @param slug {String} An experiment identifier
* @returns {Recipe|undefined} A matching experiment recipe if one is found
*/
async getRecipe(slug) {
if (!IS_MAIN_PROCESS) {
throw new Error(
"getRecipe() should only be called from the main process"
);
}
let recipe;
try {
[recipe] = await this._remoteSettingsClient.get({
// Do not sync the RS store, let RemoteSettingsExperimentLoader do that
syncIfEmpty: false,
filters: { slug },
});
} catch (e) {
// If an error occurs in .get(), an empty list is returned and the destructuring
// assignment will throw.
console.error(e);
recipe = undefined;
}
return recipe;
},
/**
* Returns all the branches for a given experiment slug
*
* This should only be called from the main process. Like `getRecipe()`,
* calling this function does not require to call `this.ready()` first.
*
* @param slug {String} An experiment identifier
* @returns {[Branches]|undefined} An array of branches for the given slug
*/
async getAllBranches(slug) {
if (!IS_MAIN_PROCESS) {
throw new Error(
"getAllBranches() should only be called from the main process"
);
}
const recipe = await this.getRecipe(slug);
return recipe?.branches.map(
branch => new Proxy(branch, experimentBranchAccessor)
);
},
/**
* Opt-in to the given experiment on the given branch.
*
* @param {object} options
*
* @param {string} options.slug
* The slug of the experiment to enroll in.
*
* @param {string} options.branch
* The slug of the specific branch to enroll in.
*
* @param {string | undefined} options.collection
* The collection to fetch the recipe from. If not provided it will be fetched
* from the default experiment collection.
*
* @param {boolean | undefined} options.applyTargeting
* Whether or not to apply targeting. Defaults to false.
*
* @returns {Promise<void>}
* A promise that resolves when the enrollment is successful or rejects when
* it is unsuccessful.
*
* @throws {Error} If enrollment fails.
*/
async optInToExperiment(options) {
return this._rsLoader._optInToExperiment(options);
},
};
/**
* Singleton that holds lazy references to _ExperimentFeature instances
* defined by the FeatureManifest
*/
export const NimbusFeatures = {};
for (let feature in lazy.FeatureManifest) {
ChromeUtils.defineLazyGetter(NimbusFeatures, feature, () => {
return new _ExperimentFeature(feature);
});
}
export class _ExperimentFeature {
constructor(featureId, manifest) {
this.featureId = featureId;
this.prefGetters = {};
this.manifest = manifest || lazy.FeatureManifest[featureId];
if (!this.manifest) {
console.error(
`No manifest entry for ${featureId}. Please add one to toolkit/components/nimbus/FeatureManifest.yaml`
);
}
this._didSendExposureEvent = false;
const variables = this.manifest?.variables || {};
Object.keys(variables).forEach(key => {
const { type, fallbackPref } = variables[key];
if (fallbackPref) {
XPCOMUtils.defineLazyPreferenceGetter(
this.prefGetters,
key,
fallbackPref,
null,
() => {
ExperimentAPI.manager.store._emitFeatureUpdate(
this.featureId,
"pref-updated"
);
},
type === "json" ? parseJSON : val => val
);
}
});
}
getSetPrefName(variable) {
const setPref = this.manifest?.variables?.[variable]?.setPref;
return setPref?.pref ?? setPref ?? undefined;
}
getSetPref(variable) {
return this.manifest?.variables?.[variable]?.setPref;
}
getFallbackPrefName(variable) {
return this.manifest?.variables?.[variable]?.fallbackPref;
}
/**
* Wait for ExperimentStore to load giving access to experiment features that
* do not have a pref cache
*/
ready() {
return ExperimentAPI.ready();
}
/**
* Lookup feature variables in experiments, rollouts, and fallback prefs.
* @param {{defaultValues?: {[variableName: string]: any}}} options
* @returns {{[variableName: string]: any}} The feature value
*/
getAllVariables({ defaultValues = null } = {}) {
if (this.allowCoenrollment) {
throw new Error(
"Co-enrolling features must use the getAllEnrollments API"
);
}
let enrollment = null;
try {
enrollment = ExperimentAPI.manager.store.getExperimentForFeature(
this.featureId
);
} catch (e) {
console.error(e);
}
let featureValue = this._getLocalizedValue(enrollment);
if (typeof featureValue === "undefined") {
try {
enrollment = ExperimentAPI.manager.store.getRolloutForFeature(
this.featureId
);
} catch (e) {
console.error(e);
}
featureValue = this._getLocalizedValue(enrollment);
}
return {
...this.prefGetters,
...defaultValues,
...featureValue,
};
}
getVariable(variable) {
if (this.allowCoenrollment) {
throw new Error(
"Co-enrolling features must use the getAllEnrollments API"
);
}
if (!this.manifest?.variables?.[variable]) {
// Only throw in nightly/tests
if (Cu.isInAutomation || AppConstants.NIGHTLY_BUILD) {
throw new Error(
`Nimbus: Warning - variable "${variable}" is not defined in FeatureManifest.yaml`
);
}
}
// Next, check if an experiment is defined
let enrollment = null;
try {
enrollment = ExperimentAPI.manager.store.getExperimentForFeature(
this.featureId
);
} catch (e) {
console.error(e);
}
let value = this._getLocalizedValue(enrollment, variable);
if (typeof value !== "undefined") {
return value;
}
// Next, check for a rollout.
try {
enrollment = ExperimentAPI.manager.store.getRolloutForFeature(
this.featureId
);
} catch (e) {
console.error(e);
}
value = this._getLocalizedValue(enrollment, variable);
if (typeof value !== "undefined") {
return value;
}
// Return the default preference value
const prefName = this.getFallbackPrefName(variable);
return prefName ? this.prefGetters[variable] : undefined;
}
/**
* Return metadata about the requested enrollment that uses this feature ID.
*
* N.B.: This API cannot be used for co-enrolling features. The
* `getAllEnrollmentMetadata` API must be used instead.
*
* @param {EnrollmentType?} enrollmentType
* The type of enrollment that you want metadata for.
*
* If not provided, metadata for the active experiment
*
* @returns {EnrollmentMetadata | null}
* The metadata for the requested enrollment if one exists, otherwise
* null.
*/
getEnrollmentMetadata(enrollmentType = undefined) {
if (this.allowCoenrollment) {
throw new Error(
"Co-enrolling features must use the getAllEnrollments or getAllEnrollmentMetadata APIs"
);
}
let enrollment = null;
try {
if (typeof enrollmentType === "undefined" || enrollmentType === null) {
enrollment =
ExperimentAPI.manager.store.getExperimentForFeature(this.featureId) ??
ExperimentAPI.manager.store.getRolloutForFeature(this.featureId);
} else {
switch (enrollmentType) {
case EnrollmentType.EXPERIMENT:
enrollment = ExperimentAPI.manager.store.getExperimentForFeature(
this.featureId
);
break;
case EnrollmentType.ROLLOUT:
enrollment = ExperimentAPI.manager.store.getRolloutForFeature(
this.featureId
);
break;
}
}
} catch (e) {
lazy.log.error("Failed to get enrollment metadata:", e);
}
if (!enrollment) {
return null;
}
return _getEnrollmentMetadata(enrollment);
}
/**
* Return all active enrollments.
*
* @param {object[]}
* An array containing metadata and the feature value for every active
* enrollment using this feature.
*/
getAllEnrollments() {
return ExperimentAPI.manager.store
.getAll()
.filter(e => e.active && e.featureIds.includes(this.featureId))
.map(enrollment => {
const meta = _getEnrollmentMetadata(enrollment);
const values = this._getLocalizedValue(enrollment);
const value = {
...this.prefGetters,
...values,
};
return {
meta,
value,
};
});
}
/**
* Return metadata for all active enrollments that use this feature.
*
* @returns {object[]}
* Metadata for each active enrollment, including
* - the slug;
* - the branch slug; and
* - whether or not the enrollment is a rollout.
*/
getAllEnrollmentMetadata() {
return ExperimentAPI.manager.store
.getAll()
.filter(e => e.active && e.featureIds.includes(this.featureId))
.map(_getEnrollmentMetadata);
}
recordExposureEvent({ once = false, slug } = {}) {
if (this.allowCoenrollment && typeof slug !== "string") {
throw new Error("Co-enrolling features must provide slug");
}
if (once && this._didSendExposureEvent) {
return;
}
let metadata = null;
if (this.allowCoenrollment) {
const enrollment = ExperimentAPI.manager.store.get(slug);
if (enrollment.active) {
metadata = _getEnrollmentMetadata(enrollment);
}
} else {
metadata = this.getEnrollmentMetadata();
}
// Exposure is only sent if user is enrolled in an experiment or rollout.
if (metadata) {
lazy.NimbusTelemetry.recordExposure(
metadata.slug,
metadata.branch,
this.featureId
);
this._didSendExposureEvent = true;
}
}
onUpdate(callback) {
ExperimentAPI.manager.store._onFeatureUpdate(this.featureId, callback);
}
offUpdate(callback) {
ExperimentAPI.manager.store._offFeatureUpdate(this.featureId, callback);
}
/**
* The applications this feature applies to.
*
*/
get applications() {
return this.manifest.applications ?? ["firefox-desktop"];
}
get allowCoenrollment() {
return this.manifest.allowCoenrollment ?? false;
}
/**
* Do recursive locale substitution on the values, if applicable.
*
* If there are no localizations provided, the value will be returned as-is.
*
* If the value is an object containing an $l10n key, its substitution will be
* returned.
*
* Otherwise, the value will be recursively substituted.
*
* @param {unknown} values The values to perform substitutions upon.
* @param {Record<string, string>} localizations The localization
* substitutions for a specific locale.
* @param {Set<string>?} missingIds An optional set to collect all the IDs of
* all missing l10n entries.
*
* @returns {any} The values, potentially locale substituted.
*/
static substituteLocalizations(
values,
localizations,
missingIds = undefined
) {
const result = _ExperimentFeature._substituteLocalizations(
values,
localizations,
missingIds
);
if (missingIds?.size) {
throw new ExperimentLocalizationError(
lazy.NimbusTelemetry.ValidationFailureReason.L10N_MISSING_ENTRY
);
}
return result;
}
/**
* The implementation of localization substitution.
*
* @param {unknown} values The values to perform substitutions upon.
* @param {Record<string, string>} localizations The localization
* substitutions for a specific locale.
* @param {Set<string>?} missingIds An optional set to collect all the IDs of
* all missing l10n entries.
*
* @returns {any} The values, potentially locale substituted.
*/
static _substituteLocalizations(values, localizations, missingIds) {
// If the recipe is not localized, we don't need to do anything.
// Likewise, if the value we are attempting to localize is not an object,
// there is nothing to localize.
if (
typeof localizations === "undefined" ||
typeof values !== "object" ||
values === null
) {
return values;
}
if (Array.isArray(values)) {
return values.map(value =>
_ExperimentFeature._substituteLocalizations(
value,
localizations,
missingIds
)
);
}
const substituted = Object.assign({}, values);
for (const [key, value] of Object.entries(values)) {
if (
key === "$l10n" &&
typeof value === "object" &&
value !== null &&
value?.id
) {
if (!Object.hasOwn(localizations, value.id)) {
if (missingIds) {
missingIds.add(value.id);
break;
} else {
throw new ExperimentLocalizationError(
lazy.NimbusTelemetry.ValidationFailureReason.L10N_MISSING_ENTRY
);
}
}
return localizations[value.id];
}
substituted[key] = _ExperimentFeature._substituteLocalizations(
value,
localizations,
missingIds
);
}
return substituted;
}
/**
* Return a value (or all values) from an enrollment, potentially localized.
*
* @param {Enrollment} enrollment - The enrollment to query for the value or values.
* @param {string?} variable - The name of the variable to query for. If not
* provided, all variables will be returned.
*
* @returns {any} The value for the variable(s) in question.
*/
_getLocalizedValue(enrollment, variable = undefined) {
if (enrollment) {
const locale = Services.locale.appLocaleAsBCP47;
if (
typeof enrollment.localizations === "object" &&
enrollment.localizations !== null &&
(typeof enrollment.localizations[locale] !== "object" ||
enrollment.localizations[locale] === null)
) {
ExperimentAPI.manager._unenroll(
enrollment,
lazy.UnenrollmentCause.fromReason(
lazy.NimbusTelemetry.UnenrollReason.L10N_MISSING_LOCALE
)
);
return undefined;
}
const allValues = lazy.ExperimentManager.getFeatureConfigFromBranch(
enrollment.branch,
this.featureId
)?.value;
const value =
typeof variable === "undefined" ? allValues : allValues?.[variable];
if (typeof value !== "undefined") {
try {
return _ExperimentFeature.substituteLocalizations(
value,
enrollment.localizations?.[locale]
);
} catch (e) {
// This should never happen.
if (e instanceof ExperimentLocalizationError) {
ExperimentAPI.manager._unenroll(
enrollment,
lazy.UnenrollmentCause.fromReason(e.reason)
);
} else {
throw e;
}
}
}
}
return undefined;
}
}
ExperimentAPI._annotateCrashReport =
ExperimentAPI._annotateCrashReport.bind(ExperimentAPI);
ExperimentAPI._onStudiesEnabledChanged =
ExperimentAPI._onStudiesEnabledChanged.bind(ExperimentAPI);
ExperimentAPI._removeCrashReportAnnotator =
ExperimentAPI._removeCrashReportAnnotator.bind(ExperimentAPI);
ChromeUtils.defineLazyGetter(
ExperimentAPI,
"_remoteSettingsClient",
function () {
return lazy.RemoteSettings(lazy.COLLECTION_ID);
}
);
class ExperimentLocalizationError extends Error {
constructor(reason) {
super(`Localized experiment error (${reason})`);
this.reason = reason;
}
}