1 files changed, 290 insertions, 0 deletions
diff --git a/toolkit/components/normandy/actions/PreferenceRolloutAction.jsm b/toolkit/components/normandy/actions/PreferenceRolloutAction.jsm
new file mode 100644
index 0000000000..dc878dd43d
--- /dev/null
+++ b/toolkit/components/normandy/actions/PreferenceRolloutAction.jsm
@@ -0,0 +1,290 @@
+/* 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/. */
+
+"use strict";
+
+const { BaseAction } = ChromeUtils.import(
+  "resource://normandy/actions/BaseAction.jsm"
+);
+const lazy = {};
+ChromeUtils.defineESModuleGetters(lazy, {
+  TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.sys.mjs",
+});
+ChromeUtils.defineModuleGetter(
+  lazy,
+  "PreferenceRollouts",
+  "resource://normandy/lib/PreferenceRollouts.jsm"
+);
+ChromeUtils.defineModuleGetter(
+  lazy,
+  "PrefUtils",
+  "resource://normandy/lib/PrefUtils.jsm"
+);
+ChromeUtils.defineModuleGetter(
+  lazy,
+  "ActionSchemas",
+  "resource://normandy/actions/schemas/index.js"
+);
+ChromeUtils.defineModuleGetter(
+  lazy,
+  "TelemetryEvents",
+  "resource://normandy/lib/TelemetryEvents.jsm"
+);
+ChromeUtils.defineModuleGetter(
+  lazy,
+  "NormandyUtils",
+  "resource://normandy/lib/NormandyUtils.jsm"
+);
+
+var EXPORTED_SYMBOLS = ["PreferenceRolloutAction"];
+
+const PREFERENCE_TYPE_MAP = {
+  boolean: Services.prefs.PREF_BOOL,
+  string: Services.prefs.PREF_STRING,
+  number: Services.prefs.PREF_INT,
+};
+
+class PreferenceRolloutAction extends BaseAction {
+  get schema() {
+    return lazy.ActionSchemas["preference-rollout"];
+  }
+
+  async _run(recipe) {
+    const args = recipe.arguments;
+
+    // Check if the rollout is on the list of rollouts to stop applying.
+    if (lazy.PreferenceRollouts.GRADUATION_SET.has(args.slug)) {
+      this.log.debug(
+        `Skipping rollout "${args.slug}" because it is in the graduation set.`
+      );
+      return;
+    }
+
+    // Determine which preferences are already being managed, to avoid
+    // conflicts between recipes. This will throw if there is a problem.
+    await this._verifyRolloutPrefs(args);
+
+    const newRollout = {
+      slug: args.slug,
+      state: "active",
+      preferences: args.preferences.map(({ preferenceName, value }) => ({
+        preferenceName,
+        value,
+        previousValue: lazy.PrefUtils.getPref(preferenceName, {
+          branch: "default",
+        }),
+      })),
+    };
+
+    const existingRollout = await lazy.PreferenceRollouts.get(args.slug);
+    if (existingRollout) {
+      const anyChanged = await this._updatePrefsForExistingRollout(
+        existingRollout,
+        newRollout
+      );
+
+      // If anything was different about the new rollout, write it to the db and send an event about it
+      if (anyChanged) {
+        await lazy.PreferenceRollouts.update(newRollout);
+        lazy.TelemetryEvents.sendEvent(
+          "update",
+          "preference_rollout",
+          args.slug,
+          {
+            previousState: existingRollout.state,
+            enrollmentId:
+              existingRollout.enrollmentId ||
+              lazy.TelemetryEvents.NO_ENROLLMENT_ID_MARKER,
+          }
+        );
+
+        switch (existingRollout.state) {
+          case lazy.PreferenceRollouts.STATE_ACTIVE: {
+            this.log.debug(`Updated preference rollout ${args.slug}`);
+            break;
+          }
+          case lazy.PreferenceRollouts.STATE_GRADUATED: {
+            this.log.debug(`Ungraduated preference rollout ${args.slug}`);
+            lazy.TelemetryEnvironment.setExperimentActive(
+              args.slug,
+              newRollout.state,
+              { type: "normandy-prefrollout" }
+            );
+            break;
+          }
+          default: {
+            Cu.reportError(
+              new Error(
+                `Updated pref rollout in unexpected state: ${existingRollout.state}`
+              )
+            );
+          }
+        }
+      } else {
+        this.log.debug(`No updates to preference rollout ${args.slug}`);
+      }
+    } else {
+      // new enrollment
+      // Check if this rollout would be a no-op, which is not allowed.
+      if (
+        newRollout.preferences.every(
+          ({ value, previousValue }) => value === previousValue
+        )
+      ) {
+        lazy.TelemetryEvents.sendEvent(
+          "enrollFailed",
+          "preference_rollout",
+          args.slug,
+          { reason: "would-be-no-op" }
+        );
+        // Throw so that this recipe execution is marked as a failure
+        throw new Error(
+          `New rollout ${args.slug} does not change any preferences.`
+        );
+      }
+
+      let enrollmentId = lazy.NormandyUtils.generateUuid();
+      newRollout.enrollmentId = enrollmentId;
+
+      await lazy.PreferenceRollouts.add(newRollout);
+
+      for (const { preferenceName, value } of args.preferences) {
+        lazy.PrefUtils.setPref(preferenceName, value, { branch: "default" });
+      }
+
+      this.log.debug(`Enrolled in preference rollout ${args.slug}`);
+      lazy.TelemetryEnvironment.setExperimentActive(
+        args.slug,
+        newRollout.state,
+        {
+          type: "normandy-prefrollout",
+          enrollmentId:
+            enrollmentId || lazy.TelemetryEvents.NO_ENROLLMENT_ID_MARKER,
+        }
+      );
+      lazy.TelemetryEvents.sendEvent(
+        "enroll",
+        "preference_rollout",
+        args.slug,
+        {
+          enrollmentId:
+            enrollmentId || lazy.TelemetryEvents.NO_ENROLLMENT_ID_MARKER,
+        }
+      );
+    }
+  }
+
+  /**
+   * Check that all the preferences in a rollout are ok to set. This means 1) no
+   * other rollout is managing them, and 2) they match the types of the builtin
+   * values.
+   * @param {PreferenceRollout} rollout The arguments from a rollout recipe.
+   * @throws If the preferences are not valid, with details in the error message.
+   */
+  async _verifyRolloutPrefs({ slug, preferences }) {
+    const existingManagedPrefs = new Set();
+    for (const rollout of await lazy.PreferenceRollouts.getAllActive()) {
+      if (rollout.slug === slug) {
+        continue;
+      }
+      for (const prefSpec of rollout.preferences) {
+        existingManagedPrefs.add(prefSpec.preferenceName);
+      }
+    }
+
+    for (const prefSpec of preferences) {
+      if (existingManagedPrefs.has(prefSpec.preferenceName)) {
+        lazy.TelemetryEvents.sendEvent(
+          "enrollFailed",
+          "preference_rollout",
+          slug,
+          {
+            reason: "conflict",
+            preference: prefSpec.preferenceName,
+          }
+        );
+        // Throw so that this recipe execution is marked as a failure
+        throw new Error(
+          `Cannot start rollout ${slug}. Preference ${prefSpec.preferenceName} is already managed.`
+        );
+      }
+      const existingPrefType = Services.prefs.getPrefType(
+        prefSpec.preferenceName
+      );
+      const rolloutPrefType = PREFERENCE_TYPE_MAP[typeof prefSpec.value];
+
+      if (
+        existingPrefType !== Services.prefs.PREF_INVALID &&
+        existingPrefType !== rolloutPrefType
+      ) {
+        lazy.TelemetryEvents.sendEvent(
+          "enrollFailed",
+          "preference_rollout",
+          slug,
+          {
+            reason: "invalid type",
+            preference: prefSpec.preferenceName,
+          }
+        );
+        // Throw so that this recipe execution is marked as a failure
+        throw new Error(
+          `Cannot start rollout "${slug}" on "${prefSpec.preferenceName}". ` +
+            `Existing preference is of type ${existingPrefType}, but rollout ` +
+            `specifies type ${rolloutPrefType}`
+        );
+      }
+    }
+  }
+
+  async _updatePrefsForExistingRollout(existingRollout, newRollout) {
+    let anyChanged = false;
+    const oldPrefSpecs = new Map(
+      existingRollout.preferences.map(p => [p.preferenceName, p])
+    );
+    const newPrefSpecs = new Map(
+      newRollout.preferences.map(p => [p.preferenceName, p])
+    );
+
+    // Check for any preferences that no longer exist, and un-set them.
+    for (const { preferenceName, previousValue } of oldPrefSpecs.values()) {
+      if (!newPrefSpecs.has(preferenceName)) {
+        this.log.debug(
+          `updating ${existingRollout.slug}: ${preferenceName} no longer exists`
+        );
+        anyChanged = true;
+        lazy.PrefUtils.setPref(preferenceName, previousValue, {
+          branch: "default",
+        });
+      }
+    }
+
+    // Check for any preferences that are new and need added, or changed and need updated.
+    for (const prefSpec of Object.values(newRollout.preferences)) {
+      let oldValue = null;
+      if (oldPrefSpecs.has(prefSpec.preferenceName)) {
+        let oldPrefSpec = oldPrefSpecs.get(prefSpec.preferenceName);
+        oldValue = oldPrefSpec.value;
+
+        // Trust the old rollout for the values of `previousValue`, but don't
+        // consider this a change, since it already matches the DB, and doesn't
+        // have any other stateful effect.
+        prefSpec.previousValue = oldPrefSpec.previousValue;
+      }
+      if (oldValue !== newPrefSpecs.get(prefSpec.preferenceName).value) {
+        anyChanged = true;
+        this.log.debug(
+          `updating ${existingRollout.slug}: ${prefSpec.preferenceName} value changed from ${oldValue} to ${prefSpec.value}`
+        );
+        lazy.PrefUtils.setPref(prefSpec.preferenceName, prefSpec.value, {
+          branch: "default",
+        });
+      }
+    }
+    return anyChanged;
+  }
+
+  async _finalize() {
+    await lazy.PreferenceRollouts.saveStartupPrefs();
+  }
+}