Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1313 insertions, 0 deletions

diff --git a/services/sync/modules/telemetry.sys.mjs b/services/sync/modules/telemetry.sys.mjs
new file mode 100644
index 0000000000..9a12be9714
--- /dev/null
+++ b/services/sync/modules/telemetry.sys.mjs
@@ -0,0 +1,1313 @@
+/* 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/. */
+
+// Support for Sync-and-FxA-related telemetry, which is submitted in a special-purpose
+// telemetry ping called the "sync ping", documented here:
+//
+//  ../../../toolkit/components/telemetry/docs/data/sync-ping.rst
+//
+// The sync ping contains identifiers that are linked to the user's Firefox Account
+// and are separate from the main telemetry client_id, so this file is also responsible
+// for ensuring that we can delete those pings upon user request, by plumbing its
+// identifiers into the "deletion-request" ping.
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+import { Log } from "resource://gre/modules/Log.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Async: "resource://services-common/async.sys.mjs",
+  AuthenticationError: "resource://services-sync/sync_auth.sys.mjs",
+  FxAccounts: "resource://gre/modules/FxAccounts.sys.mjs",
+  Observers: "resource://services-common/observers.sys.mjs",
+  Resource: "resource://services-sync/resource.sys.mjs",
+  Status: "resource://services-sync/status.sys.mjs",
+  Svc: "resource://services-sync/util.sys.mjs",
+  TelemetryController: "resource://gre/modules/TelemetryController.sys.mjs",
+  TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.sys.mjs",
+  TelemetryUtils: "resource://gre/modules/TelemetryUtils.sys.mjs",
+  Weave: "resource://services-sync/main.sys.mjs",
+});
+
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  ObjectUtils: "resource://gre/modules/ObjectUtils.jsm",
+});
+
+XPCOMUtils.defineLazyGetter(lazy, "fxAccounts", () => {
+  return ChromeUtils.importESModule(
+    "resource://gre/modules/FxAccounts.sys.mjs"
+  ).getFxAccountsSingleton();
+});
+
+import * as constants from "resource://services-sync/constants.sys.mjs";
+
+XPCOMUtils.defineLazyGetter(
+  lazy,
+  "WeaveService",
+  () => Cc["@mozilla.org/weave/service;1"].getService().wrappedJSObject
+);
+const log = Log.repository.getLogger("Sync.Telemetry");
+
+const TOPICS = [
+  // For tracking change to account/device identifiers.
+  "fxaccounts:new_device_id",
+  "fxaccounts:onlogout",
+  "weave:service:ready",
+  "weave:service:login:got-hashed-id",
+
+  // For whole-of-sync metrics.
+  "weave:service:sync:start",
+  "weave:service:sync:finish",
+  "weave:service:sync:error",
+
+  // For individual engine metrics.
+  "weave:engine:sync:start",
+  "weave:engine:sync:finish",
+  "weave:engine:sync:error",
+  "weave:engine:sync:applied",
+  "weave:engine:sync:step",
+  "weave:engine:sync:uploaded",
+  "weave:engine:validate:finish",
+  "weave:engine:validate:error",
+
+  // For ad-hoc telemetry events.
+  "weave:telemetry:event",
+  "weave:telemetry:histogram",
+  "fxa:telemetry:event",
+
+  "weave:telemetry:migration",
+];
+
+const PING_FORMAT_VERSION = 1;
+
+const EMPTY_UID = "0".repeat(32);
+
+// The set of engines we record telemetry for - any other engines are ignored.
+const ENGINES = new Set([
+  "addons",
+  "bookmarks",
+  "clients",
+  "forms",
+  "history",
+  "passwords",
+  "prefs",
+  "tabs",
+  "extension-storage",
+  "addresses",
+  "creditcards",
+]);
+
+function tryGetMonotonicTimestamp() {
+  try {
+    return Services.telemetry.msSinceProcessStart();
+  } catch (e) {
+    log.warn("Unable to get a monotonic timestamp!");
+    return -1;
+  }
+}
+
+function timeDeltaFrom(monotonicStartTime) {
+  let now = tryGetMonotonicTimestamp();
+  if (monotonicStartTime !== -1 && now !== -1) {
+    return Math.round(now - monotonicStartTime);
+  }
+  return -1;
+}
+
+const NS_ERROR_MODULE_BASE_OFFSET = 0x45;
+const NS_ERROR_MODULE_NETWORK = 6;
+
+// A reimplementation of NS_ERROR_GET_MODULE, which surprisingly doesn't seem
+// to exist anywhere in .js code in a way that can be reused.
+// This is taken from DownloadCore.sys.mjs.
+function NS_ERROR_GET_MODULE(code) {
+  return ((code & 0x7fff0000) >> 16) - NS_ERROR_MODULE_BASE_OFFSET;
+}
+
+// Converts extra integer fields to strings, rounds floats to three
+// decimal places (nanosecond precision for timings), and removes profile
+// directory paths and URLs from potential error messages.
+function normalizeExtraTelemetryFields(extra) {
+  let result = {};
+  for (let key in extra) {
+    let value = extra[key];
+    let type = typeof value;
+    if (type == "string") {
+      result[key] = ErrorSanitizer.cleanErrorMessage(value);
+    } else if (type == "number") {
+      result[key] = Number.isInteger(value)
+        ? value.toString(10)
+        : value.toFixed(3);
+    } else if (type != "undefined") {
+      throw new TypeError(
+        `Invalid type ${type} for extra telemetry field ${key}`
+      );
+    }
+  }
+  return lazy.ObjectUtils.isEmpty(result) ? undefined : result;
+}
+
+// Keps track of the counts of individual records fate during a sync cycle
+// The main reason this is a class is to keep track of reasons individual records
+// failure reasons without huge memory overhead.
+export class SyncedRecordsTelemetry {
+  // applied    => number of items that should be applied.
+  // failed     => number of items that failed in this sync.
+  // newFailed  => number of items that failed for the first time in this sync.
+  // reconciled => number of items that were reconciled.
+  // failedReasons => {name, count} of reasons a record failed
+  incomingCounts = {
+    applied: 0,
+    failed: 0,
+    newFailed: 0,
+    reconciled: 0,
+    failedReasons: null,
+  };
+  outgoingCounts = { failed: 0, sent: 0, failedReasons: null };
+
+  addIncomingFailedReason(reason) {
+    if (!this.incomingCounts.failedReasons) {
+      this.incomingCounts.failedReasons = [];
+    }
+    let transformedReason = SyncTelemetry.transformError(reason);
+    // Some errors like http/nss errors don't have an error object
+    // those will be caught by the higher level telemetry
+    if (!transformedReason.error) {
+      return;
+    }
+
+    let index = this.incomingCounts.failedReasons.findIndex(
+      reasons => reasons.name === transformedReason.error
+    );
+
+    if (index >= 0) {
+      this.incomingCounts.failedReasons[index].count += 1;
+    } else {
+      this.incomingCounts.failedReasons.push({
+        name: transformedReason.error,
+        count: 1,
+      });
+    }
+  }
+
+  addOutgoingFailedReason(reason) {
+    if (!this.outgoingCounts.failedReasons) {
+      this.outgoingCounts.failedReasons = [];
+    }
+    let transformedReason = SyncTelemetry.transformError(reason);
+    // Some errors like http/nss errors don't have an error object
+    // those will be caught by the higher level telemetry
+    if (!transformedReason.error) {
+      return;
+    }
+    let index = this.outgoingCounts.failedReasons.findIndex(
+      reasons => reasons.name === transformedReason.error
+    );
+    if (index >= 0) {
+      this.outgoingCounts.failedReasons[index].count += 1;
+    } else {
+      this.outgoingCounts.failedReasons.push({
+        name: transformedReason.error,
+        count: 1,
+      });
+    }
+  }
+}
+
+// The `ErrorSanitizer` has 2 main jobs:
+// * Remove PII from errors, such as the profile dir or URLs the user might
+//   have visited.
+// * Normalize errors so different locales or operating systems etc don't
+//   generate different messages for the same underlying error.
+// * [TODO] Normalize errors so environmental factors don't influence message.
+//   For example, timestamps or GUIDs should be replaced with something static.
+export class ErrorSanitizer {
+  // Things we normalize - this isn't exhaustive, but covers the common error messages we see.
+  // Eg:
+  // > Win error 112 during operation write on file [profileDir]\weave\addonsreconciler.json (Espacio en disco insuficiente. )
+  // > Win error 112 during operation write on file [profileDir]\weave\addonsreconciler.json (Diskte yeterli yer yok. )
+  // > <snip many other translations of the error>
+  // > Unix error 28 during operation write on file [profileDir]/weave/addonsreconciler.json (No space left on device)
+  // These tend to crowd out other errors we might care about (eg, top 5 errors for some engines are
+  // variations of the "no space left on device")
+
+  // Note that only errors that have same-but-different errors on Windows and Unix are here - we
+  // still sanitize ones that aren't in these maps to remove the translations etc - eg,
+  // `ERROR_SHARING_VIOLATION` doesn't really have a unix equivalent, so doesn't appear here, but
+  // we still strip the translations to avoid the variants.
+  static E_NO_SPACE_ON_DEVICE = "OS error [No space left on device]";
+  static E_PERMISSION_DENIED = "OS error [Permission denied]";
+  static E_NO_FILE_OR_DIR = "OS error [File/Path not found]";
+  static E_NO_MEM = "OS error [No memory]";
+
+  static WindowsErrorSubstitutions = {
+    2: this.E_NO_FILE_OR_DIR, // ERROR_FILE_NOT_FOUND
+    3: this.E_NO_FILE_OR_DIR, // ERROR_PATH_NOT_FOUND
+    5: this.E_PERMISSION_DENIED, // ERROR_ACCESS_DENIED
+    8: this.E_NO_MEM, // ERROR_NOT_ENOUGH_MEMORY
+    112: this.E_NO_SPACE_ON_DEVICE, // ERROR_DISK_FULL
+  };
+
+  static UnixErrorSubstitutions = {
+    2: this.E_NO_FILE_OR_DIR, // ENOENT
+    12: this.E_NO_MEM, // ENOMEM
+    13: this.E_PERMISSION_DENIED, // EACCESS
+    28: this.E_NO_SPACE_ON_DEVICE, // ENOSPC
+  };
+
+  static DOMErrorSubstitutions = {
+    NotFoundError: this.E_NO_FILE_OR_DIR,
+    NotAllowedError: this.E_PERMISSION_DENIED,
+  };
+
+  static reWinError =
+    /^(?<head>Win error (?<errno>\d+))(?<detail>.*) \(.*\r?\n?\)$/m;
+  static reUnixError =
+    /^(?<head>Unix error (?<errno>\d+))(?<detail>.*) \(.*\)$/;
+
+  static #cleanOSErrorMessage(message, error = undefined) {
+    if (DOMException.isInstance(error)) {
+      const sub = this.DOMErrorSubstitutions[error.name];
+      message = message.replaceAll("\\", "/");
+      if (sub) {
+        return `${sub} ${message}`;
+      }
+    }
+
+    let match = this.reWinError.exec(message);
+    if (match) {
+      let head =
+        this.WindowsErrorSubstitutions[match.groups.errno] || match.groups.head;
+      return head + match.groups.detail.replaceAll("\\", "/");
+    }
+    match = this.reUnixError.exec(message);
+    if (match) {
+      let head =
+        this.UnixErrorSubstitutions[match.groups.errno] || match.groups.head;
+      return head + match.groups.detail;
+    }
+    return message;
+  }
+
+  // A regex we can use to replace the profile dir in error messages. We use a
+  // regexp so we can simply replace all case-insensitive occurences.
+  // This escaping function is from:
+  // https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions
+  static reProfileDir = new RegExp(
+    PathUtils.profileDir.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"),
+    "gi"
+  );
+
+  /**
+   * Clean an error message, removing PII and normalizing OS-specific messages.
+   *
+   * @param {string} message The error message
+   * @param {Error?} error The error class instance, if any.
+   */
+  static cleanErrorMessage(message, error = undefined) {
+    // There's a chance the profiledir is in the error string which is PII we
+    // want to avoid including in the ping.
+    message = message.replace(this.reProfileDir, "[profileDir]");
+    // MSG_INVALID_URL from /dom/bindings/Errors.msg -- no way to access this
+    // directly from JS.
+    if (message.endsWith("is not a valid URL.")) {
+      message = "<URL> is not a valid URL.";
+    }
+    // Try to filter things that look somewhat like a URL (in that they contain a
+    // colon in the middle of non-whitespace), in case anything else is including
+    // these in error messages. Note that JSON.stringified stuff comes through
+    // here, so we explicitly ignore double-quotes as well.
+    message = message.replace(/[^\s"]+:[^\s"]+/g, "<URL>");
+
+    // Anywhere that's normalized the guid in errors we can easily filter
+    // to make it easier to aggregate these types of errors
+    message = message.replace(/<guid: ([^>]+)>/g, "<GUID>");
+
+    return this.#cleanOSErrorMessage(message, error);
+  }
+}
+
+// This function validates the payload of a telemetry "event" - this can be
+// removed once there are APIs available for the telemetry modules to collect
+// these events (bug 1329530) - but for now we simulate that planned API as
+// best we can.
+function validateTelemetryEvent(eventDetails) {
+  let { object, method, value, extra } = eventDetails;
+  // Do do basic validation of the params - everything except "extra" must
+  // be a string. method and object are required.
+  if (
+    typeof method != "string" ||
+    typeof object != "string" ||
+    (value && typeof value != "string") ||
+    (extra && typeof extra != "object")
+  ) {
+    log.warn("Invalid event parameters - wrong types", eventDetails);
+    return false;
+  }
+  // length checks.
+  if (
+    method.length > 20 ||
+    object.length > 20 ||
+    (value && value.length > 80)
+  ) {
+    log.warn("Invalid event parameters - wrong lengths", eventDetails);
+    return false;
+  }
+
+  // extra can be falsey, or an object with string names and values.
+  if (extra) {
+    if (Object.keys(extra).length > 10) {
+      log.warn("Invalid event parameters - too many extra keys", eventDetails);
+      return false;
+    }
+    for (let [ename, evalue] of Object.entries(extra)) {
+      if (
+        typeof ename != "string" ||
+        ename.length > 15 ||
+        typeof evalue != "string" ||
+        evalue.length > 85
+      ) {
+        log.warn(
+          `Invalid event parameters: extra item "${ename} is invalid`,
+          eventDetails
+        );
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+class EngineRecord {
+  constructor(name) {
+    // startTime is in ms from process start, but is monotonic (unlike Date.now())
+    // so we need to keep both it and when.
+    this.startTime = tryGetMonotonicTimestamp();
+    this.name = name;
+
+    // This allows cases like bookmarks-buffered to have a separate name from
+    // the bookmarks engine.
+    let engineImpl = lazy.Weave.Service.engineManager.get(name);
+    if (engineImpl && engineImpl.overrideTelemetryName) {
+      this.overrideTelemetryName = engineImpl.overrideTelemetryName;
+    }
+  }
+
+  toJSON() {
+    let result = { name: this.overrideTelemetryName || this.name };
+    let properties = [
+      "took",
+      "status",
+      "failureReason",
+      "incoming",
+      "outgoing",
+      "validation",
+      "steps",
+    ];
+    for (let property of properties) {
+      result[property] = this[property];
+    }
+    return result;
+  }
+
+  finished(error) {
+    let took = timeDeltaFrom(this.startTime);
+    if (took > 0) {
+      this.took = took;
+    }
+    if (error) {
+      this.failureReason = SyncTelemetry.transformError(error);
+    }
+  }
+
+  recordApplied(counts) {
+    if (this.incoming) {
+      log.error(
+        `Incoming records applied multiple times for engine ${this.name}!`
+      );
+      return;
+    }
+    if (this.name === "clients" && !counts.failed) {
+      // ignore successful application of client records
+      // since otherwise they show up every time and are meaningless.
+      return;
+    }
+
+    let incomingData = {};
+
+    if (counts.failedReasons) {
+      // sort the failed reasons in desc by count, then take top 10
+      counts.failedReasons = counts.failedReasons
+        .sort((a, b) => b.count - a.count)
+        .slice(0, 10);
+    }
+    // Counts has extra stuff used for logging, but we only care about a few
+    let properties = ["applied", "failed", "failedReasons"];
+    // Only record non-zero properties and only record incoming at all if
+    // there's at least one property we care about.
+    for (let property of properties) {
+      if (counts[property]) {
+        incomingData[property] = counts[property];
+        this.incoming = incomingData;
+      }
+    }
+  }
+
+  recordStep(stepResult) {
+    let step = {
+      name: stepResult.name,
+    };
+    if (stepResult.took > 0) {
+      step.took = Math.round(stepResult.took);
+    }
+    if (stepResult.counts) {
+      let counts = stepResult.counts.filter(({ count }) => count > 0);
+      if (counts.length) {
+        step.counts = counts;
+      }
+    }
+    if (this.steps) {
+      this.steps.push(step);
+    } else {
+      this.steps = [step];
+    }
+  }
+
+  recordValidation(validationResult) {
+    if (this.validation) {
+      log.error(`Multiple validations occurred for engine ${this.name}!`);
+      return;
+    }
+    let { problems, version, took, checked } = validationResult;
+    let validation = {
+      version: version || 0,
+      checked: checked || 0,
+    };
+    if (took > 0) {
+      validation.took = Math.round(took);
+    }
+    let summarized = problems.filter(({ count }) => count > 0);
+    if (summarized.length) {
+      validation.problems = summarized;
+    }
+    this.validation = validation;
+  }
+
+  recordValidationError(e) {
+    if (this.validation) {
+      log.error(`Multiple validations occurred for engine ${this.name}!`);
+      return;
+    }
+
+    this.validation = {
+      failureReason: SyncTelemetry.transformError(e),
+    };
+  }
+
+  recordUploaded(counts) {
+    if (counts.sent || counts.failed) {
+      if (!this.outgoing) {
+        this.outgoing = [];
+      }
+      if (counts.failedReasons) {
+        // sort the failed reasons in desc by count, then take top 10
+        counts.failedReasons = counts.failedReasons
+          .sort((a, b) => b.count - a.count)
+          .slice(0, 10);
+      }
+      this.outgoing.push({
+        sent: counts.sent || undefined,
+        failed: counts.failed || undefined,
+        failedReasons: counts.failedReasons || undefined,
+      });
+    }
+  }
+}
+
+// The record of a single "sync" - typically many of these are submitted in
+// a single ping (ie, as a 'syncs' array)
+export class SyncRecord {
+  constructor(allowedEngines, why) {
+    this.allowedEngines = allowedEngines;
+    // Our failure reason. This property only exists in the generated ping if an
+    // error actually occurred.
+    this.failureReason = undefined;
+    this.syncNodeType = null;
+    this.when = Date.now();
+    this.startTime = tryGetMonotonicTimestamp();
+    this.took = 0; // will be set later.
+    this.why = why;
+
+    // All engines that have finished (ie, does not include the "current" one)
+    // We omit this from the ping if it's empty.
+    this.engines = [];
+    // The engine that has started but not yet stopped.
+    this.currentEngine = null;
+  }
+
+  toJSON() {
+    let result = {
+      when: this.when,
+      took: this.took,
+      failureReason: this.failureReason,
+      status: this.status,
+    };
+    if (this.why) {
+      result.why = this.why;
+    }
+    let engines = [];
+    for (let engine of this.engines) {
+      engines.push(engine.toJSON());
+    }
+    if (engines.length) {
+      result.engines = engines;
+    }
+    return result;
+  }
+
+  finished(error) {
+    this.took = timeDeltaFrom(this.startTime);
+    if (this.currentEngine != null) {
+      log.error(
+        "Finished called for the sync before the current engine finished"
+      );
+      this.currentEngine.finished(null);
+      this.onEngineStop(this.currentEngine.name);
+    }
+    if (error) {
+      this.failureReason = SyncTelemetry.transformError(error);
+    }
+
+    this.syncNodeType = lazy.Weave.Service.identity.telemetryNodeType;
+
+    // Check for engine statuses. -- We do this now, and not in engine.finished
+    // to make sure any statuses that get set "late" are recorded
+    for (let engine of this.engines) {
+      let status = lazy.Status.engines[engine.name];
+      if (status && status !== constants.ENGINE_SUCCEEDED) {
+        engine.status = status;
+      }
+    }
+
+    let statusObject = {};
+
+    let serviceStatus = lazy.Status.service;
+    if (serviceStatus && serviceStatus !== constants.STATUS_OK) {
+      statusObject.service = serviceStatus;
+      this.status = statusObject;
+    }
+    let syncStatus = lazy.Status.sync;
+    if (syncStatus && syncStatus !== constants.SYNC_SUCCEEDED) {
+      statusObject.sync = syncStatus;
+      this.status = statusObject;
+    }
+  }
+
+  onEngineStart(engineName) {
+    if (this._shouldIgnoreEngine(engineName, false)) {
+      return;
+    }
+
+    if (this.currentEngine) {
+      log.error(
+        `Being told that engine ${engineName} has started, but current engine ${this.currentEngine.name} hasn't stopped`
+      );
+      // Just discard the current engine rather than making up data for it.
+    }
+    this.currentEngine = new EngineRecord(engineName);
+  }
+
+  onEngineStop(engineName, error) {
+    // We only care if it's the current engine if we have a current engine.
+    if (this._shouldIgnoreEngine(engineName, !!this.currentEngine)) {
+      return;
+    }
+    if (!this.currentEngine) {
+      // It's possible for us to get an error before the start message of an engine
+      // (somehow), in which case we still want to record that error.
+      if (!error) {
+        return;
+      }
+      log.error(
+        `Error triggered on ${engineName} when no current engine exists: ${error}`
+      );
+      this.currentEngine = new EngineRecord(engineName);
+    }
+    this.currentEngine.finished(error);
+    this.engines.push(this.currentEngine);
+    this.currentEngine = null;
+  }
+
+  onEngineApplied(engineName, counts) {
+    if (this._shouldIgnoreEngine(engineName)) {
+      return;
+    }
+    this.currentEngine.recordApplied(counts);
+  }
+
+  onEngineStep(engineName, step) {
+    if (this._shouldIgnoreEngine(engineName)) {
+      return;
+    }
+    this.currentEngine.recordStep(step);
+  }
+
+  onEngineValidated(engineName, validationData) {
+    if (this._shouldIgnoreEngine(engineName, false)) {
+      return;
+    }
+    let engine = this.engines.find(e => e.name === engineName);
+    if (
+      !engine &&
+      this.currentEngine &&
+      engineName === this.currentEngine.name
+    ) {
+      engine = this.currentEngine;
+    }
+    if (engine) {
+      engine.recordValidation(validationData);
+    } else {
+      log.warn(
+        `Validation event triggered for engine ${engineName}, which hasn't been synced!`
+      );
+    }
+  }
+
+  onEngineValidateError(engineName, error) {
+    if (this._shouldIgnoreEngine(engineName, false)) {
+      return;
+    }
+    let engine = this.engines.find(e => e.name === engineName);
+    if (
+      !engine &&
+      this.currentEngine &&
+      engineName === this.currentEngine.name
+    ) {
+      engine = this.currentEngine;
+    }
+    if (engine) {
+      engine.recordValidationError(error);
+    } else {
+      log.warn(
+        `Validation failure event triggered for engine ${engineName}, which hasn't been synced!`
+      );
+    }
+  }
+
+  onEngineUploaded(engineName, counts) {
+    if (this._shouldIgnoreEngine(engineName)) {
+      return;
+    }
+    this.currentEngine.recordUploaded(counts);
+  }
+
+  _shouldIgnoreEngine(engineName, shouldBeCurrent = true) {
+    if (!this.allowedEngines.has(engineName)) {
+      log.info(
+        `Notification for engine ${engineName}, but we aren't recording telemetry for it`
+      );
+      return true;
+    }
+    if (shouldBeCurrent) {
+      if (!this.currentEngine || engineName != this.currentEngine.name) {
+        log.info(`Notification for engine ${engineName} but it isn't current`);
+        return true;
+      }
+    }
+    return false;
+  }
+}
+
+// The entire "sync ping" - it includes all the syncs, events etc recorded in
+// the ping.
+class SyncTelemetryImpl {
+  constructor(allowedEngines) {
+    log.manageLevelFromPref("services.sync.log.logger.telemetry");
+    // This is accessible so we can enable custom engines during tests.
+    this.allowedEngines = allowedEngines;
+    this.current = null;
+    this.setupObservers();
+
+    this.payloads = [];
+    this.discarded = 0;
+    this.events = [];
+    this.histograms = {};
+    this.migrations = [];
+    this.maxEventsCount = lazy.Svc.Prefs.get("telemetry.maxEventsCount", 1000);
+    this.maxPayloadCount = lazy.Svc.Prefs.get("telemetry.maxPayloadCount");
+    this.submissionInterval =
+      lazy.Svc.Prefs.get("telemetry.submissionInterval") * 1000;
+    this.lastSubmissionTime = Services.telemetry.msSinceProcessStart();
+    this.lastUID = EMPTY_UID;
+    this.lastSyncNodeType = null;
+    this.currentSyncNodeType = null;
+    // Note that the sessionStartDate is somewhat arbitrary - the telemetry
+    // modules themselves just use `new Date()`. This means that our startDate
+    // isn't going to be the same as the sessionStartDate in the main pings,
+    // but that's OK for now - if it's a problem we'd need to change the
+    // telemetry modules to expose what it thinks the sessionStartDate is.
+    let sessionStartDate = new Date();
+    this.sessionStartDate = lazy.TelemetryUtils.toLocalTimeISOString(
+      lazy.TelemetryUtils.truncateToHours(sessionStartDate)
+    );
+    lazy.TelemetryController.registerSyncPingShutdown(() => this.shutdown());
+  }
+
+  sanitizeFxaDeviceId(deviceId) {
+    return lazy.fxAccounts.telemetry.sanitizeDeviceId(deviceId);
+  }
+
+  prepareFxaDevices(devices) {
+    // For non-sync users, the data per device is limited -- just an id and a
+    // type (and not even the id yet). For sync users, if we can correctly map
+    // the fxaDevice to a sync device, then we can get os and version info,
+    // which would be quite unfortunate to lose.
+    let extraInfoMap = new Map();
+    if (this.syncIsEnabled()) {
+      for (let client of this.getClientsEngineRecords()) {
+        if (client.fxaDeviceId) {
+          extraInfoMap.set(client.fxaDeviceId, {
+            os: client.os,
+            version: client.version,
+            syncID: this.sanitizeFxaDeviceId(client.id),
+          });
+        }
+      }
+    }
+    // Finally, sanitize and convert to the proper format.
+    return devices.map(d => {
+      let { os, version, syncID } = extraInfoMap.get(d.id) || {
+        os: undefined,
+        version: undefined,
+        syncID: undefined,
+      };
+      return {
+        id: this.sanitizeFxaDeviceId(d.id) || EMPTY_UID,
+        type: d.type,
+        os,
+        version,
+        syncID,
+      };
+    });
+  }
+
+  syncIsEnabled() {
+    return lazy.WeaveService.enabled && lazy.WeaveService.ready;
+  }
+
+  // Separate for testing.
+  getClientsEngineRecords() {
+    if (!this.syncIsEnabled()) {
+      throw new Error("Bug: syncIsEnabled() must be true, check it first");
+    }
+    return lazy.Weave.Service.clientsEngine.remoteClients;
+  }
+
+  updateFxaDevices(devices) {
+    if (!devices) {
+      return {};
+    }
+    let me = devices.find(d => d.isCurrentDevice);
+    let id = me ? this.sanitizeFxaDeviceId(me.id) : undefined;
+    let cleanDevices = this.prepareFxaDevices(devices);
+    return { deviceID: id, devices: cleanDevices };
+  }
+
+  getFxaDevices() {
+    return lazy.fxAccounts.device.recentDeviceList;
+  }
+
+  getPingJSON(reason) {
+    let { devices, deviceID } = this.updateFxaDevices(this.getFxaDevices());
+    return {
+      os: lazy.TelemetryEnvironment.currentEnvironment.system.os,
+      why: reason,
+      devices,
+      discarded: this.discarded || undefined,
+      version: PING_FORMAT_VERSION,
+      syncs: this.payloads.slice(),
+      uid: this.lastUID,
+      syncNodeType: this.lastSyncNodeType || undefined,
+      deviceID,
+      sessionStartDate: this.sessionStartDate,
+      events: !this.events.length ? undefined : this.events,
+      migrations: !this.migrations.length ? undefined : this.migrations,
+      histograms: !Object.keys(this.histograms).length
+        ? undefined
+        : this.histograms,
+    };
+  }
+
+  _addMigrationRecord(type, info) {
+    log.debug("Saw telemetry migration info", type, info);
+    // Updates to this need to be documented in `sync-ping.rst`
+    switch (type) {
+      case "webext-storage":
+        this.migrations.push({
+          type: "webext-storage",
+          entries: +info.entries,
+          entriesSuccessful: +info.entries_successful,
+          extensions: +info.extensions,
+          extensionsSuccessful: +info.extensions_successful,
+          openFailure: !!info.open_failure,
+        });
+        break;
+      default:
+        throw new Error("Bug: Unknown migration record type " + type);
+    }
+  }
+
+  finish(reason) {
+    // Note that we might be in the middle of a sync right now, and so we don't
+    // want to touch this.current.
+    let result = this.getPingJSON(reason);
+    this.payloads = [];
+    this.discarded = 0;
+    this.events = [];
+    this.migrations = [];
+    this.histograms = {};
+    this.submit(result);
+  }
+
+  setupObservers() {
+    for (let topic of TOPICS) {
+      lazy.Observers.add(topic, this, this);
+    }
+  }
+
+  shutdown() {
+    this.finish("shutdown");
+    for (let topic of TOPICS) {
+      lazy.Observers.remove(topic, this, this);
+    }
+  }
+
+  submit(record) {
+    if (!this.isProductionSyncUser()) {
+      return false;
+    }
+    // We still call submit() with possibly illegal payloads so that tests can
+    // know that the ping was built. We don't end up submitting them, however.
+    let numEvents = record.events ? record.events.length : 0;
+    let numMigrations = record.migrations ? record.migrations.length : 0;
+    if (record.syncs.length || numEvents || numMigrations) {
+      log.trace(
+        `submitting ${record.syncs.length} sync record(s) and ` +
+          `${numEvents} event(s) to telemetry`
+      );
+      lazy.TelemetryController.submitExternalPing("sync", record, {
+        usePingSender: true,
+      }).catch(err => {
+        log.error("failed to submit ping", err);
+      });
+      return true;
+    }
+    return false;
+  }
+
+  isProductionSyncUser() {
+    // If FxA isn't production then we treat sync as not being production.
+    // Further, there's the deprecated "services.sync.tokenServerURI" pref we
+    // need to consider - fxa doesn't consider that as if that's the only
+    // pref set, they *are* running a production fxa, just not production sync.
+    if (
+      !lazy.FxAccounts.config.isProductionConfig() ||
+      Services.prefs.prefHasUserValue("services.sync.tokenServerURI")
+    ) {
+      log.trace(`Not sending telemetry ping for self-hosted Sync user`);
+      return false;
+    }
+    return true;
+  }
+
+  onSyncStarted(data) {
+    const why = data && JSON.parse(data).why;
+    if (this.current) {
+      log.warn(
+        "Observed weave:service:sync:start, but we're already recording a sync!"
+      );
+      // Just discard the old record, consistent with our handling of engines, above.
+      this.current = null;
+    }
+    this.current = new SyncRecord(this.allowedEngines, why);
+  }
+
+  // We need to ensure that the telemetry `deletion-request` ping always contains the user's
+  // current sync device ID, because if the user opts out of telemetry then the deletion ping
+  // will be immediately triggered for sending, and we won't have a chance to fill it in later.
+  // This keeps the `deletion-ping` up-to-date when the user's account state changes.
+  onAccountInitOrChange() {
+    // We don't submit sync pings for self-hosters, so don't need to collect their device ids either.
+    if (!this.isProductionSyncUser()) {
+      return;
+    }
+    // Awkwardly async, but no need to await. If the user's account state changes while
+    // this promise is in flight, it will reject and we won't record any data in the ping.
+    // (And a new notification will trigger us to try again with the new state).
+    lazy.fxAccounts.device
+      .getLocalId()
+      .then(deviceId => {
+        let sanitizedDeviceId =
+          lazy.fxAccounts.telemetry.sanitizeDeviceId(deviceId);
+        // In the past we did not persist the FxA metrics identifiers to disk,
+        // so this might be missing until we can fetch it from the server for the
+        // first time. There will be a fresh notification tirggered when it's available.
+        if (sanitizedDeviceId) {
+          // Sanitized device ids are 64 characters long, but telemetry limits scalar strings to 50.
+          // The first 32 chars are sufficient to uniquely identify the device, so just send those.
+          // It's hard to change the sync ping itself to only send 32 chars, to b/w compat reasons.
+          sanitizedDeviceId = sanitizedDeviceId.substr(0, 32);
+          Services.telemetry.scalarSet(
+            "deletion.request.sync_device_id",
+            sanitizedDeviceId
+          );
+        }
+      })
+      .catch(err => {
+        log.warn(
+          `Failed to set sync identifiers in the deletion-request ping: ${err}`
+        );
+      });
+  }
+
+  // This keeps the `deletion-request` ping up-to-date when the user signs out,
+  // clearing the now-nonexistent sync device id.
+  onAccountLogout() {
+    Services.telemetry.scalarSet("deletion.request.sync_device_id", "");
+  }
+
+  _checkCurrent(topic) {
+    if (!this.current) {
+      // This is only `info` because it happens when we do a tabs "quick-write"
+      log.info(
+        `Observed notification ${topic} but no current sync is being recorded.`
+      );
+      return false;
+    }
+    return true;
+  }
+
+  _shouldSubmitForDataChange() {
+    let newID = lazy.fxAccounts.telemetry.getSanitizedUID() || EMPTY_UID;
+    let oldID = this.lastUID;
+    if (
+      newID != EMPTY_UID &&
+      oldID != EMPTY_UID &&
+      // Both are "real" uids, so we care if they've changed.
+      newID != oldID
+    ) {
+      log.trace(
+        `shouldSubmitForDataChange - uid from '${oldID}' -> '${newID}'`
+      );
+      return true;
+    }
+    // We've gone from knowing one of the ids to not knowing it (which we
+    // ignore) or we've gone from not knowing it to knowing it (which is fine),
+    // Now check the node type because a change there also means we should
+    // submit.
+    if (
+      this.lastSyncNodeType &&
+      this.currentSyncNodeType != this.lastSyncNodeType
+    ) {
+      log.trace(
+        `shouldSubmitForDataChange - nodeType from '${this.lastSyncNodeType}' -> '${this.currentSyncNodeType}'`
+      );
+      return true;
+    }
+    log.trace("shouldSubmitForDataChange - no need to submit");
+    return false;
+  }
+
+  maybeSubmitForDataChange() {
+    if (this._shouldSubmitForDataChange()) {
+      log.info(
+        "Early submission of sync telemetry due to changed IDs/NodeType"
+      );
+      this.finish("idchange"); // this actually submits.
+      this.lastSubmissionTime = Services.telemetry.msSinceProcessStart();
+    }
+
+    // Only update the last UIDs if we actually know them.
+    let current_uid = lazy.fxAccounts.telemetry.getSanitizedUID();
+    if (current_uid) {
+      this.lastUID = current_uid;
+    }
+    if (this.currentSyncNodeType) {
+      this.lastSyncNodeType = this.currentSyncNodeType;
+    }
+  }
+
+  maybeSubmitForInterval() {
+    // We want to submit the ping every `this.submissionInterval` but only when
+    // there's no current sync in progress, otherwise we may end up submitting
+    // the sync and the events caused by it in different pings.
+    if (
+      this.current == null &&
+      Services.telemetry.msSinceProcessStart() - this.lastSubmissionTime >
+        this.submissionInterval
+    ) {
+      this.finish("schedule");
+      this.lastSubmissionTime = Services.telemetry.msSinceProcessStart();
+    }
+  }
+
+  onSyncFinished(error) {
+    if (!this.current) {
+      log.warn("onSyncFinished but we aren't recording");
+      return;
+    }
+    this.current.finished(error);
+    this.currentSyncNodeType = this.current.syncNodeType;
+    let current = this.current;
+    this.current = null;
+    this.takeTelemetryRecord(current);
+  }
+
+  takeTelemetryRecord(record) {
+    // We check for "data change" before appending the current sync to payloads,
+    // as it is the current sync which has the data with the new data, and thus
+    // must go in the *next* submission.
+    this.maybeSubmitForDataChange();
+    if (this.payloads.length < this.maxPayloadCount) {
+      this.payloads.push(record.toJSON());
+    } else {
+      ++this.discarded;
+    }
+    // If we are submitting due to timing, it's desirable that the most recent
+    // sync is included, so we check after appending the record.
+    this.maybeSubmitForInterval();
+  }
+
+  _addHistogram(hist) {
+    let histogram = Services.telemetry.getHistogramById(hist);
+    let s = histogram.snapshot();
+    this.histograms[hist] = s;
+  }
+
+  _recordEvent(eventDetails) {
+    this.maybeSubmitForDataChange();
+
+    if (this.events.length >= this.maxEventsCount) {
+      log.warn("discarding event - already queued our maximum", eventDetails);
+      return;
+    }
+
+    let { object, method, value, extra } = eventDetails;
+    if (extra) {
+      extra = normalizeExtraTelemetryFields(extra);
+      eventDetails = { object, method, value, extra };
+    }
+
+    if (!validateTelemetryEvent(eventDetails)) {
+      // we've already logged what the problem is...
+      return;
+    }
+    log.debug("recording event", eventDetails);
+
+    if (extra && lazy.Resource.serverTime && !extra.serverTime) {
+      extra.serverTime = String(lazy.Resource.serverTime);
+    }
+    let category = "sync";
+    let ts = Math.floor(tryGetMonotonicTimestamp());
+
+    // An event record is a simple array with at least 4 items.
+    let event = [ts, category, method, object];
+    // It may have up to 6 elements if |extra| is defined
+    if (value) {
+      event.push(value);
+      if (extra) {
+        event.push(extra);
+      }
+    } else if (extra) {
+      event.push(null); // a null for the empty value.
+      event.push(extra);
+    }
+    this.events.push(event);
+    this.maybeSubmitForInterval();
+  }
+
+  observe(subject, topic, data) {
+    log.trace(`observed ${topic} ${data}`);
+
+    switch (topic) {
+      case "weave:service:ready":
+      case "weave:service:login:got-hashed-id":
+      case "fxaccounts:new_device_id":
+        this.onAccountInitOrChange();
+        break;
+
+      case "fxaccounts:onlogout":
+        this.onAccountLogout();
+        break;
+
+      /* sync itself state changes */
+      case "weave:service:sync:start":
+        this.onSyncStarted(data);
+        break;
+
+      case "weave:service:sync:finish":
+        if (this._checkCurrent(topic)) {
+          this.onSyncFinished(null);
+        }
+        break;
+
+      case "weave:service:sync:error":
+        // argument needs to be truthy (this should always be the case)
+        this.onSyncFinished(subject || "Unknown");
+        break;
+
+      /* engine sync state changes */
+      case "weave:engine:sync:start":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineStart(data);
+        }
+        break;
+      case "weave:engine:sync:finish":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineStop(data, null);
+        }
+        break;
+
+      case "weave:engine:sync:error":
+        if (this._checkCurrent(topic)) {
+          // argument needs to be truthy (this should always be the case)
+          this.current.onEngineStop(data, subject || "Unknown");
+        }
+        break;
+
+      /* engine counts */
+      case "weave:engine:sync:applied":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineApplied(data, subject);
+        }
+        break;
+
+      case "weave:engine:sync:step":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineStep(data, subject);
+        }
+        break;
+
+      case "weave:engine:sync:uploaded":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineUploaded(data, subject);
+        }
+        break;
+
+      case "weave:engine:validate:finish":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineValidated(data, subject);
+        }
+        break;
+
+      case "weave:engine:validate:error":
+        if (this._checkCurrent(topic)) {
+          this.current.onEngineValidateError(data, subject || "Unknown");
+        }
+        break;
+
+      case "weave:telemetry:event":
+      case "fxa:telemetry:event":
+        this._recordEvent(subject);
+        break;
+
+      case "weave:telemetry:histogram":
+        this._addHistogram(data);
+        break;
+
+      case "weave:telemetry:migration":
+        this._addMigrationRecord(data, subject);
+        break;
+
+      default:
+        log.warn(`unexpected observer topic ${topic}`);
+        break;
+    }
+  }
+
+  // Transform an exception into a standard description. Exposed here for when
+  // this module isn't directly responsible for knowing the transform should
+  // happen (for example, when including an error in the |extra| field of
+  // event telemetry)
+  transformError(error) {
+    // Certain parts of sync will use this pattern as a way to communicate to
+    // processIncoming to abort the processing. However, there's no guarantee
+    // this can only happen then.
+    if (typeof error == "object" && error.code && error.cause) {
+      error = error.cause;
+    }
+    if (lazy.Async.isShutdownException(error)) {
+      return { name: "shutdownerror" };
+    }
+
+    if (typeof error === "string") {
+      if (error.startsWith("error.")) {
+        // This is hacky, but I can't imagine that it's not also accurate.
+        return { name: "othererror", error };
+      }
+      error = ErrorSanitizer.cleanErrorMessage(error);
+      return { name: "unexpectederror", error };
+    }
+
+    if (error instanceof lazy.AuthenticationError) {
+      return { name: "autherror", from: error.source };
+    }
+
+    if (DOMException.isInstance(error)) {
+      return {
+        name: "unexpectederror",
+        error: ErrorSanitizer.cleanErrorMessage(error.message, error),
+      };
+    }
+
+    let httpCode =
+      error.status || (error.response && error.response.status) || error.code;
+
+    if (httpCode) {
+      return { name: "httperror", code: httpCode };
+    }
+
+    if (error.failureCode) {
+      return { name: "othererror", error: error.failureCode };
+    }
+
+    if (error.result) {
+      // many "nsresult" errors are actually network errors - if they are
+      // associated with the "network" module we assume that's true.
+      // We also assume NS_ERROR_ABORT is such an error - for almost everything
+      // we care about, it acually is (eg, if the connection fails early enough
+      // or if we have a captive portal etc) - we don't lose anything by this
+      // assumption, it's just that the error will no longer be in the "nserror"
+      // category, so our analysis can still find them.
+      if (
+        error.result == Cr.NS_ERROR_ABORT ||
+        NS_ERROR_GET_MODULE(error.result) == NS_ERROR_MODULE_NETWORK
+      ) {
+        return { name: "httperror", code: error.result };
+      }
+      return { name: "nserror", code: error.result };
+    }
+    // It's probably an Error object, but it also could be some
+    // other object that may or may not override toString to do
+    // something useful.
+    let msg = String(error);
+    if (msg.startsWith("[object")) {
+      // Nothing useful in the default, check for a string "message" property.
+      if (typeof error.message == "string") {
+        msg = String(error.message);
+      } else {
+        // Hopefully it won't come to this...
+        msg = JSON.stringify(error);
+      }
+    }
+    return {
+      name: "unexpectederror",
+      error: ErrorSanitizer.cleanErrorMessage(msg),
+    };
+  }
+}
+
+export var SyncTelemetry = new SyncTelemetryImpl(ENGINES);