1 files changed, 241 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/pings/EventPing.sys.mjs b/toolkit/components/telemetry/pings/EventPing.sys.mjs
new file mode 100644
index 0000000000..36e8489e37
--- /dev/null
+++ b/toolkit/components/telemetry/pings/EventPing.sys.mjs
@@ -0,0 +1,241 @@
+/* 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/. */
+
+/*
+ * This module sends Telemetry Events periodically:
+ * https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/telemetry/data/event-ping.html
+ */
+
+import { TelemetryUtils } from "resource://gre/modules/TelemetryUtils.sys.mjs";
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  Log: "resource://gre/modules/Log.sys.mjs",
+  TelemetryController: "resource://gre/modules/TelemetryController.sys.mjs",
+  TelemetrySession: "resource://gre/modules/TelemetrySession.sys.mjs",
+  clearTimeout: "resource://gre/modules/Timer.sys.mjs",
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+});
+
+const Utils = TelemetryUtils;
+
+const MS_IN_A_MINUTE = 60 * 1000;
+
+const DEFAULT_EVENT_LIMIT = 1000;
+const DEFAULT_MIN_FREQUENCY_MS = 60 * MS_IN_A_MINUTE;
+const DEFAULT_MAX_FREQUENCY_MS = 10 * MS_IN_A_MINUTE;
+
+const LOGGER_NAME = "Toolkit.Telemetry";
+const LOGGER_PREFIX = "TelemetryEventPing::";
+
+const EVENT_LIMIT_REACHED_TOPIC = "event-telemetry-storage-limit-reached";
+
+export var Policy = {
+  setTimeout: (callback, delayMs) => lazy.setTimeout(callback, delayMs),
+  clearTimeout: id => lazy.clearTimeout(id),
+  sendPing: (type, payload, options) =>
+    lazy.TelemetryController.submitExternalPing(type, payload, options),
+};
+
+export var TelemetryEventPing = {
+  Reason: Object.freeze({
+    PERIODIC: "periodic", // Sent the ping containing events from the past periodic interval (default one hour).
+    MAX: "max", // Sent the ping containing the maximum number (default 1000) of event records, earlier than the periodic interval.
+    SHUTDOWN: "shutdown", // Recorded data was sent on shutdown.
+  }),
+
+  EVENT_PING_TYPE: "event",
+
+  _logger: null,
+
+  _testing: false,
+
+  // So that if we quickly reach the max limit we can immediately send.
+  _lastSendTime: -DEFAULT_MIN_FREQUENCY_MS,
+
+  _processStartTimestamp: 0,
+
+  get dataset() {
+    return Services.telemetry.canRecordPrereleaseData
+      ? Ci.nsITelemetry.DATASET_PRERELEASE_CHANNELS
+      : Ci.nsITelemetry.DATASET_ALL_CHANNELS;
+  },
+
+  startup() {
+    this._log.trace("Starting up.");
+
+    // Calculate process creation once.
+    this._processStartTimestamp =
+      Math.round(
+        (Date.now() - TelemetryUtils.monotonicNow()) / MS_IN_A_MINUTE
+      ) * MS_IN_A_MINUTE;
+
+    Services.obs.addObserver(this, EVENT_LIMIT_REACHED_TOPIC);
+
+    XPCOMUtils.defineLazyPreferenceGetter(
+      this,
+      "maxFrequency",
+      Utils.Preferences.EventPingMaximumFrequency,
+      DEFAULT_MAX_FREQUENCY_MS
+    );
+    XPCOMUtils.defineLazyPreferenceGetter(
+      this,
+      "minFrequency",
+      Utils.Preferences.EventPingMinimumFrequency,
+      DEFAULT_MIN_FREQUENCY_MS
+    );
+
+    this._startTimer();
+  },
+
+  shutdown() {
+    this._log.trace("Shutting down.");
+    // removeObserver may throw, which could interrupt shutdown.
+    try {
+      Services.obs.removeObserver(this, EVENT_LIMIT_REACHED_TOPIC);
+    } catch (ex) {}
+
+    this._submitPing(this.Reason.SHUTDOWN, true /* discardLeftovers */);
+    this._clearTimer();
+  },
+
+  observe(aSubject, aTopic, aData) {
+    switch (aTopic) {
+      case EVENT_LIMIT_REACHED_TOPIC:
+        this._log.trace("event limit reached");
+        let now = Utils.monotonicNow();
+        if (now - this._lastSendTime < this.maxFrequency) {
+          this._log.trace("can't submit ping immediately as it's too soon");
+          this._startTimer(
+            this.maxFrequency - this._lastSendTime,
+            this.Reason.MAX,
+            true /* discardLeftovers*/
+          );
+        } else {
+          this._log.trace("submitting ping immediately");
+          this._submitPing(this.Reason.MAX);
+        }
+        break;
+    }
+  },
+
+  _startTimer(
+    delay = this.minFrequency,
+    reason = this.Reason.PERIODIC,
+    discardLeftovers = false
+  ) {
+    this._clearTimer();
+    this._timeoutId = Policy.setTimeout(
+      () => TelemetryEventPing._submitPing(reason, discardLeftovers),
+      delay
+    );
+  },
+
+  _clearTimer() {
+    if (this._timeoutId) {
+      Policy.clearTimeout(this._timeoutId);
+      this._timeoutId = null;
+    }
+  },
+
+  /**
+   * Submits an "event" ping and restarts the timer for the next interval.
+   *
+   * @param {String} reason The reason we're sending the ping. One of TelemetryEventPing.Reason.
+   * @param {bool} discardLeftovers Whether to discard event records left over from a previous ping.
+   */
+  _submitPing(reason, discardLeftovers = false) {
+    this._log.trace("_submitPing");
+
+    if (reason !== this.Reason.SHUTDOWN) {
+      this._startTimer();
+    }
+
+    let snapshot = Services.telemetry.snapshotEvents(
+      this.dataset,
+      true /* clear */,
+      DEFAULT_EVENT_LIMIT
+    );
+
+    if (!this._testing) {
+      for (let process of Object.keys(snapshot)) {
+        snapshot[process] = snapshot[process].filter(
+          ([, category]) => !category.startsWith("telemetry.test")
+        );
+      }
+    }
+
+    let eventCount = Object.values(snapshot).reduce(
+      (acc, val) => acc + val.length,
+      0
+    );
+    if (eventCount === 0) {
+      // Don't send a ping if we haven't any events.
+      this._log.trace("not sending event ping due to lack of events");
+      return;
+    }
+
+    // The reason doesn't matter as it will just be echo'd back.
+    let sessionMeta = lazy.TelemetrySession.getMetadata(reason);
+
+    let payload = {
+      reason,
+      processStartTimestamp: this._processStartTimestamp,
+      sessionId: sessionMeta.sessionId,
+      subsessionId: sessionMeta.subsessionId,
+      lostEventsCount: 0,
+      events: snapshot,
+    };
+
+    if (discardLeftovers) {
+      // Any leftovers must be discarded, the count submitted in the ping.
+      // This can happen on shutdown or if our max was reached before faster
+      // than our maxFrequency.
+      let leftovers = Services.telemetry.snapshotEvents(
+        this.dataset,
+        true /* clear */
+      );
+      let leftoverCount = Object.values(leftovers).reduce(
+        (acc, val) => acc + val.length,
+        0
+      );
+      payload.lostEventsCount = leftoverCount;
+    }
+
+    const options = {
+      addClientId: true,
+      addEnvironment: true,
+      usePingSender: reason == this.Reason.SHUTDOWN,
+    };
+
+    this._lastSendTime = Utils.monotonicNow();
+    Services.telemetry
+      .getHistogramById("TELEMETRY_EVENT_PING_SENT")
+      .add(reason);
+    Policy.sendPing(this.EVENT_PING_TYPE, payload, options);
+  },
+
+  /**
+   * Test-only, restore to initial state.
+   */
+  testReset() {
+    this._lastSendTime = -DEFAULT_MIN_FREQUENCY_MS;
+    this._clearTimer();
+    this._testing = true;
+  },
+
+  get _log() {
+    if (!this._logger) {
+      this._logger = lazy.Log.repository.getLoggerWithMessagePrefix(
+        LOGGER_NAME,
+        LOGGER_PREFIX + "::"
+      );
+    }
+
+    return this._logger;
+  },
+};