Bug 841028: Add last build ID to telemetry system info if build ID has changed. r=froydnj

toolkit/components/telemetry/TelemetryPing.js

@@ -23,12 +23,15 @@ const PAYLOAD_VERSION = 1;
 // submitted ping data with its histogram definition (bug 832007)
 #expand const HISTOGRAMS_FILE_VERSION = "__HISTOGRAMS_FILE_VERSION__";
 
-const PREF_SERVER = "toolkit.telemetry.server";
+const PREF_BRANCH = "toolkit.telemetry.";
+const PREF_SERVER = PREF_BRANCH + "server";
 #ifdef MOZ_TELEMETRY_ON_BY_DEFAULT
-const PREF_ENABLED = "toolkit.telemetry.enabledPreRelease";
+const PREF_ENABLED = PREF_BRANCH + "enabledPreRelease";
 #else
-const PREF_ENABLED = "toolkit.telemetry.enabled";
+const PREF_ENABLED = PREF_BRANCH + "enabled";
 #endif
+const PREF_PREVIOUS_BUILDID = PREF_BRANCH + "previousBuildID";
+
 // Do not gather data more than once a minute
 const TELEMETRY_INTERVAL = 60000;
 // Delay before intializing telemetry (ms)
@@ -182,6 +185,9 @@ TelemetryPing.prototype = {
   // handles retrieving histograms and writing the data to disk.
   _savedSimpleMeasurements: null,
   _savedInfo: null,
+  // The previous build ID, if this is the first run with a new build.
+  // Undefined if this is not the first run, or the previous build ID is unknown.
+  _previousBuildID: undefined,
 
   /**
    * Gets a series of simple measurements (counters). At the moment, this
@@ -385,6 +391,9 @@ TelemetryPing.prototype = {
       revision: HISTOGRAMS_FILE_VERSION,
       locale: getLocale()
     };
+    if (this._previousBuildID) {
+      ret.previousBuildID = this._previousBuildID;
+    }
 
     // sysinfo fields are not always available, get what we can.
     let sysInfo = Cc["@mozilla.org/system-info;1"].getService(Ci.nsIPropertyBag2);
@@ -753,6 +762,22 @@ TelemetryPing.prototype = {
    * Initializes telemetry within a timer. If there is no PREF_SERVER set, don't turn on telemetry.
    */
   setup: function setup() {
+    // Record old value and update build ID preference if this is the first
+    // run with a new build ID.
+    let previousBuildID = undefined;
+    try {
+      previousBuildID = Services.prefs.getCharPref(PREF_PREVIOUS_BUILDID);
+    } catch (e) {
+      // Preference was not set.
+    }
+    let thisBuildID = Services.appinfo.appBuildID;
+    // If there is no previousBuildID preference, this._previousBuildID remains
+    // undefined so no value is sent in the telemetry metadata.
+    if (previousBuildID != thisBuildID) {
+      this._previousBuildID = previousBuildID;
+      Services.prefs.setCharPref(PREF_PREVIOUS_BUILDID, thisBuildID);
+    }
+
 #ifdef MOZILLA_OFFICIAL
     if (!Telemetry.canSend) {
       // We can't send data; no point in initializing observers etc.

toolkit/components/telemetry/tests/unit/test_TelemetryPingBuildID.js

@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/
+*/
+/* Test inclusion of previous build ID in telemetry pings when build ID changes.
+ * bug 841028
+ *
+ * Cases to cover:
+ * 1) Run with no "previousBuildID" stored in prefs:
+ *     -> no previousBuildID in telemetry system info, new value set in prefs.
+ * 2) previousBuildID in prefs, equal to current build ID:
+ *     -> no previousBuildID in telemetry, prefs not updated.
+ * 3) previousBuildID in prefs, not equal to current build ID:
+ *     -> previousBuildID in telemetry, new value set in prefs.
+ */
+
+Components.utils.import("resource://gre/modules/Services.jsm");
+
+// Get the TelemetryPing definitions directly so we can test it without going through xpcom.
+Services.scriptloader.loadSubScript("resource://gre/components/TelemetryPing.js");
+
+// Force the Telemetry enabled preference so that TelemetryPing.setup() doesn't exit early.
+Services.prefs.setBoolPref(PREF_ENABLED, true);
+
+// Set up our dummy AppInfo object so we can control the appBuildID.
+Cu.import("resource://testing-common/AppInfo.jsm");
+updateAppInfo();
+
+// Check that when run with no previous build ID stored, we update the pref but do not
+// put anything into the metadata.
+function testFirstRun() {
+  let ping = new TelemetryPing();
+  ping.setup();
+  let metadata = ping.getMetadata();
+  do_check_false("previousBuildID" in metadata);
+  let appBuildID = getAppInfo().appBuildID;
+  let buildIDPref = Services.prefs.getCharPref(PREF_PREVIOUS_BUILDID);
+  do_check_eq(appBuildID, buildIDPref);
+}
+
+// Check that a subsequent run with the same build ID does not put prev build ID in
+// metadata. Assumes testFirstRun() has already been called to set the previousBuildID pref.
+function testSecondRun() {
+  let ping = new TelemetryPing();
+  ping.setup();
+  let metadata = ping.getMetadata();
+  do_check_false("previousBuildID" in metadata);
+}
+
+
+// Set up telemetry with a different app build ID and check that the old build ID
+// is returned in the metadata and the pref is updated to the new build ID.
+// Assumes testFirstRun() has been called to set the previousBuildID pref.
+const NEW_BUILD_ID = "20130314";
+function testNewBuild() {
+  let info = getAppInfo();
+  let oldBuildID = info.appBuildID;
+  info.appBuildID = NEW_BUILD_ID;
+  let ping = new TelemetryPing();
+  ping.setup();
+  let metadata = ping.getMetadata();
+  do_check_eq(metadata.previousBuildID, oldBuildID);
+  let buildIDPref = Services.prefs.getCharPref(PREF_PREVIOUS_BUILDID);
+  do_check_eq(NEW_BUILD_ID, buildIDPref);
+}
+
+
+function run_test() {
+  // Make sure we have a profile directory.
+  do_get_profile();
+  testFirstRun();
+  testSecondRun();
+  testNewBuild();
+}

toolkit/components/telemetry/tests/unit/xpcshell.ini

@@ -8,3 +8,4 @@ tail =
 # fail-if = os == "android"
 [test_TelemetryPing_idle.js]
 [test_TelemetryStopwatch.js]
+[test_TelemetryPingBuildID.js]