Wait for a valid SessionID before logging the app start event.

firebase-perf/CHANGELOG.md

@@ -10,6 +10,7 @@
   now deprecated. As early as April 2024, we'll no longer release KTX modules. For details, see the
   [FAQ about this initiative](https://firebase.google.com/docs/android/kotlin-migration)
 
+* [changed] Ensure that AppStart trace contains a valid sessionID.
 
 # 20.4.1
 * [changed] Updated `firebase-sessions` dependency to v1.0.2

firebase-perf/src/main/java/com/google/firebase/perf/metrics/AppStartTrace.java

@@ -39,6 +39,7 @@
 import com.google.firebase.perf.config.ConfigResolver;
 import com.google.firebase.perf.logging.AndroidLogger;
 import com.google.firebase.perf.session.PerfSession;
+import com.google.firebase.perf.session.SessionAwareObject;
 import com.google.firebase.perf.session.SessionManager;
 import com.google.firebase.perf.transport.TransportManager;
 import com.google.firebase.perf.util.Clock;
@@ -70,7 +71,8 @@
  *
  * @hide
  */
-public class AppStartTrace implements ActivityLifecycleCallbacks, LifecycleObserver {
+public class AppStartTrace
+    implements ActivityLifecycleCallbacks, LifecycleObserver, SessionAwareObject {
 
   private static final @NonNull Timer PERF_CLASS_LOAD_TIME = new Clock().getTime();
   private static final long MAX_LATENCY_BEFORE_UI_INIT = TimeUnit.MINUTES.toMicros(1);
@@ -97,6 +99,9 @@ public class AppStartTrace implements ActivityLifecycleCallbacks, LifecycleObser
    */
   private WeakReference<Activity> appStartActivity;
 
+  // Start tracking session information changes for app start trace.
+  private final WeakReference<SessionAwareObject> sessionAwareObject = new WeakReference<>(this);
+
   /**
    * If the time difference between app starts and creation of any Activity is larger than
    * MAX_LATENCY_BEFORE_UI_INIT, set mTooLateToInitUI to true and we don't send AppStart Trace.
@@ -365,7 +370,14 @@ public synchronized void onActivityResumed(Activity activity) {
     appStartActivity = new WeakReference<Activity>(activity);
 
     onResumeTime = clock.getTime();
-    this.startSession = SessionManager.getInstance().perfSession();
+    PerfSession perfSession = SessionManager.getInstance().perfSession();
+    if (perfSession.sessionId().isEmpty()) {
+      SessionManager.getInstance().registerForSessionUpdates(sessionAwareObject);
+    } else {
+      this.startSession = SessionManager.getInstance().perfSession();
+      dispatchAppStartTrace();
+    }
+
     AndroidLogger.getInstance()
         .debug(
             "onResume(): "
@@ -374,15 +386,26 @@ public synchronized void onActivityResumed(Activity activity) {
                 + getClassLoadTimeCompat().getDurationMicros(onResumeTime)
                 + " microseconds");
 
-    // Log the app start trace in a non-main thread.
-    executorService.execute(this::logAppStartTrace);
-
     if (!isExperimentTTIDEnabled) {
       // After AppStart trace is logged, we can unregister this callback.
       unregisterActivityLifecycleCallbacks();
     }
   }
 
+  private void dispatchAppStartTrace() {
+    // Log the app start trace in a non-main thread.
+    executorService.execute(this::logAppStartTrace);
+  }
+
+  @Override
+  public void updateSession(PerfSession session) {
+    if (!session.sessionId().isEmpty()) {
+      SessionManager.getInstance().unregisterForSessionUpdates(sessionAwareObject);
+      this.startSession = session;
+      dispatchAppStartTrace();
+    }
+  }
+
   /** Helper for logging all experiments in one trace. */
   private void logExperimentTrace(TraceMetric.Builder metric) {
     if (this.preDrawPostTime == null

firebase-sessions/src/androidTest/kotlin/com/google/firebase/sessions/FirebaseSessionsTests.kt

@@ -23,6 +23,7 @@ import com.google.firebase.Firebase
 import com.google.firebase.FirebaseApp
 import com.google.firebase.FirebaseOptions
 import com.google.firebase.initialize
+import com.google.firebase.sessions.settings.SessionsSettings
 import org.junit.After
 import org.junit.Before
 import org.junit.Test
@@ -57,6 +58,13 @@ class FirebaseSessionsTests {
     assertThat(FirebaseSessions.instance).isNotNull()
   }
 
+  @Test
+  fun firebaseSessionsDependenciesDoInitialize() {
+    assertThat(SessionFirelogPublisher.instance).isNotNull()
+    assertThat(SessionGenerator.instance).isNotNull()
+    assertThat(SessionsSettings.instance).isNotNull()
+  }
+
   companion object {
     private const val APP_ID = "1:1:android:1a"
     private const val API_KEY = "API-KEY-API-KEY-API-KEY-API-KEY-API-KEY"

firebase-sessions/src/main/AndroidManifest.xml

@@ -18,6 +18,10 @@
   <!--<uses-sdk android:minSdkVersion="16"/>-->
 
   <application>
+    <service
+      android:name="com.google.firebase.sessions.SessionLifecycleService"
+      android:enabled="true"
+      android:exported="false" />
     <service android:name="com.google.firebase.components.ComponentDiscoveryService"
       android:exported="false">
       <meta-data

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/FirebaseSessions.kt

@@ -18,12 +18,9 @@ package com.google.firebase.sessions
 
 import android.app.Application
 import android.util.Log
-import com.google.android.datatransport.TransportFactory
 import com.google.firebase.Firebase
 import com.google.firebase.FirebaseApp
 import com.google.firebase.app
-import com.google.firebase.inject.Provider
-import com.google.firebase.installations.FirebaseInstallationsApi
 import com.google.firebase.sessions.api.FirebaseSessionsDependencies
 import com.google.firebase.sessions.api.SessionSubscriber
 import com.google.firebase.sessions.settings.SessionsSettings
@@ -33,47 +30,30 @@ import kotlinx.coroutines.CoroutineDispatcher
 class FirebaseSessions
 internal constructor(
   private val firebaseApp: FirebaseApp,
-  firebaseInstallations: FirebaseInstallationsApi,
-  backgroundDispatcher: CoroutineDispatcher,
-  blockingDispatcher: CoroutineDispatcher,
-  transportFactoryProvider: Provider<TransportFactory>,
+  internal val backgroundDispatcher: CoroutineDispatcher,
+  private val sessionFirelogPublisher: SessionFirelogPublisher,
+  sessionGenerator: SessionGenerator,
+  private val sessionSettings: SessionsSettings,
 ) {
-  private val applicationInfo = SessionEvents.getApplicationInfo(firebaseApp)
-  private val sessionSettings =
-    SessionsSettings(
-      firebaseApp.applicationContext,
-      blockingDispatcher,
-      backgroundDispatcher,
-      firebaseInstallations,
-      applicationInfo,
-    )
-  private val timeProvider: TimeProvider = Time()
-  private val sessionGenerator: SessionGenerator
-  private val eventGDTLogger = EventGDTLogger(transportFactoryProvider)
-  private val sessionCoordinator = SessionCoordinator(firebaseInstallations, eventGDTLogger)
+
+  // TODO: This needs to be moved into the service to be consistent across multiple processes.
+  private val collectEvents: Boolean
 
   init {
-    sessionGenerator = SessionGenerator(collectEvents = shouldCollectEvents(), timeProvider)
-
-    val sessionInitiateListener =
-      object : SessionInitiateListener {
-        // Avoid making a public function in FirebaseSessions for onInitiateSession.
-        override suspend fun onInitiateSession(sessionDetails: SessionDetails) {
-          initiateSessionStart(sessionDetails)
-        }
-      }
+    collectEvents = shouldCollectEvents()
 
     val sessionInitiator =
       SessionInitiator(
-        timeProvider,
+        timeProvider = WallClock,
         backgroundDispatcher,
-        sessionInitiateListener,
+        ::initiateSessionStart,
         sessionSettings,
         sessionGenerator,
       )
 
     val appContext = firebaseApp.applicationContext.applicationContext
     if (appContext is Application) {
+      SessionLifecycleClient.bindToService(appContext)
       appContext.registerActivityLifecycleCallbacks(sessionInitiator.activityLifecycleCallbacks)
 
       firebaseApp.addLifecycleEventListener { _, _ ->
@@ -97,14 +77,6 @@ internal constructor(
       "Registering Sessions SDK subscriber with name: ${subscriber.sessionSubscriberName}, " +
         "data collection enabled: ${subscriber.isDataCollectionEnabled}"
     )
-
-    // Immediately call the callback if Sessions generated a session before the
-    // subscriber subscribed, otherwise subscribers might miss the first session.
-    if (sessionGenerator.hasGenerateSession) {
-      subscriber.onSessionChanged(
-        SessionSubscriber.SessionDetails(sessionGenerator.currentSession.sessionId)
-      )
-    }
   }
 
   private suspend fun initiateSessionStart(sessionDetails: SessionDetails) {
@@ -138,23 +110,10 @@ internal constructor(
       return
     }
 
-    if (!sessionGenerator.collectEvents) {
+    if (!collectEvents) {
       Log.d(TAG, "Sessions SDK has dropped this session due to sampling.")
       return
     }
-
-    try {
-      val sessionEvent =
-        SessionEvents.startSession(firebaseApp, sessionDetails, sessionSettings, subscribers)
-      sessionCoordinator.attemptLoggingSessionEvent(sessionEvent)
-    } catch (ex: IllegalStateException) {
-      // This can happen if the app suddenly deletes the instance of FirebaseApp.
-      Log.w(
-        TAG,
-        "FirebaseApp is not initialized. Sessions library will not collect session data.",
-        ex
-      )
-    }
   }
 
   /** Calculate whether we should sample events using [sessionSettings] data. */
@@ -169,9 +128,18 @@ internal constructor(
 
     @JvmStatic
     val instance: FirebaseSessions
-      get() = getInstance(Firebase.app)
+      get() = Firebase.app.get(FirebaseSessions::class.java)
 
     @JvmStatic
-    fun getInstance(app: FirebaseApp): FirebaseSessions = app.get(FirebaseSessions::class.java)
+    @Deprecated(
+      "Firebase Sessions only supports the Firebase default app.",
+      ReplaceWith("FirebaseSessions.instance"),
+    )
+    fun getInstance(app: FirebaseApp): FirebaseSessions =
+      if (app == Firebase.app) {
+        app.get(FirebaseSessions::class.java)
+      } else {
+        throw IllegalArgumentException("Firebase Sessions only supports the Firebase default app.")
+      }
   }
 }

firebase-sessions/src/main/kotlin/com/google/firebase/sessions/FirebaseSessionsRegistrar.kt

@@ -26,10 +26,11 @@ import com.google.firebase.components.Qualified.qualified
 import com.google.firebase.components.Qualified.unqualified
 import com.google.firebase.installations.FirebaseInstallationsApi
 import com.google.firebase.platforminfo.LibraryVersionComponent
+import com.google.firebase.sessions.settings.SessionsSettings
 import kotlinx.coroutines.CoroutineDispatcher
 
 /**
- * [ComponentRegistrar] for setting up [FirebaseSessions].
+ * [ComponentRegistrar] for setting up [FirebaseSessions] and its internal dependencies.
  *
  * @hide
  */
@@ -40,24 +41,60 @@ internal class FirebaseSessionsRegistrar : ComponentRegistrar {
       Component.builder(FirebaseSessions::class.java)
         .name(LIBRARY_NAME)
         .add(Dependency.required(firebaseApp))
-        .add(Dependency.required(firebaseInstallationsApi))
         .add(Dependency.required(backgroundDispatcher))
-        .add(Dependency.required(blockingDispatcher))
-        .add(Dependency.requiredProvider(transportFactory))
+        .add(Dependency.required(sessionFirelogPublisher))
+        .add(Dependency.required(sessionGenerator))
+        .add(Dependency.required(sessionsSettings))
         .factory { container ->
           FirebaseSessions(
+            container.get(firebaseApp),
+            container.get(backgroundDispatcher),
+            container.get(sessionFirelogPublisher),
+            container.get(sessionGenerator),
+            container.get(sessionsSettings),
+          )
+        }
+        .build(),
+      Component.builder(SessionGenerator::class.java)
+        .name("session-generator")
+        .factory { SessionGenerator(timeProvider = WallClock) }
+        .build(),
+      Component.builder(SessionFirelogPublisher::class.java)
+        .name("session-publisher")
+        .add(Dependency.required(firebaseApp))
+        .add(Dependency.required(firebaseInstallationsApi))
+        .add(Dependency.required(sessionsSettings))
+        .add(Dependency.requiredProvider(transportFactory))
+        .add(Dependency.required(backgroundDispatcher))
+        .factory { container ->
+          SessionFirelogPublisher(
             container.get(firebaseApp),
             container.get(firebaseInstallationsApi),
+            container.get(sessionsSettings),
+            EventGDTLogger(container.getProvider(transportFactory)),
             container.get(backgroundDispatcher),
+          )
+        }
+        .build(),
+      Component.builder(SessionsSettings::class.java)
+        .name("sessions-settings")
+        .add(Dependency.required(firebaseApp))
+        .add(Dependency.required(blockingDispatcher))
+        .add(Dependency.required(backgroundDispatcher))
+        .add(Dependency.required(firebaseInstallationsApi))
+        .factory { container ->
+          SessionsSettings(
+            container.get(firebaseApp),
             container.get(blockingDispatcher),
-            container.getProvider(transportFactory),
+            container.get(backgroundDispatcher),
+            container.get(firebaseInstallationsApi),
           )
         }
         .build(),
-      LibraryVersionComponent.create(LIBRARY_NAME, BuildConfig.VERSION_NAME)
+      LibraryVersionComponent.create(LIBRARY_NAME, BuildConfig.VERSION_NAME),
     )
 
-  companion object {
+  private companion object {
     private const val LIBRARY_NAME = "fire-sessions"
 
     private val firebaseApp = unqualified(FirebaseApp::class.java)
@@ -67,5 +104,8 @@ internal class FirebaseSessionsRegistrar : ComponentRegistrar {
     private val blockingDispatcher =
       qualified(Blocking::class.java, CoroutineDispatcher::class.java)
     private val transportFactory = unqualified(TransportFactory::class.java)
+    private val sessionFirelogPublisher = unqualified(SessionFirelogPublisher::class.java)
+    private val sessionGenerator = unqualified(SessionGenerator::class.java)
+    private val sessionsSettings = unqualified(SessionsSettings::class.java)
   }
 }