Use AQS for Firebase Performance sessions.

firebase-perf/firebase-perf.gradle

@@ -118,7 +118,7 @@ dependencies {
     api("com.google.firebase:firebase-components:18.0.0")
     api("com.google.firebase:firebase-config:21.5.0")
     api("com.google.firebase:firebase-installations:17.2.0")
-    api("com.google.firebase:firebase-sessions:2.0.7") {
+    api(project(":firebase-sessions")) {
         exclude group: 'com.google.firebase', module: 'firebase-common'
         exclude group: 'com.google.firebase', module: 'firebase-common-ktx'
         exclude group: 'com.google.firebase', module: 'firebase-components'

firebase-perf/src/main/java/com/google/firebase/perf/FirebasePerfEarly.java

@@ -20,6 +20,7 @@
 import com.google.firebase.StartupTime;
 import com.google.firebase.perf.application.AppStateMonitor;
 import com.google.firebase.perf.config.ConfigResolver;
+import com.google.firebase.perf.logging.AndroidLogger;
 import com.google.firebase.perf.metrics.AppStartTrace;
 import com.google.firebase.perf.session.SessionManager;
 import java.util.concurrent.Executor;
@@ -51,12 +52,11 @@ public FirebasePerfEarly(
       uiExecutor.execute(new AppStartTrace.StartFromBackgroundRunnable(appStartTrace));
     }
 
-    // TODO: Bring back Firebase Sessions dependency to watch for updates to sessions.
-
     // In the case of cold start, we create a session and start collecting gauges as early as
     // possible.
     // There is code in SessionManager that prevents us from resetting the session twice in case
     // of app cold start.
+    AndroidLogger.getInstance().debug("Initializing Gauge Collection");
     SessionManager.getInstance().initializeGaugeCollection();
   }
 }

firebase-perf/src/main/java/com/google/firebase/perf/FirebasePerfRegistrar.java

@@ -30,6 +30,8 @@
 import com.google.firebase.perf.injection.modules.FirebasePerformanceModule;
 import com.google.firebase.platforminfo.LibraryVersionComponent;
 import com.google.firebase.remoteconfig.RemoteConfigComponent;
+import com.google.firebase.sessions.api.FirebaseSessionsDependencies;
+import com.google.firebase.sessions.api.SessionSubscriber;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.Executor;
@@ -47,6 +49,10 @@ public class FirebasePerfRegistrar implements ComponentRegistrar {
   private static final String LIBRARY_NAME = "fire-perf";
   private static final String EARLY_LIBRARY_NAME = "fire-perf-early";
 
+  static {
+    FirebaseSessionsDependencies.addDependency(SessionSubscriber.Name.PERFORMANCE);
+  }
+
   @Override
   @Keep
   public List<Component<?>> getComponents() {

firebase-perf/src/main/java/com/google/firebase/perf/FirebasePerformance.java

@@ -36,12 +36,14 @@
 import com.google.firebase.perf.logging.ConsoleUrlGenerator;
 import com.google.firebase.perf.metrics.HttpMetric;
 import com.google.firebase.perf.metrics.Trace;
+import com.google.firebase.perf.session.FirebasePerformanceSessionSubscriber;
 import com.google.firebase.perf.session.SessionManager;
 import com.google.firebase.perf.transport.TransportManager;
 import com.google.firebase.perf.util.Constants;
 import com.google.firebase.perf.util.ImmutableBundle;
 import com.google.firebase.perf.util.Timer;
 import com.google.firebase.remoteconfig.RemoteConfigComponent;
+import com.google.firebase.sessions.api.FirebaseSessionsDependencies;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.net.URL;
@@ -136,11 +138,6 @@ public static FirebasePerformance getInstance() {
   // to false if it's been force disabled or it is set to null if neither.
   @Nullable private Boolean mPerformanceCollectionForceEnabledState = null;
 
-  private final FirebaseApp firebaseApp;
-  private final Provider<RemoteConfigComponent> firebaseRemoteConfigProvider;
-  private final FirebaseInstallationsApi firebaseInstallationsApi;
-  private final Provider<TransportFactory> transportFactoryProvider;
-
   /**
    * Constructs the FirebasePerformance class and allows injecting dependencies.
    *
@@ -166,23 +163,21 @@ public static FirebasePerformance getInstance() {
       ConfigResolver configResolver,
       SessionManager sessionManager) {
 
-    this.firebaseApp = firebaseApp;
-    this.firebaseRemoteConfigProvider = firebaseRemoteConfigProvider;
-    this.firebaseInstallationsApi = firebaseInstallationsApi;
-    this.transportFactoryProvider = transportFactoryProvider;
-
     if (firebaseApp == null) {
       this.mPerformanceCollectionForceEnabledState = false;
       this.configResolver = configResolver;
       this.mMetadataBundle = new ImmutableBundle(new Bundle());
       return;
     }
 
+    // Prioritize registering the FirebaseSession dependency to have the session
+    // `setApplicationContext`.
+    FirebaseSessionsDependencies.register(
+        FirebasePerformanceSessionSubscriber.Companion.getInstance());
     TransportManager.getInstance()
         .initialize(firebaseApp, firebaseInstallationsApi, transportFactoryProvider);
 
     Context appContext = firebaseApp.getApplicationContext();
-    // TODO(b/110178816): Explore moving off of main thread.
     mMetadataBundle = extractMetadata(appContext);
 
     remoteConfigManager.setFirebaseRemoteConfigProvider(firebaseRemoteConfigProvider);
@@ -192,13 +187,19 @@ public static FirebasePerformance getInstance() {
     sessionManager.setApplicationContext(appContext);
 
     mPerformanceCollectionForceEnabledState = configResolver.getIsPerformanceCollectionEnabled();
+    FirebaseSessionsDependencies.register(
+        new FirebasePerformanceSessionSubscriber(isPerformanceCollectionEnabled()));
+
     if (logger.isLogcatEnabled() && isPerformanceCollectionEnabled()) {
       logger.info(
           String.format(
               "Firebase Performance Monitoring is successfully initialized! In a minute, visit the Firebase console to view your data: %s",
               ConsoleUrlGenerator.generateDashboardUrl(
                   firebaseApp.getOptions().getProjectId(), appContext.getPackageName())));
     }
+
+    SessionManagerKt sessionSubscriber = new SessionManagerKt(isPerformanceCollectionEnabled());
+    FirebaseSessionsDependencies.register(sessionSubscriber);
   }
 
   /**
@@ -282,7 +283,7 @@ public synchronized void setPerformanceCollectionEnabled(@Nullable Boolean enabl
       return;
     }
 
-    if (configResolver.getIsPerformanceCollectionDeactivated()) {
+    if (Boolean.TRUE.equals(configResolver.getIsPerformanceCollectionDeactivated())) {
       logger.info("Firebase Performance is permanently disabled");
       return;
     }

firebase-perf/src/main/java/com/google/firebase/perf/config/ConfigResolver.java

@@ -116,7 +116,7 @@ public void setMetadataBundle(ImmutableBundle bundle) {
   /** Default API to call for whether performance monitoring is currently silent. */
   public boolean isPerformanceMonitoringEnabled() {
     Boolean isPerformanceCollectionEnabled = getIsPerformanceCollectionEnabled();
-    return (isPerformanceCollectionEnabled == null || isPerformanceCollectionEnabled == true)
+    return (isPerformanceCollectionEnabled == null || isPerformanceCollectionEnabled)
         && getIsServiceCollectionEnabled();
   }
 
@@ -131,7 +131,7 @@ public Boolean getIsPerformanceCollectionEnabled() {
     // return developer config.
     // 4. Else, return null. Because Firebase Performance will read highlevel Firebase flag in this
     // case.
-    if (getIsPerformanceCollectionDeactivated()) {
+    if (Boolean.TRUE.equals(getIsPerformanceCollectionDeactivated())) {
       // 1. If developer has deactivated Firebase Performance in Manifest, return false.
       return false;
     }
@@ -186,7 +186,7 @@ public void setIsPerformanceCollectionEnabled(Boolean isEnabled) {
     // 2. Otherwise, save this configuration in device cache.
 
     // If collection is deactivated, skip the action to save user configuration.
-    if (getIsPerformanceCollectionDeactivated()) {
+    if (Boolean.TRUE.equals(getIsPerformanceCollectionDeactivated())) {
       return;
     }
 

firebase-perf/src/main/java/com/google/firebase/perf/session/FirebasePerformanceSessionSubscriber.kt

@@ -0,0 +1,58 @@
+package com.google.firebase.perf.session
+
+import com.google.firebase.perf.config.ConfigResolver
+import com.google.firebase.perf.logging.AndroidLogger
+import com.google.firebase.perf.session.gauges.GaugeManager
+import com.google.firebase.sessions.api.SessionSubscriber
+
+class FirebasePerformanceSessionSubscriber(private val dataCollectionEnabled: Boolean) :
+  SessionSubscriber {
+  private val perfSessionToAqs: MutableMap<String, SessionSubscriber.SessionDetails?> =
+    mutableMapOf()
+
+  override val isDataCollectionEnabled: Boolean
+    get() = dataCollectionEnabled
+
+  override val sessionSubscriberName: SessionSubscriber.Name
+    get() = SessionSubscriber.Name.PERFORMANCE
+
+  override fun onSessionChanged(sessionDetails: SessionSubscriber.SessionDetails) {
+    AndroidLogger.getInstance().debug("AQS Session Changed: $sessionDetails")
+    val currentInternalSessionId = SessionManager.getInstance().perfSession().internalSessionId
+
+    // There can be situations where a new [PerfSession] was created, but an AQS wasn't
+    // available (during cold start).
+    if (perfSessionToAqs[currentInternalSessionId] == null) {
+      perfSessionToAqs[currentInternalSessionId] = sessionDetails
+    } else {
+      val newSession = PerfSession.createNewSession()
+      SessionManager.getInstance().updatePerfSession(newSession)
+      perfSessionToAqs[newSession.internalSessionId] = sessionDetails
+    }
+
+    // Always log GaugeMetadata when a session changes.
+    GaugeManager.getInstance().logGaugeMetadata(sessionDetails.sessionId)
+  }
+
+  fun reportPerfSession(perfSessionId: String) {
+    perfSessionToAqs[perfSessionId] = null
+  }
+
+  fun getAqsMappedToPerfSession(perfSessionId: String): String {
+    AndroidLogger.getInstance()
+      .debug("AQS for perf session $perfSessionId is ${perfSessionToAqs[perfSessionId]?.sessionId}")
+    return perfSessionToAqs[perfSessionId]?.sessionId ?: perfSessionId
+  }
+
+  fun clearSessionForTest() {
+    perfSessionToAqs.clear()
+  }
+
+  companion object {
+    val instance: FirebasePerformanceSessionSubscriber by lazy {
+      FirebasePerformanceSessionSubscriber(
+        ConfigResolver.getInstance().isPerformanceMonitoringEnabled
+      )
+    }
+  }
+}

firebase-perf/src/main/java/com/google/firebase/perf/session/PerfSession.java

@@ -23,25 +23,28 @@
 import com.google.firebase.perf.util.Clock;
 import com.google.firebase.perf.util.Timer;
 import com.google.firebase.perf.v1.SessionVerbosity;
+import com.google.firebase.sessions.api.SessionSubscriber;
 import java.util.List;
+import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 
 /** Details of a session including a unique Id and related information. */
 public class PerfSession implements Parcelable {
 
+  private static final String SESSION_ID_PREFIX = "fireperf-session";
   private final String sessionId;
   private final Timer creationTime;
+  @Nullable private String aqsSessionId;
 
   private boolean isGaugeAndEventCollectionEnabled = false;
 
   /*
    * Creates a PerfSession object and decides what metrics to collect.
    */
-  public static PerfSession createWithId(@NonNull String sessionId) {
-    String prunedSessionId = sessionId.replace("-", "");
+  public static PerfSession createNewSession() {
+    String prunedSessionId = SESSION_ID_PREFIX + UUID.randomUUID().toString().replace("-", "");
     PerfSession session = new PerfSession(prunedSessionId, new Clock());
     session.setGaugeAndEventCollectionEnabled(shouldCollectGaugesAndEvents());
-
     return session;
   }
 
@@ -50,6 +53,11 @@ public static PerfSession createWithId(@NonNull String sessionId) {
   public PerfSession(String sessionId, Clock clock) {
     this.sessionId = sessionId;
     creationTime = clock.getTime();
+    // Every time a PerfSession is created, it sets the AQS to null. Once an AQS is received,
+    // SessionManagerKt verifies if this is an active session, and sets the AQS session ID.
+    // The assumption is that new PerfSessions *should* be limited to either App Start, or through
+    // AQS.
+    FirebasePerformanceSessionSubscriber.Companion.getInstance().reportPerfSession(sessionId);
   }
 
   private PerfSession(@NonNull Parcel in) {
@@ -59,9 +67,27 @@ private PerfSession(@NonNull Parcel in) {
     creationTime = in.readParcelable(Timer.class.getClassLoader());
   }
 
-  /** Returns the sessionId of the object. */
+  /** Returns the sessionId of the session. */
   public String sessionId() {
-    return sessionId;
+    return this.sessionId;
+  }
+
+  private String aqsSessionId() {
+    return FirebasePerformanceSessionSubscriber.Companion.getInstance()
+        .getAqsMappedToPerfSession(this.sessionId);
+  }
+
+  /** Returns the AQS sessionId for the given session. */
+  @Nullable
+  public String aqsSessionId() {
+    return aqsSessionId;
+  }
+
+  /** Sets the AQS sessionId for the given session. */
+  public void setAQSId(SessionSubscriber.SessionDetails aqs) {
+    if (aqsSessionId == null) {
+      aqsSessionId = aqs.getSessionId();
+    }
   }
 
   /**
@@ -113,8 +139,9 @@ public boolean isSessionRunningTooLong() {
 
   /** Creates and returns the proto object for PerfSession object. */
   public com.google.firebase.perf.v1.PerfSession build() {
+    // TODO(b/394127311): Switch to using AQS.
     com.google.firebase.perf.v1.PerfSession.Builder sessionMetric =
-        com.google.firebase.perf.v1.PerfSession.newBuilder().setSessionId(sessionId);
+        com.google.firebase.perf.v1.PerfSession.newBuilder().setSessionId(aqsSessionId());
 
     // If gauge collection is enabled, enable gauge collection verbosity.
     if (isGaugeAndEventCollectionEnabled) {