[DRAFT] Fireperf AQS changes

firebase-perf/firebase-perf.gradle

@@ -72,13 +72,15 @@ android {
         buildConfigField("String", "TRANSPORT_LOG_SRC", "String.valueOf(\"FIREPERF\")")
         buildConfigField("Boolean", "ENFORCE_DEFAULT_LOG_SRC", "Boolean.valueOf(false)")
         buildConfigField("String", "FIREPERF_VERSION_NAME", "String.valueOf(\"" + property("version") + "\")")
+        buildConfigField("Boolean", "ENFORCE_LEGACY_SESSIONS", "Boolean.valueOf(false)")
 
         if (project.hasProperty("fireperfBuildForAutopush")) {
             // This allows the SDK to be built for "Autopush" env when the mentioned flag
             // (-PfireperfBuildForAutopush) is passed in the gradle build command (of either the
             // SDK or the Test App).
             buildConfigField("String", "TRANSPORT_LOG_SRC", "String.valueOf(\"FIREPERF_AUTOPUSH\")")
             buildConfigField("Boolean", "ENFORCE_DEFAULT_LOG_SRC", "Boolean.valueOf(true)")
+            buildConfigField("Boolean", "ENFORCE_LEGACY_SESSIONS", "Boolean.valueOf(true)")
         }
 
         minSdkVersion project.minSdkVersion
@@ -124,7 +126,7 @@ dependencies {
     api("com.google.firebase:firebase-installations:18.0.0") {
         exclude group: 'com.google.firebase', module: 'firebase-common-ktx'
     }
-    api("com.google.firebase:firebase-sessions:2.0.7") {
+    api("com.google.firebase:firebase-sessions:3.0.0") {
         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

@@ -21,7 +21,8 @@
 import com.google.firebase.perf.application.AppStateMonitor;
 import com.google.firebase.perf.config.ConfigResolver;
 import com.google.firebase.perf.metrics.AppStartTrace;
-import com.google.firebase.perf.session.SessionManager;
+import com.google.firebase.perf.session.FirebasePerformanceSessionSubscriber;
+import com.google.firebase.sessions.api.FirebaseSessionsDependencies;
 import java.util.concurrent.Executor;
 
 /**
@@ -41,6 +42,10 @@ public FirebasePerfEarly(
     ConfigResolver configResolver = ConfigResolver.getInstance();
     configResolver.setApplicationContext(context);
 
+    // Register FirebasePerformance as a subscriber ASAP - which will start collecting gauges if the
+    // FirebaseSession is verbose.
+    FirebaseSessionsDependencies.register(new FirebasePerformanceSessionSubscriber(configResolver));
+
     AppStateMonitor appStateMonitor = AppStateMonitor.getInstance();
     appStateMonitor.registerActivityLifecycleCallbacks(context);
     appStateMonitor.registerForAppColdStart(new FirebasePerformanceInitializer());
@@ -50,13 +55,5 @@ public FirebasePerfEarly(
       appStartTrace.registerActivityLifecycleCallbacks(context);
       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.
-    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 +49,11 @@ public class FirebasePerfRegistrar implements ComponentRegistrar {
   private static final String LIBRARY_NAME = "fire-perf";
   private static final String EARLY_LIBRARY_NAME = "fire-perf-early";
 
+  static {
+    // Add Firebase Performance as a dependency of Sessions when this class is loaded into memory.
+    FirebaseSessionsDependencies.addDependency(SessionSubscriber.Name.PERFORMANCE);
+  }
+
   @Override
   @Keep
   public List<Component<?>> getComponents() {

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

@@ -34,6 +34,7 @@
 import com.google.firebase.perf.config.RemoteConfigManager;
 import com.google.firebase.perf.logging.AndroidLogger;
 import com.google.firebase.perf.logging.ConsoleUrlGenerator;
+import com.google.firebase.perf.logging.FirebaseSessionsEnforcementCheck;
 import com.google.firebase.perf.metrics.HttpMetric;
 import com.google.firebase.perf.metrics.Trace;
 import com.google.firebase.perf.session.SessionManager;
@@ -136,11 +137,6 @@ 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 +162,18 @@ 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;
     }
+    FirebaseSessionsEnforcementCheck.setEnforcement(BuildConfig.ENFORCE_LEGACY_SESSIONS);
 
     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);
@@ -192,6 +183,7 @@ public static FirebasePerformance getInstance() {
     sessionManager.setApplicationContext(appContext);
 
     mPerformanceCollectionForceEnabledState = configResolver.getIsPerformanceCollectionEnabled();
+
     if (logger.isLogcatEnabled() && isPerformanceCollectionEnabled()) {
       logger.info(
           String.format(
@@ -282,7 +274,7 @@ 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/logging/FirebaseSessionsEnforcementCheck.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.perf.logging
+
+import com.google.firebase.perf.session.isLegacy
+import com.google.firebase.perf.v1.PerfSession as ProtoPerfSession
+
+class FirebaseSessionsEnforcementCheck {
+  companion object {
+    /** When enabled, failed preconditions will cause assertion errors for debugging. */
+    @JvmStatic var enforcement: Boolean = false
+    private var logger: AndroidLogger = AndroidLogger.getInstance()
+
+    @JvmStatic
+    fun checkSessionsList(sessions: List<ProtoPerfSession>, failureMessage: String) {
+      if (sessions.count { it.sessionId.isLegacy() } == sessions.size) {
+        sessions.forEach { checkSession(it.sessionId, failureMessage) }
+      }
+    }
+
+    @JvmStatic
+    fun checkSession(sessionId: String, failureMessage: String) {
+      if (sessionId.isLegacy()) {
+        logger.verbose("Contains Legacy Session ${sessionId}: $failureMessage")
+        assert(!enforcement) { failureMessage }
+      }
+    }
+  }
+}

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

@@ -14,6 +14,8 @@
 
 package com.google.firebase.perf.metrics;
 
+import static com.google.firebase.perf.util.AppProcessesProvider.getAppProcesses;
+
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.app.ActivityManager;
@@ -552,11 +554,8 @@ public static boolean isAnyAppProcessInForeground(Context appContext) {
     if (activityManager == null) {
       return true;
     }
-    List<ActivityManager.RunningAppProcessInfo> appProcesses =
-        activityManager.getRunningAppProcesses();
-    if (appProcesses != null) {
-      String appProcessName = appContext.getPackageName();
-      String allowedAppProcessNamePrefix = appProcessName + ":";
+    List<ActivityManager.RunningAppProcessInfo> appProcesses = getAppProcesses(appContext);
+    if (!appProcesses.isEmpty()) {
       for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) {
         if (appProcess.importance != ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
           continue;

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

@@ -224,7 +224,7 @@ public NetworkRequestMetricBuilder setCustomAttributes(Map<String, String> attri
    * point depending upon the current {@link PerfSession} verbosity.
    *
    * @see GaugeManager#collectGaugeMetricOnce(Timer)
-   * @see PerfSession#isGaugeAndEventCollectionEnabled()
+   * @see PerfSession#isVerbose()
    */
   public NetworkRequestMetricBuilder setRequestStartTimeMicros(long time) {
     SessionManager sessionManager = SessionManager.getInstance();
@@ -234,7 +234,7 @@ public NetworkRequestMetricBuilder setRequestStartTimeMicros(long time) {
     builder.setClientStartTimeUs(time);
     updateSession(perfSession);
 
-    if (perfSession.isGaugeAndEventCollectionEnabled()) {
+    if (perfSession.isVerbose()) {
       gaugeManager.collectGaugeMetricOnce(perfSession.getTimer());
     }
 
@@ -265,12 +265,12 @@ public long getTimeToResponseInitiatedMicros() {
    * point depending upon the current {@link PerfSession} Verbosity.
    *
    * @see GaugeManager#collectGaugeMetricOnce(Timer)
-   * @see PerfSession#isGaugeAndEventCollectionEnabled()
+   * @see PerfSession#isVerbose()
    */
   public NetworkRequestMetricBuilder setTimeToResponseCompletedMicros(long time) {
     builder.setTimeToResponseCompletedUs(time);
 
-    if (SessionManager.getInstance().perfSession().isGaugeAndEventCollectionEnabled()) {
+    if (SessionManager.getInstance().perfSession().isVerbose()) {
       gaugeManager.collectGaugeMetricOnce(SessionManager.getInstance().perfSession().getTimer());
     }
 

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

@@ -233,7 +233,7 @@ public void start() {
 
     updateSession(perfSession);
 
-    if (perfSession.isGaugeAndEventCollectionEnabled()) {
+    if (perfSession.isVerbose()) {
       gaugeManager.collectGaugeMetricOnce(perfSession.getTimer());
     }
   }
@@ -259,7 +259,7 @@ public void stop() {
       if (!name.isEmpty()) {
         transportManager.log(new TraceMetricBuilder(this).build(), getAppState());
 
-        if (SessionManager.getInstance().perfSession().isGaugeAndEventCollectionEnabled()) {
+        if (SessionManager.getInstance().perfSession().isVerbose()) {
           gaugeManager.collectGaugeMetricOnce(
               SessionManager.getInstance().perfSession().getTimer());
         }

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

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.perf.session
+
+import com.google.firebase.perf.config.ConfigResolver
+import com.google.firebase.perf.logging.FirebaseSessionsEnforcementCheck.Companion.checkSession
+import com.google.firebase.sessions.api.SessionSubscriber
+
+class FirebasePerformanceSessionSubscriber(val configResolver: ConfigResolver) : SessionSubscriber {
+
+  override val sessionSubscriberName: SessionSubscriber.Name = SessionSubscriber.Name.PERFORMANCE
+
+  override val isDataCollectionEnabled: Boolean
+    get() = configResolver.isPerformanceCollectionEnabled ?: false
+
+  override fun onSessionChanged(sessionDetails: SessionSubscriber.SessionDetails) {
+    val currentPerfSession = SessionManager.getInstance().perfSession()
+    // TODO(b/394127311): Add logic to deal with app start gauges if necessary.
+    checkSession(currentPerfSession.sessionId(), "Existing session in onSessionChanged().")
+
+    val updatedSession = PerfSession.createWithId(sessionDetails.sessionId)
+    SessionManager.getInstance().updatePerfSession(updatedSession)
+  }
+}

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

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.perf.session
+
+import com.google.firebase.perf.util.Constants
+import java.util.UUID
+
+/** Identifies whether the [PerfSession] is legacy or not. */
+fun PerfSession.isLegacy(): Boolean {
+  return this.sessionId().isLegacy()
+}
+
+/** Identifies whether the string is from a legacy [PerfSession]. */
+fun String.isLegacy(): Boolean {
+  return this.startsWith(Constants.UNDEFINED_AQS_ID_PREFIX)
+}
+
+/** Creates a valid session ID for [PerfSession] that can be predictably identified as legacy. */
+fun createLegacySessionId(): String {
+  val uuid = UUID.randomUUID().toString().replace("-", "")
+  return uuid.replaceRange(
+    0,
+    Constants.UNDEFINED_AQS_ID_PREFIX.length,
+    Constants.UNDEFINED_AQS_ID_PREFIX
+  )
+}