Feat: Measure app start time

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+* Feat: Measure app start time (#1487)
+
 ## 5.0.1
 
 * Fix: Sources and Javadoc artifacts were mixed up (#1515)

sentry-android-core/api/sentry-android-core.api

@@ -123,6 +123,17 @@ public final class io/sentry/android/core/SentryInitProvider : android/content/C
 	public fun update (Landroid/net/Uri;Landroid/content/ContentValues;Ljava/lang/String;[Ljava/lang/String;)I
 }
 
+public final class io/sentry/android/core/SentryPerformanceProvider : android/content/ContentProvider {
+	public fun <init> ()V
+	public fun attachInfo (Landroid/content/Context;Landroid/content/pm/ProviderInfo;)V
+	public fun delete (Landroid/net/Uri;Ljava/lang/String;[Ljava/lang/String;)I
+	public fun getType (Landroid/net/Uri;)Ljava/lang/String;
+	public fun insert (Landroid/net/Uri;Landroid/content/ContentValues;)Landroid/net/Uri;
+	public fun onCreate ()Z
+	public fun query (Landroid/net/Uri;[Ljava/lang/String;Ljava/lang/String;[Ljava/lang/String;Ljava/lang/String;)Landroid/database/Cursor;
+	public fun update (Landroid/net/Uri;Landroid/content/ContentValues;Ljava/lang/String;[Ljava/lang/String;)I
+}
+
 public final class io/sentry/android/core/SystemEventsBreadcrumbsIntegration : io/sentry/Integration, java/io/Closeable {
 	public fun <init> (Landroid/content/Context;)V
 	public fun <init> (Landroid/content/Context;Ljava/util/List;)V

sentry-android-core/src/main/AndroidManifest.xml

@@ -8,5 +8,11 @@
       android:name=".SentryInitProvider"
       android:authorities="${applicationId}.SentryInitProvider"
       android:exported="false"/>
+
+    <provider
+        android:name=".SentryPerformanceProvider"
+        android:authorities="${applicationId}.SentryPerformanceProvider"
+        android:initOrder="200"
+        android:exported="false"/>
   </application>
 </manifest>

sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java

@@ -8,6 +8,7 @@
 import androidx.annotation.Nullable;
 import io.sentry.Breadcrumb;
 import io.sentry.IHub;
+import io.sentry.ISpan;
 import io.sentry.ITransaction;
 import io.sentry.Integration;
 import io.sentry.Scope;
@@ -17,6 +18,7 @@
 import io.sentry.util.Objects;
 import java.io.Closeable;
 import java.io.IOException;
+import java.util.Date;
 import java.util.Map;
 import java.util.WeakHashMap;
 import org.jetbrains.annotations.NotNull;
@@ -26,6 +28,9 @@
 public final class ActivityLifecycleIntegration
     implements Integration, Closeable, Application.ActivityLifecycleCallbacks {
 
+  private static final String UI_LOAD_OP = "ui.load";
+  static final String APP_START_OP = "app.start";
+
   private final @NotNull Application application;
   private @Nullable IHub hub;
   private @Nullable SentryAndroidOptions options;
@@ -34,6 +39,11 @@ public final class ActivityLifecycleIntegration
 
   private boolean isAllActivityCallbacksAvailable;
 
+  private boolean firstActivityCreated = false;
+  private boolean firstActivityResumed = false;
+
+  private @Nullable ISpan appStartSpan;
+
   // WeakHashMap isn't thread safe but ActivityLifecycleCallbacks is only called from the
   // main-thread
   private final @NotNull WeakHashMap<Activity, ITransaction> activitiesWithOngoingTransactions =
@@ -116,8 +126,22 @@ private void startTracing(final @NonNull Activity activity) {
       stopPreviousTransactions();
 
       // we can only bind to the scope if there's no running transaction
-      final ITransaction transaction =
-          hub.startTransaction(getActivityName(activity), "navigation");
+      ITransaction transaction;
+      final String activityName = getActivityName(activity);
+
+      final Date appStartTime = AppStartState.getInstance().getAppStartTime();
+
+      // in case appStartTime isn't available, we don't create a span for it.
+      if (firstActivityCreated || appStartTime == null) {
+        transaction = hub.startTransaction(activityName, UI_LOAD_OP);
+      } else {
+        // start transaction with app start timestamp
+        transaction = hub.startTransaction(activityName, UI_LOAD_OP, appStartTime);
+        // start specific span for app start
+        // TODO: add description cold/warm or different operation? how do we break down
+        // per app start cold/warm?
+        appStartSpan = transaction.startChild(APP_START_OP, appStartTime);
+      }
 
       // lets bind to the scope so other integrations can pick it up
       hub.configureScope(
@@ -186,12 +210,19 @@ public synchronized void onActivityPreCreated(
   @Override
   public synchronized void onActivityCreated(
       final @NonNull Activity activity, final @Nullable Bundle savedInstanceState) {
+    if (!firstActivityCreated && performanceEnabled) {
+      // if Activity has savedInstanceState then its a warm start
+      // https://developer.android.com/topic/performance/vitals/launch-time#warm
+      AppStartState.getInstance().setColdStart(savedInstanceState == null);
+    }
+
     addBreadcrumb(activity, "created");
 
     // fallback call for API < 29 compatibility, otherwise it happens on onActivityPreCreated
     if (!isAllActivityCallbacksAvailable) {
       startTracing(activity);
     }
+    firstActivityCreated = true;
   }
 
   @Override
@@ -201,6 +232,17 @@ public synchronized void onActivityStarted(final @NonNull Activity activity) {
 
   @Override
   public synchronized void onActivityResumed(final @NonNull Activity activity) {
+    if (!firstActivityResumed && performanceEnabled) {
+      // sets App start as finished when the very first activity calls onResume
+      AppStartState.getInstance().setAppStartEnd();
+
+      // finishes app start span
+      if (appStartSpan != null) {
+        appStartSpan.finish();
+      }
+      firstActivityResumed = true;
+    }
+
     addBreadcrumb(activity, "resumed");
 
     // fallback call for API < 29 compatibility, otherwise it happens on onActivityPostResumed

sentry-android-core/src/main/java/io/sentry/android/core/AndroidOptionsInitializer.java

@@ -105,6 +105,7 @@ static void init(
     readDefaultOptionValues(options, context);
 
     options.addEventProcessor(new DefaultAndroidEventProcessor(context, logger, buildInfoProvider));
+    options.addEventProcessor(new PerformanceAndroidEventProcessor(options));
 
     options.setTransportGate(new AndroidTransportGate(context, options.getLogger()));
   }

sentry-android-core/src/main/java/io/sentry/android/core/AppStartState.java

@@ -0,0 +1,73 @@
+package io.sentry.android.core;
+
+import android.os.SystemClock;
+import java.util.Date;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.annotations.TestOnly;
+
+/** AppStartState holds the state of the App Start metric and appStartTime */
+final class AppStartState {
+
+  private static @NotNull AppStartState instance = new AppStartState();
+
+  private @Nullable Long appStartMillis;
+
+  private @Nullable Long appStartEndMillis;
+
+  /** The type of App start coldStart=true -> Cold start, coldStart=false -> Warm start */
+  private boolean coldStart;
+
+  /** appStart as a Date used in the App's Context */
+  private @Nullable Date appStartTime;
+
+  private AppStartState() {}
+
+  static @NotNull AppStartState getInstance() {
+    return instance;
+  }
+
+  @TestOnly
+  void resetInstance() {
+    instance = new AppStartState();
+  }
+
+  synchronized void setAppStartEnd() {
+    setAppStartEnd(SystemClock.uptimeMillis());
+  }
+
+  @TestOnly
+  void setAppStartEnd(final long appStartEndMillis) {
+    this.appStartEndMillis = appStartEndMillis;
+  }
+
+  @Nullable
+  Long getAppStartInterval() {
+    if (appStartMillis == null || appStartEndMillis == null) {
+      return null;
+    }
+    return appStartEndMillis - appStartMillis;
+  }
+
+  boolean isColdStart() {
+    return coldStart;
+  }
+
+  synchronized void setColdStart(final boolean coldStart) {
+    this.coldStart = coldStart;
+  }
+
+  @Nullable
+  Date getAppStartTime() {
+    return appStartTime;
+  }
+
+  synchronized void setAppStartTime(final long appStartMillis, final @NotNull Date appStartTime) {
+    // method is synchronized because the SDK may by init. on a background thread.
+    if (this.appStartTime != null && this.appStartMillis != null) {
+      return;
+    }
+    this.appStartTime = appStartTime;
+    this.appStartMillis = appStartMillis;
+  }
+}

sentry-android-core/src/main/java/io/sentry/android/core/DefaultAndroidEventProcessor.java

@@ -70,9 +70,6 @@ final class DefaultAndroidEventProcessor implements EventProcessor {
   @TestOnly static final String EMULATOR = "emulator";
   @TestOnly static final String SIDE_LOADED = "sideLoaded";
 
-  // it could also be a parameter and get from Sentry.init(...)
-  private static final @Nullable Date appStartTime = DateUtils.getCurrentDateTime();
-
   @TestOnly final Context context;
 
   @TestOnly final Future<Map<String, Object>> contextData;
@@ -299,7 +296,7 @@ private void mergeDebugImages(final @NotNull SentryEvent event) {
 
   private void setAppExtras(final @NotNull App app) {
     app.setAppName(getApplicationName());
-    app.setAppStartTime(appStartTime);
+    app.setAppStartTime(AppStartState.getInstance().getAppStartTime());
   }
 
   @SuppressWarnings("deprecation")

sentry-android-core/src/main/java/io/sentry/android/core/PerformanceAndroidEventProcessor.java

@@ -0,0 +1,54 @@
+package io.sentry.android.core;
+
+import static io.sentry.android.core.ActivityLifecycleIntegration.APP_START_OP;
+
+import io.sentry.EventProcessor;
+import io.sentry.protocol.MeasurementValue;
+import io.sentry.protocol.SentrySpan;
+import io.sentry.protocol.SentryTransaction;
+import java.util.List;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/** Event Processor responsible for adding Android metrics to transactions */
+final class PerformanceAndroidEventProcessor implements EventProcessor {
+
+  private final boolean tracingEnabled;
+
+  private boolean sentStartMeasurement = false;
+
+  PerformanceAndroidEventProcessor(final @NotNull SentryAndroidOptions options) {
+    tracingEnabled = options.isTracingEnabled();
+  }
+
+  @Override
+  public synchronized @NotNull SentryTransaction process(
+      @NotNull SentryTransaction transaction, @Nullable Object hint) {
+    // the app start metric is sent only once when the 1st transaction happens
+    // after the app start is collected.
+    if (!sentStartMeasurement && tracingEnabled && hasAppStartSpan(transaction.getSpans())) {
+      final Long appStartUpInterval = AppStartState.getInstance().getAppStartInterval();
+      // if appStartUpInterval is null, metrics are not ready to be sent
+      if (appStartUpInterval != null) {
+        final MeasurementValue value = new MeasurementValue((float) appStartUpInterval);
+
+        final String appStartKey =
+            AppStartState.getInstance().isColdStart() ? "app_start_cold" : "app_start_warm";
+
+        transaction.getMeasurements().put(appStartKey, value);
+        sentStartMeasurement = true;
+      }
+    }
+
+    return transaction;
+  }
+
+  private boolean hasAppStartSpan(final @NotNull List<SentrySpan> spans) {
+    for (final SentrySpan span : spans) {
+      if (span.getOp().contentEquals(APP_START_OP)) {
+        return true;
+      }
+    }
+    return false;
+  }
+}

sentry-android-core/src/main/java/io/sentry/android/core/SentryAndroid.java

@@ -1,16 +1,24 @@
 package io.sentry.android.core;
 
 import android.content.Context;
+import android.os.SystemClock;
+import io.sentry.DateUtils;
 import io.sentry.ILogger;
 import io.sentry.OptionsContainer;
 import io.sentry.Sentry;
 import io.sentry.SentryLevel;
 import java.lang.reflect.InvocationTargetException;
+import java.util.Date;
 import org.jetbrains.annotations.NotNull;
 
 /** Sentry initialization class */
 public final class SentryAndroid {
 
+  // static to rely on Class load init.
+  private static final @NotNull Date appStartTime = DateUtils.getCurrentDateTime();
+  // SystemClock.uptimeMillis() isn't affected by phone provider or clock changes.
+  private static final long appStart = SystemClock.uptimeMillis();
+
   private SentryAndroid() {}
 
   /**
@@ -51,10 +59,14 @@ public static void init(
    * @param logger your custom logger that implements ILogger
    * @param configuration Sentry.OptionsConfiguration configuration handler
    */
-  public static void init(
+  public static synchronized void init(
       @NotNull final Context context,
       @NotNull ILogger logger,
       @NotNull Sentry.OptionsConfiguration<SentryAndroidOptions> configuration) {
+    // if SentryPerformanceProvider was disabled or removed, we set the App Start when
+    // the SDK is called.
+    AppStartState.getInstance().setAppStartTime(appStart, appStartTime);
+
     try {
       Sentry.init(
           OptionsContainer.create(SentryAndroidOptions.class),