App start: Add spans to first transaction

CHANGELOG.md

@@ -2,8 +2,9 @@
 
 ## Unreleased
 
-### Feature
+### Features
 
+- Adds app start spans to first transaction ([#2009](https://github.com/getsentry/sentry-dart/pull/2009))
 - Set snapshot to `true` when Sentry attaches a stacktrace ([#2000](https://github.com/getsentry/sentry-dart/pull/2000)) 
   - This may change grouping
 

flutter/android/src/main/kotlin/io/sentry/flutter/SentryFlutterPlugin.kt

@@ -36,8 +36,11 @@ class SentryFlutterPlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
 
   private var activity: WeakReference<Activity>? = null
   private var framesTracker: ActivityFramesTracker? = null
+  private var pluginRegistrationTime: Long? = null
 
   override fun onAttachedToEngine(flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
+    pluginRegistrationTime = System.currentTimeMillis()
+
     context = flutterPluginBinding.applicationContext
     channel = MethodChannel(flutterPluginBinding.binaryMessenger, "sentry_flutter")
     channel.setMethodCallHandler(this)
@@ -137,6 +140,7 @@ class SentryFlutterPlugin : FlutterPlugin, MethodCallHandler, ActivityAware {
     } else {
       val appStartTimeMillis = DateUtils.nanosToMillis(appStartTime.nanoTimestamp().toDouble())
       val item = mapOf<String, Any?>(
+        "pluginRegistrationTime" to pluginRegistrationTime,
         "appStartTime" to appStartTimeMillis,
         "isColdStart" to isColdStart,
       )

flutter/ios/Classes/SentryFlutterPluginApple.swift

@@ -26,7 +26,11 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
 #endif
     }
 
+    private static var pluginRegistrationTime: Int64 = 0
+
     public static func register(with registrar: FlutterPluginRegistrar) {
+        pluginRegistrationTime = Int64(Date().timeIntervalSince1970 * 1000)
+
 #if os(iOS)
         let channel = FlutterMethodChannel(name: "sentry_flutter", binaryMessenger: registrar.messenger())
 #elseif os(macOS)
@@ -387,6 +391,7 @@ public class SentryFlutterPluginApple: NSObject, FlutterPlugin {
         let isColdStart = appStartMeasurement.type == .cold
 
         let item: [String: Any] = [
+            "pluginRegistrationTime": SentryFlutterPluginApple.pluginRegistrationTime,
             "appStartTime": appStartTime,
             "isColdStart": isColdStart
         ]

flutter/lib/src/event_processor/native_app_start_event_processor.dart

@@ -1,16 +1,24 @@
-import 'dart:async';
+// ignore_for_file: invalid_use_of_internal_member
 
-import 'package:sentry/sentry.dart';
+import 'dart:async';
 
+import '../../sentry_flutter.dart';
 import '../integrations/integrations.dart';
 import '../native/sentry_native.dart';
 
+// ignore: implementation_imports
+import 'package:sentry/src/sentry_tracer.dart';
+
 /// EventProcessor that enriches [SentryTransaction] objects with app start
 /// measurement.
 class NativeAppStartEventProcessor implements EventProcessor {
   final SentryNative _native;
+  final Hub _hub;
 
-  NativeAppStartEventProcessor(this._native);
+  NativeAppStartEventProcessor(
+    this._native, {
+    Hub? hub,
+  }) : _hub = hub ?? HubAdapter();
 
   @override
   Future<SentryEvent?> apply(SentryEvent event, Hint hint) async {
@@ -25,6 +33,82 @@ class NativeAppStartEventProcessor implements EventProcessor {
       event.measurements[measurement.name] = measurement;
       _native.didAddAppStartMeasurement = true;
     }
+
+    if (appStartInfo != null) {
+      await _attachAppStartSpans(appStartInfo, event.tracer);
+    }
+
     return event;
   }
+
+  Future<void> _attachAppStartSpans(
+      AppStartInfo appStartInfo, SentryTracer transaction) async {
+    final transactionTraceId = transaction.context.traceId;
+
+    final appStartSpan = await _createAndFinishSpan(
+        tracer: transaction,
+        operation: appStartInfo.appStartTypeOperation,
+        description: appStartInfo.appStartTypeDescription,
+        parentSpanId: transaction.context.spanId,
+        traceId: transactionTraceId,
+        startTimestamp: appStartInfo.start,
+        endTimestamp: appStartInfo.end);
+
+    final pluginRegistrationSpan = await _createAndFinishSpan(
+        tracer: transaction,
+        operation: appStartInfo.appStartTypeOperation,
+        description: appStartInfo.pluginRegistrationDescription,
+        parentSpanId: appStartSpan.context.spanId,
+        traceId: transactionTraceId,
+        startTimestamp: appStartInfo.start,
+        endTimestamp: appStartInfo.pluginRegistration);
+
+    final mainIsolateSetupSpan = await _createAndFinishSpan(
+        tracer: transaction,
+        operation: appStartInfo.appStartTypeOperation,
+        description: appStartInfo.mainIsolateSetupDescription,
+        parentSpanId: appStartSpan.context.spanId,
+        traceId: transactionTraceId,
+        startTimestamp: appStartInfo.pluginRegistration,
+        endTimestamp: appStartInfo.mainIsolateStart);
+
+    final firstFrameRenderSpan = await _createAndFinishSpan(
+        tracer: transaction,
+        operation: appStartInfo.appStartTypeOperation,
+        description: appStartInfo.firstFrameRenderDescription,
+        parentSpanId: appStartSpan.context.spanId,
+        traceId: transactionTraceId,
+        startTimestamp: SentryFlutter.mainIsolateStartTime,
+        endTimestamp: appStartInfo.end);
+
+    transaction.children.addAll([
+      appStartSpan,
+      pluginRegistrationSpan,
+      mainIsolateSetupSpan,
+      firstFrameRenderSpan
+    ]);
+  }
+
+  Future<SentrySpan> _createAndFinishSpan({
+    required SentryTracer tracer,
+    required String operation,
+    required String description,
+    required SpanId? parentSpanId,
+    required SentryId? traceId,
+    required DateTime startTimestamp,
+    required DateTime endTimestamp,
+  }) async {
+    final span = SentrySpan(
+        tracer,
+        SentrySpanContext(
+          operation: operation,
+          description: description,
+          parentSpanId: parentSpanId,
+          traceId: traceId,
+        ),
+        _hub,
+        startTimestamp: startTimestamp);
+    await span.finish(endTimestamp: endTimestamp);
+    return span;
+  }
 }

flutter/lib/src/integrations/native_app_start_integration.dart

@@ -53,7 +53,11 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
     if (isIntegrationTest) {
       final appStartInfo = AppStartInfo(AppStartType.cold,
           start: DateTime.now(),
-          end: DateTime.now().add(const Duration(milliseconds: 100)));
+          end: DateTime.now().add(const Duration(milliseconds: 100)),
+          pluginRegistration:
+              DateTime.now().add(const Duration(milliseconds: 50)),
+          mainIsolateStart:
+              DateTime.now().add(const Duration(milliseconds: 60)));
       setAppStartInfo(appStartInfo);
       return;
     }
@@ -67,16 +71,22 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
         // We only assign the current time if it's not already set - this is useful in tests
         // ignore: invalid_use_of_internal_member
         _native.appStartEnd ??= options.clock();
-        final appStartEnd = _native.appStartEnd;
+        final appStartEndDateTime = _native.appStartEnd;
         final nativeAppStart = await _native.fetchNativeAppStart();
+        final pluginRegistrationTime = nativeAppStart?.pluginRegistrationTime;
+        final mainIsolateStartDateTime = SentryFlutter.mainIsolateStartTime;
 
-        if (nativeAppStart == null || appStartEnd == null) {
+        if (nativeAppStart == null ||
+            appStartEndDateTime == null ||
+            pluginRegistrationTime == null) {
           return;
         }
 
         final appStartDateTime = DateTime.fromMillisecondsSinceEpoch(
             nativeAppStart.appStartTime.toInt());
-        final duration = appStartEnd.difference(appStartDateTime);
+        final duration = appStartEndDateTime.difference(appStartDateTime);
+        final pluginRegistrationDateTime =
+            DateTime.fromMillisecondsSinceEpoch(pluginRegistrationTime);
 
         // We filter out app start more than 60s.
         // This could be due to many different reasons.
@@ -93,9 +103,11 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
 
         final appStartInfo = AppStartInfo(
             nativeAppStart.isColdStart ? AppStartType.cold : AppStartType.warm,
-            start: DateTime.fromMillisecondsSinceEpoch(
-                nativeAppStart.appStartTime.toInt()),
-            end: appStartEnd);
+            start: appStartDateTime,
+            end: appStartEndDateTime,
+            pluginRegistration: pluginRegistrationDateTime,
+            mainIsolateStart: mainIsolateStartDateTime);
+
         setAppStartInfo(appStartInfo);
       });
     }
@@ -109,16 +121,31 @@ class NativeAppStartIntegration extends Integration<SentryFlutterOptions> {
 enum AppStartType { cold, warm }
 
 class AppStartInfo {
-  AppStartInfo(this.type, {required this.start, required this.end});
+  AppStartInfo(this.type,
+      {required this.start,
+      required this.end,
+      required this.pluginRegistration,
+      required this.mainIsolateStart});
 
   final AppStartType type;
   final DateTime start;
   final DateTime end;
+  final DateTime pluginRegistration;
+  final DateTime mainIsolateStart;
+
   Duration get duration => end.difference(start);
 
   SentryMeasurement toMeasurement() {
     return type == AppStartType.cold
         ? SentryMeasurement.coldAppStart(duration)
         : SentryMeasurement.warmAppStart(duration);
   }
+
+  String get appStartTypeOperation => 'app.start.${type.name}';
+
+  String get appStartTypeDescription =>
+      type == AppStartType.cold ? 'Cold start' : 'Warm start';
+  final pluginRegistrationDescription = 'App start to plugin registration';
+  final mainIsolateSetupDescription = 'Main isolate setup';
+  final firstFrameRenderDescription = 'First frame render';
 }

flutter/lib/src/native/sentry_native.dart

@@ -129,15 +129,20 @@ class SentryNative {
 }
 
 class NativeAppStart {
-  NativeAppStart(this.appStartTime, this.isColdStart);
+  NativeAppStart(
+      {required this.appStartTime,
+      required this.pluginRegistrationTime,
+      required this.isColdStart});
 
   double appStartTime;
+  int pluginRegistrationTime;
   bool isColdStart;
 
   factory NativeAppStart.fromJson(Map<String, dynamic> json) {
     return NativeAppStart(
-      json['appStartTime'] as double,
-      json['isColdStart'] as bool,
+      appStartTime: json['appStartTime'] as double,
+      pluginRegistrationTime: json['pluginRegistrationTime'] as int,
+      isColdStart: json['isColdStart'] as bool,
     );
   }
 }

flutter/lib/src/sentry_flutter.dart

@@ -34,6 +34,11 @@ typedef FlutterOptionsConfiguration = FutureOr<void> Function(
 mixin SentryFlutter {
   static const _channel = MethodChannel('sentry_flutter');
 
+  /// Represents the time when the main isolate is set up and ready to execute.
+  @internal
+  // ignore: invalid_use_of_internal_member
+  static DateTime mainIsolateStartTime = getUtcDateTime();
+
   static Future<void> init(
     FlutterOptionsConfiguration optionsConfiguration, {
     AppRunner? appRunner,
@@ -43,6 +48,9 @@ mixin SentryFlutter {
   }) async {
     final flutterOptions = SentryFlutterOptions();
 
+    // ignore: invalid_use_of_internal_member
+    mainIsolateStartTime = flutterOptions.clock();
+
     if (platformChecker != null) {
       flutterOptions.platformChecker = platformChecker;
     }