feat: Add extra app start span (#1952)

Add __mod_init_func hook which gets called before main. With
this info we can add one more app start span.

Author: philipphofmann

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Features
 
+- feat: Add extra app start span (#1952)
 - Add enableAutoBreadcrumbTracking option (#1958)
 
 ### Fixes
@@ -40,7 +41,7 @@
 ## 7.18.0
 
 ### Features
- 
+
 - Replace tracestate header with baggage (#1867)
 
 ### Fixes

Samples/tvOS-Swift/tvOS-Swift/ContentView.swift

@@ -85,6 +85,7 @@ struct ContentView: View {
             Button(action: captureMessageAction) {
                 Text("Capture Message")
             }
+            .accessibility(identifier: "captureMessageButton")
 
             Button(action: captureUserFeedbackAction) {
                 Text("Capture User Feedback")

Samples/tvOS-Swift/tvOS-SwiftUITests/LaunchUITests.swift

@@ -1,14 +1,30 @@
 import XCTest
 
 class LaunchUITests: XCTestCase {
+    
+    private let app: XCUIApplication = XCUIApplication()
 
     override func setUpWithError() throws {
         try super.setUpWithError()
         continueAfterFailure = false
+        
+        app.launch()
+    }
+    
+    override func tearDown() {
+        app.terminate()
+        super.tearDown()
     }
 
     func testLaunch() throws {
-        let app = XCUIApplication()
-        app.launch()
+        XCTAssertTrue(app.buttons["captureMessageButton"].waitForExistence(), "Home Screen doesn't exist.")
+    }
+}
+
+extension XCUIElement {
+
+    @discardableResult
+    func waitForExistence() -> Bool {
+        self.waitForExistence(timeout: TimeInterval(10))
     }
 }

Sources/Sentry/Public/SentryAppStartMeasurement.h

@@ -18,7 +18,20 @@ SENTRY_NO_INIT
               appStartTimestamp:(NSDate *)appStartTimestamp
                        duration:(NSTimeInterval)duration
            runtimeInitTimestamp:(NSDate *)runtimeInitTimestamp
-    didFinishLaunchingTimestamp:(NSDate *)didFinishLaunchingTimestamp;
+    didFinishLaunchingTimestamp:(NSDate *)didFinishLaunchingTimestamp
+    DEPRECATED_MSG_ATTRIBUTE("Use "
+                             "initWithType:appStartTimestamp:duration:mainTimestamp:"
+                             "runtimeInitTimestamp:didFinishLaunchingTimestamp instead.");
+
+/**
+ * Initializes SentryAppStartMeasurement with the given parameters.
+ */
+- (instancetype)initWithType:(SentryAppStartType)type
+                appStartTimestamp:(NSDate *)appStartTimestamp
+                         duration:(NSTimeInterval)duration
+             runtimeInitTimestamp:(NSDate *)runtimeInitTimestamp
+    moduleInitializationTimestamp:(NSDate *)moduleInitializationTimestamp
+      didFinishLaunchingTimestamp:(NSDate *)didFinishLaunchingTimestamp;
 
 /**
  * The type of the app start.
@@ -41,6 +54,11 @@ SENTRY_NO_INIT
  */
 @property (readonly, nonatomic, strong) NSDate *runtimeInitTimestamp;
 
+/**
+ * When application main function is called.
+ */
+@property (readonly, nonatomic, strong) NSDate *moduleInitializationTimestamp;
+
 /**
  * When OS posts UIApplicationDidFinishLaunchingNotification.
  */

Sources/Sentry/SentryAppStartMeasurement.m

@@ -1,4 +1,5 @@
 #import "SentryAppStartMeasurement.h"
+#import "NSDate+SentryExtras.h"
 #import <Foundation/Foundation.h>
 
 @implementation SentryAppStartMeasurement
@@ -8,12 +9,28 @@ - (instancetype)initWithType:(SentryAppStartType)type
                        duration:(NSTimeInterval)duration
            runtimeInitTimestamp:(NSDate *)runtimeInitTimestamp
     didFinishLaunchingTimestamp:(NSDate *)didFinishLaunchingTimestamp
+{
+    return [self initWithType:type
+                    appStartTimestamp:appStartTimestamp
+                             duration:duration
+                 runtimeInitTimestamp:runtimeInitTimestamp
+        moduleInitializationTimestamp:[NSDate dateWithTimeIntervalSince1970:0]
+          didFinishLaunchingTimestamp:didFinishLaunchingTimestamp];
+}
+
+- (instancetype)initWithType:(SentryAppStartType)type
+                appStartTimestamp:(NSDate *)appStartTimestamp
+                         duration:(NSTimeInterval)duration
+             runtimeInitTimestamp:(NSDate *)runtimeInitTimestamp
+    moduleInitializationTimestamp:(NSDate *)moduleInitializationTimestamp
+      didFinishLaunchingTimestamp:(NSDate *)didFinishLaunchingTimestamp
 {
     if (self = [super init]) {
         _type = type;
         _appStartTimestamp = appStartTimestamp;
         _duration = duration;
         _runtimeInitTimestamp = runtimeInitTimestamp;
+        _moduleInitializationTimestamp = moduleInitializationTimestamp;
         _didFinishLaunchingTimestamp = didFinishLaunchingTimestamp;
     }
 

Sources/Sentry/SentryAppStartTracker.m

@@ -176,12 +176,13 @@ - (void)buildAppStartMeasurement
             appStartDuration = 0;
         }
 
-        SentryAppStartMeasurement *appStartMeasurement =
-            [[SentryAppStartMeasurement alloc] initWithType:appStartType
-                                          appStartTimestamp:self.sysctl.processStartTimestamp
-                                                   duration:appStartDuration
-                                       runtimeInitTimestamp:runtimeInit
-                                didFinishLaunchingTimestamp:self.didFinishLaunchingTimestamp];
+        SentryAppStartMeasurement *appStartMeasurement = [[SentryAppStartMeasurement alloc]
+                             initWithType:appStartType
+                        appStartTimestamp:self.sysctl.processStartTimestamp
+                                 duration:appStartDuration
+                     runtimeInitTimestamp:runtimeInit
+            moduleInitializationTimestamp:self.sysctl.moduleInitializationTimestamp
+              didFinishLaunchingTimestamp:self.didFinishLaunchingTimestamp];
 
         SentrySDK.appStartMeasurement = appStartMeasurement;
     };

Sources/Sentry/SentrySysctl.m

@@ -1,8 +1,37 @@
 #import "SentrySysctl.h"
 #import "SentryCrashSysCtl.h"
+#include <stdio.h>
+#include <time.h>
+
+static NSDate *moduleInitializationTimestamp;
+static NSDate *runtimeInit = nil;
+
+void
+sentryModuleInitializationHook(int argc, char **argv, char **envp)
+{
+    moduleInitializationTimestamp = [NSDate date];
+}
+/**
+ * Module initialization functions. The C++ compiler places static constructors here. For more info
+ * visit:
+ * https://github.com/aidansteele/osx-abi-macho-file-format-reference#table-2-the-sections-of-a__datasegment
+ */
+__attribute__((section("__DATA,__mod_init_func"))) typeof(sentryModuleInitializationHook) *__init
+    = sentryModuleInitializationHook;
 
 @implementation SentrySysctl
 
++ (void)load
+{
+    // Invoked whenever this class is added to the Objective-C runtime.
+    runtimeInit = [NSDate date];
+}
+
+- (NSDate *)runtimeInitTimestamp
+{
+    return runtimeInit;
+}
+
 - (NSDate *)systemBootTimestamp
 {
     struct timeval value = sentrycrashsysctl_timeval(CTL_KERN, KERN_BOOTTIME);
@@ -15,4 +44,9 @@ - (NSDate *)processStartTimestamp
     return [NSDate dateWithTimeIntervalSince1970:startTime.tv_sec + startTime.tv_usec / 1E6];
 }
 
+- (NSDate *)moduleInitializationTimestamp
+{
+    return moduleInitializationTimestamp;
+}
+
 @end

Sources/Sentry/SentryTracer.m

@@ -588,16 +588,22 @@ - (nullable SentryAppStartMeasurement *)getAppStartMeasurement
                                    description:type];
     [appStartSpan setStartTimestamp:appStartMeasurement.appStartTimestamp];
 
+    SentrySpan *premainSpan = [self buildSpan:appStartSpan.context.spanId
+                                    operation:operation
+                                  description:@"Pre Runtime Init"];
+    [premainSpan setStartTimestamp:appStartMeasurement.appStartTimestamp];
+    [premainSpan setTimestamp:appStartMeasurement.runtimeInitTimestamp];
+
     SentrySpan *runtimeInitSpan = [self buildSpan:appStartSpan.context.spanId
                                         operation:operation
-                                      description:@"Pre main"];
-    [runtimeInitSpan setStartTimestamp:appStartMeasurement.appStartTimestamp];
-    [runtimeInitSpan setTimestamp:appStartMeasurement.runtimeInitTimestamp];
+                                      description:@"Runtime Init to Pre Main Initializers"];
+    [runtimeInitSpan setStartTimestamp:appStartMeasurement.runtimeInitTimestamp];
+    [runtimeInitSpan setTimestamp:appStartMeasurement.moduleInitializationTimestamp];
 
     SentrySpan *appInitSpan = [self buildSpan:appStartSpan.context.spanId
                                     operation:operation
                                   description:@"UIKit and Application Init"];
-    [appInitSpan setStartTimestamp:appStartMeasurement.runtimeInitTimestamp];
+    [appInitSpan setStartTimestamp:appStartMeasurement.moduleInitializationTimestamp];
     [appInitSpan setTimestamp:appStartMeasurement.didFinishLaunchingTimestamp];
 
     SentrySpan *frameRenderSpan = [self buildSpan:appStartSpan.context.spanId
@@ -608,7 +614,7 @@ - (nullable SentryAppStartMeasurement *)getAppStartMeasurement
 
     [appStartSpan setTimestamp:appStartEndTimestamp];
 
-    return @[ appStartSpan, runtimeInitSpan, appInitSpan, frameRenderSpan ];
+    return @[ appStartSpan, premainSpan, runtimeInitSpan, appInitSpan, frameRenderSpan ];
 }
 
 - (void)addMeasurements:(SentryTransaction *)transaction

Sources/Sentry/include/SentrySysctl.h

@@ -14,6 +14,10 @@ NS_ASSUME_NONNULL_BEGIN
 
 @property (readonly) NSDate *processStartTimestamp;
 
+@property (readonly) NSDate *runtimeInitTimestamp;
+
+@property (readonly) NSDate *moduleInitializationTimestamp;
+
 @end
 
 NS_ASSUME_NONNULL_END

Tests/SentryTests/Helper/SentrySysctlTests.swift

@@ -20,4 +20,34 @@ class SentrySysctlTests: XCTestCase {
 
         XCTAssertGreaterThan(distance, 0)
     }
+    
+    func testMainTimestamp_IsInThePast() {
+        let distance = Date().timeIntervalSince(sut.moduleInitializationTimestamp)
+
+        XCTAssertGreaterThan(distance, 0)
+    }
+    
+    func testMainTimestamp_IsBiggerThan_ProcessStartTime() {
+        let distance = sut.moduleInitializationTimestamp.timeIntervalSince(sut.processStartTimestamp)
+
+        XCTAssertGreaterThan(distance, 0)
+    }
+    
+    func testMainTimestamp_IsBiggerThan_RuntimeInitTimestamp() {
+        let distance = sut.moduleInitializationTimestamp.timeIntervalSince(sut.runtimeInitTimestamp)
+
+        XCTAssertGreaterThan(distance, 0)
+    }
+    
+    func testRuntimeInitTimestamp_IsBiggerThan_ProcessStartTimestamp() {
+        let distance = sut.runtimeInitTimestamp.timeIntervalSince(sut.processStartTimestamp)
+
+        XCTAssertGreaterThan(distance, 0)
+    }
+    
+    func testRuntimeInitTimestamp_IsInThePast() {
+        let distance = Date().timeIntervalSince(sut.runtimeInitTimestamp)
+
+        XCTAssertGreaterThan(distance, 0)
+    }
 }