feat(profiling): expose continuous profiling API (#4010)

Author: armcknight

CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 ## Unreleased
 
+### Features
+
+- Continuous mode profiling (see `SentrySDK.startProfiler` and `SentryOptions.profilesSampleRate`) (#4010)
+
 ### Fixes
 
 - Proper redact SR during animation (#4289)

Samples/iOS-Swift/iOS-Swift/AppDelegate.swift

@@ -89,6 +89,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
             options.enableTimeToFullDisplayTracing = true
             options.enablePerformanceV2 = true
             options.enableMetrics = !args.contains("--disable-metrics")
+            options.profilesSampleRate = ProcessInfo.processInfo.arguments.contains("--io.sentry.enable-continuous-profiling") ? nil : 1
 
             options.add(inAppInclude: "iOS_External")
 

Sources/Sentry/Public/SentryOptions.h

@@ -466,24 +466,24 @@ NS_SWIFT_NAME(Options)
 /**
  * @warning This is an experimental feature and may still have bugs.
  * Set to @c YES to run the profiler as early as possible in an app launch, before you would
- * normally have the opportunity to call @c SentrySDK.start . If enabled, the @c tracesSampleRate
- * and @c profilesSampleRate are persisted to disk and read on the next app launch to decide whether
- * to profile that launch.
- * @see @c tracesSampler and @c profilesSampler for more information on how they work for this
- * feature.
+ * normally have the opportunity to call @c SentrySDK.start . If @c profilesSampleRate is nonnull,
+ * the @c tracesSampleRate and @c profilesSampleRate are persisted to disk and read on the next app
+ * launch to decide whether to profile that launch.
+ * @warning If @c profilesSampleRate is @c nil then a continuous profile will be started on every
+ * launch; if you desire sampling profiled launches, you must compute your own sample rate to decide
+ * whether to set this property to @c YES or @c NO .
  * @note Profiling is automatically disabled if a thread sanitizer is attached.
  */
 @property (nonatomic, assign) BOOL enableAppLaunchProfiling;
 
 /**
  * @note Profiling is not supported on watchOS or tvOS.
  * Indicates the percentage profiles being sampled out of the sampled transactions.
- * @note The default is @c 0.
  * @note The value needs to be >= @c 0.0 and \<= @c 1.0. When setting a value out of range
- * the SDK sets it to the default of @c 0.
- * This property is dependent on @c tracesSampleRate -- if @c tracesSampleRate is @c 0 (default),
- * no profiles will be collected no matter what this property is set to. This property is
- * used to undersample profiles *relative to* @c tracesSampleRate .
+ * the SDK sets it to @c 0. When set to a valid nonnull value, this property is dependent on
+ * @c tracesSampleRate -- if @c tracesSampleRate is @c 0 (default), no profiles will be collected no
+ * matter what this property is set to. This property is used to undersample profiles *relative to*
+ * @c tracesSampleRate .
  * @note Setting this value to @c nil enables an experimental new profiling mode, called continuous
  * profiling. This allows you to start and stop a profiler any time with @c SentrySDK.startProfiler
  * and @c SentrySDK.stopProfiler, which can run with no time limit, periodically uploading profiling
@@ -493,6 +493,9 @@ NS_SWIFT_NAME(Options)
  * automatically started for app launches. If you wish to sample them, you must do so at the
  * callsites where you use the API or configure launch profiling. Continuous profiling is not
  * automatically started for performance transactions as was the previous version of profiling.
+ * @seealso https://docs.sentry.io/platforms/apple/profiling/ for more information about the
+ * different profiling modes.
+ * @note The default is @c nil (which implies continuous profiling mode).
  * @warning The new continuous profiling mode is experimental and may still contain bugs.
  * @note Profiling is automatically disabled if a thread sanitizer is attached.
  */

Sources/Sentry/Public/SentrySDK.h

@@ -353,6 +353,26 @@ SENTRY_NO_INIT
 
 #endif
 
+#if SENTRY_TARGET_PROFILING_SUPPORTED
+/**
+ * Start a new continuous profiling session if one is not already running.
+ * @note Unlike trace-based profiling, continuous profiling does not take into account @c
+ * SentryOptions.profilesSampleRate ; a call to this method will always start a profile if one is
+ * not already running. This includes app launch profiles configured with @c
+ * SentryOptions.enableAppLaunchProfiling .
+ * @warning Continuous profiling mode is experimental and may still contain bugs.
+ * @seealso https://docs.sentry.io/platforms/apple/guides/ios/profiling/#continuous-profiling
+ */
++ (void)startProfiler;
+
+/**
+ * Stop a continuous profiling session if there is one ongoing.
+ * @warning Continuous profiling mode is experimental and may still contain bugs.
+ * @seealso https://docs.sentry.io/platforms/apple/guides/ios/profiling/#continuous-profiling
+ */
++ (void)stopProfiler;
+#endif // SENTRY_TARGET_PROFILING_SUPPORTED
+
 @end
 
 NS_ASSUME_NONNULL_END

Sources/Sentry/include/SentrySDK+Private.h

@@ -52,22 +52,6 @@ SentrySDK ()
  */
 + (void)captureEnvelope:(SentryEnvelope *)envelope;
 
-#if SENTRY_TARGET_PROFILING_SUPPORTED
-/**
- * Start a new continuous profiling session if one is not already running.
- * @seealso https://docs.sentry.io/platforms/apple/profiling/
- */
-+ (void)startProfiler;
-
-/**
- * Stop a continuous profiling session if there is one ongoing. This doesn't immediately
- * stop the profiler, rather, the current profiling chunk timer will be allowed to expire and will
- * not be renewed afterwards.
- * @seealso https://docs.sentry.io/platforms/apple/profiling/
- */
-+ (void)stopProfiler;
-#endif // SENTRY_TARGET_PROFILING_SUPPORTED
-
 @end
 
 NS_ASSUME_NONNULL_END

Sources/Sentry/include/SentrySampleDecision+Private.h

@@ -1,5 +1,7 @@
 #import <Foundation/Foundation.h>
 
+#import "SentrySampleDecision.h"
+
 /**
  Returns the value to use when serializing a SentrySampleDecision.
  */

Tests/SentryTests/Integrations/Performance/FramesTracking/SentryFramesTrackerTests.swift

@@ -33,6 +33,11 @@ class SentryFramesTrackerTests: XCTestCase {
         fixture = Fixture()
     }
 
+    override func tearDown() {
+        super.tearDown()
+        clearTestState()
+    }
+
     func testIsNotRunning_WhenNotStarted() {
         XCTAssertFalse(self.fixture.sut.isRunning)
     }

Tests/SentryTests/SentryOptionsTest.m

@@ -732,7 +732,7 @@ - (void)assertDefaultValues:(SentryOptions *)options
 #    pragma clang diagnostic pop
     XCTAssertNil(options.profilesSampleRate);
     XCTAssertNil(options.profilesSampler);
-    XCTAssert([options isContinuousProfilingEnabled]);
+    XCTAssertTrue([options isContinuousProfilingEnabled]);
 #endif // SENTRY_TARGET_PROFILING_SUPPORTED
 
     XCTAssertTrue([options.spotlightUrl isEqualToString:@"http://localhost:8969/stream"]);
@@ -1151,7 +1151,7 @@ - (void)testDefaultProfilesSampleRate
     // rev
     XCTAssertFalse(options.isProfilingEnabled);
 
-    XCTAssert([options isContinuousProfilingEnabled]);
+    XCTAssertTrue([options isContinuousProfilingEnabled]);
 }
 
 - (void)testProfilesSampleRate_SetToNil
@@ -1182,6 +1182,8 @@ - (void)testProfilesSampleRateLowerBound
     options.profilesSampleRate = tooLow;
     XCTAssertEqual(options.profilesSampleRate.doubleValue, 0);
 
+    // setting an invalid sample rate effectively now enables continuous profiling, since it can let
+    // the backing variable remain nil
     XCTAssertFalse([options isContinuousProfilingEnabled]);
 }
 
@@ -1200,6 +1202,8 @@ - (void)testProfilesSampleRateUpperBound
     options.profilesSampleRate = tooLow;
     XCTAssertEqual(options.profilesSampleRate.doubleValue, 0);
 
+    // setting an invalid sample rate effectively now enables continuous profiling, since it can let
+    // the backing variable remain nil
     XCTAssertFalse([options isContinuousProfilingEnabled]);
 }
 
@@ -1212,7 +1216,7 @@ - (void)testIsProfilingEnabled_NothingSet_IsDisabled
     XCTAssertFalse(options.isProfilingEnabled);
 
     XCTAssertNil(options.profilesSampleRate);
-    XCTAssert([options isContinuousProfilingEnabled]);
+    XCTAssertTrue([options isContinuousProfilingEnabled]);
 }
 
 - (void)testIsProfilingEnabled_ProfilesSampleRateSetToZero_IsDisabled
@@ -1311,14 +1315,14 @@ - (void)testDefaultProfilesSampler
 {
     SentryOptions *options = [self getValidOptions:@{}];
     XCTAssertNil(options.profilesSampler);
-    XCTAssert([options isContinuousProfilingEnabled]);
+    XCTAssertTrue([options isContinuousProfilingEnabled]);
 }
 
 - (void)testGarbageProfilesSampler_ReturnsNil
 {
     SentryOptions *options = [self getValidOptions:@{ @"profilesSampler" : @"fault" }];
     XCTAssertNil(options.profilesSampler);
-    XCTAssert([options isContinuousProfilingEnabled]);
+    XCTAssertTrue([options isContinuousProfilingEnabled]);
 }
 
 #endif // SENTRY_TARGET_PROFILING_SUPPORTED

Tests/SentryTests/SentrySDKTests.swift

@@ -423,17 +423,18 @@ class SentrySDKTests: XCTestCase {
     func testStartingContinuousProfilerWithSampleRateZero() throws {
         givenSdkWithHub()
 
-        // nil is the default value for profilesSampleRate, so we don't have to explicitly set it on the fixture
-        XCTAssertNil(fixture.options.profilesSampleRate)
+        fixture.options.profilesSampleRate = 0
+        XCTAssertEqual(try XCTUnwrap(fixture.options.profilesSampleRate).doubleValue, 0)
+
         XCTAssertFalse(SentryContinuousProfiler.isCurrentlyProfiling())
         SentrySDK.startProfiler()
-        XCTAssert(SentryContinuousProfiler.isCurrentlyProfiling())
+        XCTAssertFalse(SentryContinuousProfiler.isCurrentlyProfiling())
     }
 
     func testStartingContinuousProfilerWithSampleRateNil() throws {
         givenSdkWithHub()
 
-        fixture.options.profilesSampleRate = nil
+        // nil is the default initial value for profilesSampleRate, so we don't have to explicitly set it on the fixture
         XCTAssertFalse(SentryContinuousProfiler.isCurrentlyProfiling())
         SentrySDK.startProfiler()
         XCTAssert(SentryContinuousProfiler.isCurrentlyProfiling())

Tests/SentryTests/Transaction/SentryTransactionTests.swift

@@ -47,6 +47,11 @@ class SentryTransactionTests: XCTestCase {
         super.setUp()
         fixture = Fixture()
     }
+    
+    override func tearDown() {
+        super.tearDown()
+        clearTestState()
+    }
 
     func testSerializeMeasurements_NoMeasurements() {
         let actual = fixture.getTransaction().serialize()
@@ -223,7 +228,8 @@ class SentryTransactionTests: XCTestCase {
 
 #if os(iOS) || os(macOS) || targetEnvironment(macCatalyst)
     func testTransactionWithContinuousProfile() throws {
-        SentrySDK.setStart(Options())
+        let options = Options()
+        SentrySDK.setStart(options)
         let transaction = fixture.getTransaction()
         SentryContinuousProfiler.start()
         let profileId = try XCTUnwrap(SentryContinuousProfiler.profiler()?.profilerId.sentryIdString)