RUMM-1322 Allow initializing DDURLSessionDelegate before starting the SDK

Datadog/Datadog.xcodeproj/project.pbxproj

@@ -260,7 +260,6 @@
 		6193DCCE251B6201009B8011 /* RUMTASScreen1ViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6193DCCD251B6201009B8011 /* RUMTASScreen1ViewController.swift */; };
 		6193DCE1251B692C009B8011 /* RUMTASTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6193DCE0251B692C009B8011 /* RUMTASTableViewController.swift */; };
 		6193DCE8251B9AB1009B8011 /* RUMTASCollectionViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6193DCE7251B9AB1009B8011 /* RUMTASCollectionViewController.swift */; };
-		61940C7C25668EC600A20043 /* URLSessionInterceptionHandler.swift in Sources */ = {isa = PBXBuildFile; fileRef = 61940C7B25668EC600A20043 /* URLSessionInterceptionHandler.swift */; };
 		6198D27124C6E3B700493501 /* RUMViewScopeTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6198D27024C6E3B700493501 /* RUMViewScopeTests.swift */; };
 		619E16D82577C1CB00B2516B /* DataProcessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = 619E16D72577C1CB00B2516B /* DataProcessor.swift */; };
 		619E16E92578E73E00B2516B /* DataMigrator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 619E16E82578E73E00B2516B /* DataMigrator.swift */; };
@@ -804,7 +803,6 @@
 		6193DCCD251B6201009B8011 /* RUMTASScreen1ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RUMTASScreen1ViewController.swift; sourceTree = "<group>"; };
 		6193DCE0251B692C009B8011 /* RUMTASTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RUMTASTableViewController.swift; sourceTree = "<group>"; };
 		6193DCE7251B9AB1009B8011 /* RUMTASCollectionViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RUMTASCollectionViewController.swift; sourceTree = "<group>"; };
-		61940C7B25668EC600A20043 /* URLSessionInterceptionHandler.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = URLSessionInterceptionHandler.swift; sourceTree = "<group>"; };
 		6198D27024C6E3B700493501 /* RUMViewScopeTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RUMViewScopeTests.swift; sourceTree = "<group>"; };
 		619E16D72577C1CB00B2516B /* DataProcessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataProcessor.swift; sourceTree = "<group>"; };
 		619E16E82578E73E00B2516B /* DataMigrator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DataMigrator.swift; sourceTree = "<group>"; };
@@ -1903,7 +1901,6 @@
 			children = (
 				613F23DC252B05BD006CD2D7 /* URLFiltering */,
 				618E1337252340810098C6B0 /* URLSessionInterceptor.swift */,
-				61940C7B25668EC600A20043 /* URLSessionInterceptionHandler.swift */,
 				61417DC52525CDDE00E2D55C /* TaskInterception.swift */,
 			);
 			path = Interception;
@@ -3293,7 +3290,6 @@
 				618715F924DC13A100FC0F69 /* RUMDataModelsMapping.swift in Sources */,
 				61C3638524361E9200C4D4E6 /* Globals.swift in Sources */,
 				E1D202EA24C065CF00D1AF3A /* ActiveSpansPool.swift in Sources */,
-				61940C7C25668EC600A20043 /* URLSessionInterceptionHandler.swift in Sources */,
 				9ED6A6B425F2901800CB2E29 /* AppStateListener.swift in Sources */,
 				61F3CDA3251118FB00C816E5 /* UIKitRUMViewsHandler.swift in Sources */,
 				61C5A88824509A0C00DA608C /* Warnings.swift in Sources */,

Datadog/Example/Scenarios/URLSession/NSURLSessionAutoInstrumentation/ObjcSendFirstPartyRequestsViewController.m

@@ -20,7 +20,7 @@ - (void)viewDidLoad {
 
     self.testScenario = SwiftGlobals.currentTestScenario;
 
-    self.session = [self.testScenario buildURLSession];
+    self.session = [self.testScenario getURLSession];
     assert(self.testScenario != nil);
 }
 

Datadog/Example/Scenarios/URLSession/NSURLSessionAutoInstrumentation/ObjcSendThirdPartyRequestsViewController.m

@@ -18,7 +18,7 @@ @implementation ObjcSendThirdPartyRequestsViewController
 - (void)viewDidLoad {
     [super viewDidLoad];
     self.testScenario = SwiftGlobals.currentTestScenario;
-    self.session = [self.testScenario buildURLSession];
+    self.session = [self.testScenario getURLSession];
     assert(self.testScenario != nil);
 }
 

Datadog/Example/Scenarios/URLSession/URLSessionAutoInstrumentation/SendFirstPartyRequestsViewController.swift

@@ -10,7 +10,7 @@ import Datadog
 
 internal class SendFirstPartyRequestsViewController: UIViewController {
     private var testScenario: URLSessionBaseScenario!
-    private lazy var session = testScenario.buildURLSession()
+    private lazy var session = testScenario.getURLSession()
 
     override func viewDidLoad() {
         super.viewDidLoad()

Datadog/Example/Scenarios/URLSession/URLSessionAutoInstrumentation/SendThirdPartyRequestsViewController.swift

@@ -10,7 +10,7 @@ import Datadog
 
 internal class SendThirdPartyRequestsViewController: UIViewController {
     private var testScenario: URLSessionBaseScenario!
-    private lazy var session = testScenario.buildURLSession()
+    private lazy var session = testScenario.getURLSession()
 
     override func viewDidLoad() {
         super.viewDidLoad()

Datadog/Example/Scenarios/URLSession/URLSessionScenarios.swift

@@ -14,9 +14,13 @@ import Datadog
 /// calls third party endpoints.
 @objc
 class URLSessionBaseScenario: NSObject {
-    /// If yes, instrumented endpoints are passed to `DDURLSessionDelegate`; otherwise, they are passed to `DatadogConfiguration.trackURLSession` method
-    @objc
-    let feedAdditionalFirstyPartyHosts: Bool
+    /// Randomizes the way of passing additional first party hosts.
+    /// If `true`, instrumented endpoints are passed to `DDURLSessionDelegate`; otherwise, they are passed to `DatadogConfiguration.trackURLSession(...)`.
+    private let feedAdditionalFirstyPartyHosts: Bool
+
+    /// Randomizes the way of creating `URLSession` instrumented with `DDURLSessionDelegate`.
+    /// If `true`, the session is created after `Datadog.initialize()`; if `false`, it's created before.
+    private let lazyInitRLSession: Bool
 
     /// The URL to custom GET resource, observed by Tracing auto instrumentation.
     @objc
@@ -38,8 +42,13 @@ class URLSessionBaseScenario: NSObject {
     @objc
     let thirdPartyURL: URL
 
+    /// Randomized value determining if the `DDURLSessionDelegate` should be initialized before (`false)` or after `Datadog.initialize()` (`true`).
+    private var ddURLSessionDelegate: DDURLSessionDelegate?
+
     override init() {
-        feedAdditionalFirstyPartyHosts = Bool.random()
+        feedAdditionalFirstyPartyHosts = .random()
+        lazyInitRLSession = .random()
+
         if ProcessInfo.processInfo.arguments.contains("IS_RUNNING_UI_TESTS") {
             let serverMockConfiguration = Environment.serverMockConfiguration()!
             customGETResourceURL = serverMockConfiguration.instrumentedEndpoints[0]
@@ -71,6 +80,13 @@ class URLSessionBaseScenario: NSObject {
                 return request
             }()
         }
+        super.init()
+
+        if lazyInitRLSession {
+            self.session = nil // it will be created on lazily, on first access from VC
+        } else {
+            self.session = createInstrumentedURLSession()
+        }
     }
 
     func configureSDK(builder: Datadog.Configuration.Builder) {
@@ -83,8 +99,18 @@ class URLSessionBaseScenario: NSObject {
         }
     }
 
+    private var session: URLSession!
+
     @objc
-    func buildURLSession() -> URLSession {
+    func getURLSession() -> URLSession {
+        if session == nil {
+            precondition(lazyInitRLSession, "The session is unavailable, but it is not configured for lazy init")
+            session = createInstrumentedURLSession()
+        }
+        return session
+    }
+
+    private func createInstrumentedURLSession() -> URLSession {
         let delegate: DDURLSessionDelegate
         if feedAdditionalFirstyPartyHosts {
             delegate = DDURLSessionDelegate(

Sources/Datadog/URLSessionAutoInstrumentation/DDURLSessionDelegate.swift

@@ -28,44 +28,22 @@ open class DDURLSessionDelegate: NSObject, URLSessionTaskDelegate, URLSessionDat
         return self
     }
 
-    var interceptor: URLSessionInterceptorType?
-    let firstPartyURLsFilter: FirstPartyURLsFilter?
+    internal var interceptor: URLSessionInterceptorType? { URLSessionAutoInstrumentation.instance?.interceptor }
+    private(set) var firstPartyURLsFilter: FirstPartyURLsFilter?
 
     @objc
     override public init() {
-        Self.datadogInitializationCheck()
         firstPartyURLsFilter = nil
-        interceptor = URLSessionAutoInstrumentation.instance?.interceptor
     }
 
     /// Automatically tracked hosts can be customized per instance with this initializer
     /// - Parameter additionalFirstPartyHosts: these hosts are tracked **in addition to** what was
     /// passed to `DatadogConfiguration.Builder` via `trackURLSession(firstPartyHosts:)`
+    ///
     /// **NOTE:** If `trackURLSession(firstPartyHosts:)` is never called, automatic tracking will **not** take place
     @objc
     public init(additionalFirstPartyHosts: Set<String>) {
-        // NOTE: RUMM-954 copy&pasting `init()` is a conscious decision.
-        // otherwise `DDURLSessionDelegateAsSuperclassTests` fails.
-        // if `init()` was made convenience and call the designated `init` below,
-        // that would result in potential breaking changes.
-        // host projects would need to change their `init()`s in subclasses.
-        // we can fix this in v2.0
-        Self.datadogInitializationCheck()
         firstPartyURLsFilter = FirstPartyURLsFilter(hosts: additionalFirstPartyHosts)
-        interceptor = URLSessionAutoInstrumentation.instance?.interceptor
-    }
-
-    private static func datadogInitializationCheck() {
-        if URLSessionAutoInstrumentation.instance?.interceptor == nil {
-            let error = ProgrammerError(
-                description: """
-                `Datadog.initialize()` must be called before initializing the `DDURLSessionDelegate` and
-                first party hosts must be specified in `Datadog.Configuration`: `trackURLSession(firstPartyHosts:)`
-                to enable network requests tracking.
-                """
-            )
-            consolePrint("\(error)")
-        }
     }
 
     open func urlSession(_ session: URLSession, task: URLSessionTask, didFinishCollecting metrics: URLSessionTaskMetrics) {

Sources/Datadog/URLSessionAutoInstrumentation/Interception/URLSessionInterceptor.swift

@@ -6,18 +6,29 @@
 
 import Foundation
 
+/// An interface for handling `URLSession` interceptions start and completion.
+internal protocol URLSessionInterceptionHandler {
+    /// Notifies the `URLSessionTask` interception start.
+    func notify_taskInterceptionStarted(interception: TaskInterception)
+    /// Notifies the `URLSessionTask` interception completion.
+    func notify_taskInterceptionCompleted(interception: TaskInterception)
+}
+
+/// An interface for processing `URLSession` task interceptions.
 internal protocol URLSessionInterceptorType: class {
     func modify(request: URLRequest, session: URLSession?) -> URLRequest
     func taskCreated(task: URLSessionTask, session: URLSession?)
     func taskMetricsCollected(task: URLSessionTask, metrics: URLSessionTaskMetrics)
     func taskReceivedData(task: URLSessionTask, data: Data)
     func taskCompleted(task: URLSessionTask, error: Error?)
+
+    var handler: URLSessionInterceptionHandler { get }
 }
 
 /// An object performing interception of requests sent with `URLSession`.
 public class URLSessionInterceptor: URLSessionInterceptorType {
     public static var shared: URLSessionInterceptor? {
-        URLSessionAutoInstrumentation.instance?.interceptor
+        URLSessionAutoInstrumentation.instance?.interceptor as? URLSessionInterceptor
     }
 
     /// Filters first party `URLs` defined by the user.

Sources/Datadog/URLSessionAutoInstrumentation/URLSessionAutoInstrumentation.swift

@@ -11,20 +11,22 @@ internal class URLSessionAutoInstrumentation {
     static var instance: URLSessionAutoInstrumentation?
 
     let swizzler: URLSessionSwizzler
-    let interceptor: URLSessionInterceptor
+    let interceptor: URLSessionInterceptorType
 
-    init?(
+    convenience init?(
         configuration: FeaturesConfiguration.URLSessionAutoInstrumentation,
         dateProvider: DateProvider,
         appStateListener: AppStateListening
     ) {
         do {
-            self.interceptor = URLSessionInterceptor(
-                configuration: configuration,
-                dateProvider: dateProvider,
-                appStateListener: appStateListener
+            self.init(
+                swizzler: try URLSessionSwizzler(),
+                interceptor: URLSessionInterceptor(
+                    configuration: configuration,
+                    dateProvider: dateProvider,
+                    appStateListener: appStateListener
+                )
             )
-            self.swizzler = try URLSessionSwizzler()
         } catch {
             consolePrint(
                 "🔥 Datadog SDK error: automatic tracking of `URLSession` requests can't be set up due to error: \(error)"
@@ -33,6 +35,11 @@ internal class URLSessionAutoInstrumentation {
         }
     }
 
+    init(swizzler: URLSessionSwizzler, interceptor: URLSessionInterceptorType) {
+        self.swizzler = swizzler
+        self.interceptor = interceptor
+    }
+
     func enable() {
         swizzler.swizzle()
     }

Tests/DatadogTests/Datadog/Mocks/URLSessionAutoInstrumentationMocks.swift

@@ -55,6 +55,26 @@ class URLSessionInterceptorMock: URLSessionInterceptorType {
         taskMetrics.append((task: task, metrics: metrics))
         onTaskMetricsCollected?(task, metrics)
     }
+
+    let handler: URLSessionInterceptionHandler = URLSessionInterceptionHandlerMock()
+}
+
+class URLSessionInterceptionHandlerMock: URLSessionInterceptionHandler {
+    var didNotifyInterceptionStart: ((TaskInterception) -> Void)?
+    var startedInterceptions: [TaskInterception] = []
+
+    func notify_taskInterceptionStarted(interception: TaskInterception) {
+        startedInterceptions.append(interception)
+        didNotifyInterceptionStart?(interception)
+    }
+
+    var didNotifyInterceptionCompletion: ((TaskInterception) -> Void)?
+    var completedInterceptions: [TaskInterception] = []
+
+    func notify_taskInterceptionCompleted(interception: TaskInterception) {
+        completedInterceptions.append(interception)
+        didNotifyInterceptionCompletion?(interception)
+    }
 }
 
 extension ResourceCompletion {