RUMM-1691 Reduce utilization of CTTelephonyNetworkInfo to mitigate CarrierInfoProvider crash

Datadog/Example/Base.lproj/Main.storyboard

@@ -320,28 +320,74 @@
                                             <constraint firstAttribute="height" constant="44" id="qZn-EW-PqZ"/>
                                         </constraints>
                                     </stackView>
-                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Rlt-GG-uem" userLabel="Vertical gap 10">
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="ghm-SJ-eBQ" userLabel="Vertical gap 10">
                                         <rect key="frame" x="0.0" y="251" width="384" height="10"/>
                                         <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                                        <constraints>
+                                            <constraint firstAttribute="height" constant="10" id="d0W-7M-BGO"/>
+                                        </constraints>
+                                    </view>
+                                    <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="STRESS TESTING:" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="hVf-hM-tBK">
+                                        <rect key="frame" x="0.0" y="261" width="384" height="13.5"/>
+                                        <fontDescription key="fontDescription" style="UICTFontTextStyleCaption1"/>
+                                        <color key="textColor" systemColor="systemGrayColor"/>
+                                        <nil key="highlightedColor"/>
+                                    </label>
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="VDB-9q-Bc1" userLabel="Vertical gap 5">
+                                        <rect key="frame" x="0.0" y="274.5" width="384" height="5"/>
+                                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
+                                        <constraints>
+                                            <constraint firstAttribute="height" constant="5" id="ObB-P8-mKh"/>
+                                        </constraints>
+                                    </view>
+                                    <stackView opaque="NO" contentMode="scaleToFill" spacing="5" translatesAutoresizingMaskIntoConstraints="NO" id="l6y-hy-nRu">
+                                        <rect key="frame" x="0.0" y="279.5" width="384" height="44"/>
+                                        <subviews>
+                                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="n8y-PP-kzI">
+                                                <rect key="frame" x="0.0" y="0.0" width="384" height="44"/>
+                                                <color key="backgroundColor" red="0.38823529410000002" green="0.17254901959999999" blue="0.65098039220000004" alpha="1" colorSpace="calibratedRGB"/>
+                                                <fontDescription key="fontDescription" style="UICTFontTextStyleBody"/>
+                                                <state key="normal" title="Keep sending ~500 logs/s for 10s">
+                                                    <color key="titleColor" white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                                    <color key="titleShadowColor" white="0.0" alpha="0.0" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                                                </state>
+                                                <userDefinedRuntimeAttributes>
+                                                    <userDefinedRuntimeAttribute type="boolean" keyPath="layer.masksToBounds" value="YES"/>
+                                                    <userDefinedRuntimeAttribute type="number" keyPath="layer.cornerRadius">
+                                                        <integer key="value" value="7"/>
+                                                    </userDefinedRuntimeAttribute>
+                                                </userDefinedRuntimeAttributes>
+                                                <connections>
+                                                    <action selector="didTapStressTest:" destination="BYZ-38-t0r" eventType="touchUpInside" id="SzO-9c-7v5"/>
+                                                </connections>
+                                            </button>
+                                        </subviews>
+                                        <constraints>
+                                            <constraint firstAttribute="height" constant="44" id="VgF-xP-icc"/>
+                                        </constraints>
+                                    </stackView>
+                                    <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Rlt-GG-uem" userLabel="Vertical gap 10">
+                                        <rect key="frame" x="0.0" y="323.5" width="384" height="10"/>
+                                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                         <constraints>
                                             <constraint firstAttribute="height" constant="10" id="oUy-Tr-5NI"/>
                                         </constraints>
                                     </view>
                                     <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="CONSOLE OUTPUT:" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="x1i-in-lYX">
-                                        <rect key="frame" x="0.0" y="261" width="384" height="13.5"/>
+                                        <rect key="frame" x="0.0" y="333.5" width="384" height="13.5"/>
                                         <fontDescription key="fontDescription" style="UICTFontTextStyleCaption1"/>
                                         <color key="textColor" systemColor="systemGrayColor"/>
                                         <nil key="highlightedColor"/>
                                     </label>
                                     <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="MU9-DG-sTJ" userLabel="Vertical gap 10">
-                                        <rect key="frame" x="0.0" y="274.5" width="384" height="10"/>
+                                        <rect key="frame" x="0.0" y="347" width="384" height="10"/>
                                         <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                         <constraints>
                                             <constraint firstAttribute="height" constant="10" id="P0L-Pu-XZ9"/>
                                         </constraints>
                                     </view>
                                     <textView clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" editable="NO" textAlignment="natural" selectable="NO" translatesAutoresizingMaskIntoConstraints="NO" id="2G0-OF-tGX">
-                                        <rect key="frame" x="0.0" y="284.5" width="384" height="459.5"/>
+                                        <rect key="frame" x="0.0" y="357" width="384" height="387"/>
                                         <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                         <color key="textColor" systemColor="systemGrayColor"/>
                                         <fontDescription key="fontDescription" type="system" pointSize="11"/>
@@ -367,6 +413,7 @@
                         <outlet property="logServiceNameTextField" destination="fGc-5E-uEZ" id="15I-2q-gUt"/>
                         <outlet property="send10xButton" destination="u78-T2-8Dx" id="EK9-y6-WQK"/>
                         <outlet property="sendOnceButton" destination="gtC-h0-4xC" id="9Cc-de-Und"/>
+                        <outlet property="stressTestButton" destination="n8y-PP-kzI" id="tKj-cc-sV9"/>
                     </connections>
                 </viewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>

Datadog/Example/Debugging/DebugLoggingViewController.swift

@@ -5,13 +5,15 @@
  */
 
 import UIKit
+import Datadog
 
 class DebugLoggingViewController: UIViewController {
     @IBOutlet weak var logLevelSegmentedControl: UISegmentedControl!
     @IBOutlet weak var logMessageTextField: UITextField!
     @IBOutlet weak var logServiceNameTextField: UITextField!
     @IBOutlet weak var sendOnceButton: UIButton!
     @IBOutlet weak var send10xButton: UIButton!
+    @IBOutlet weak var stressTestButton: UIButton!
     @IBOutlet weak var consoleTextView: UITextView!
 
     struct StructError: Error {
@@ -78,4 +80,43 @@ class DebugLoggingViewController: UIViewController {
     private func repeat10x(block: () -> Void) {
         (0..<10).forEach { _ in block() }
     }
+
+    // MARK: - Stress testing
+
+    var queues: [DispatchQueue] = []
+    var loggers: [Logger] = []
+
+    @IBAction func didTapStressTest(_ sender: Any) {
+        stressTestButton.disableFor(seconds: 10)
+
+        loggers = (0..<5).map { index in
+            return Logger.builder.set(loggerName: "stress-logger-\(index)")
+                .sendNetworkInfo(true)
+                .build()
+        }
+
+        queues = (0..<5).map { index in
+            return DispatchQueue(label: "com.datadoghq.example.stress-testing-queue\(index)")
+        }
+
+        let endDate = Date(timeIntervalSinceNow: 10) // 10s
+        zip(loggers, queues).forEach { logger, queue in
+            keepSendingLogs(on: queue, using: logger, every: 0.01, until: endDate)
+        }
+    }
+
+    private func keepSendingLogs(on queue: DispatchQueue, using logger: Logger, every timeInterval: TimeInterval, until endDate: Date) {
+        if Date() < endDate {
+            queue.asyncAfter(deadline: .now() + timeInterval) { [weak self] in
+                logger.debug(self?.randomLogMessage() ?? "")
+                self?.keepSendingLogs(on: queue, using: logger, every: timeInterval, until: endDate)
+            }
+        }
+    }
+
+    private let alphanumerics = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+
+    private func randomLogMessage() -> String {
+        return String((0..<20).map { _ in alphanumerics.randomElement()! })
+    }
 }

Sources/Datadog/Core/System/CarrierInfoProvider.swift

@@ -66,88 +66,147 @@ extension CarrierInfo.RadioAccessTechnology {
     }
 }
 
-/// An interface for the target-specific carrier info provider.
-internal protocol WrappedCarrierInfoProvider {
-    var current: CarrierInfo? { get }
-}
-
+/// Platform-agnostic carrier info provider. It wraps the platform-specific provider inside.
 internal class CarrierInfoProvider: CarrierInfoProviderType {
     /// The `CarrierInfo` provider for the current platform.
-    private let wrappedProvider: WrappedCarrierInfoProvider
-    /// Publisher for notifying observers on `CarrierInfo` change.
-    private let publisher: ValuePublisher<CarrierInfo?>
+    private let wrappedProvider: CarrierInfoProviderType
 
     convenience init() {
         #if targetEnvironment(macCatalyst)
-            self.init(
-                wrappedProvider: MacCatalystCarrierInfoProvider()
-            )
+        self.init(
+            wrappedProvider: MacCatalystCarrierInfoProvider()
+        )
         #else
-            self.init(
-                wrappedProvider: iOSCarrierInfoProvider(
-                    networkInfo: CTTelephonyNetworkInfo()
-                )
-            )
+        if #available(iOS 12.0, *) {
+            self.init(wrappedProvider: iOS12CarrierInfoProvider(networkInfo: CTTelephonyNetworkInfo()))
+        } else {
+            self.init(wrappedProvider: iOS11CarrierInfoProvider(networkInfo: CTTelephonyNetworkInfo()))
+        }
         #endif
     }
 
-    init(wrappedProvider: WrappedCarrierInfoProvider) {
+    init(wrappedProvider: CarrierInfoProviderType) {
         self.wrappedProvider = wrappedProvider
-        self.publisher = ValuePublisher(initialValue: nil)
     }
 
     var current: CarrierInfo? {
-        let nextValue = wrappedProvider.current
-        // `CarrierInfo` subscribers are notified as a side-effect of retrieving the
-        // current `CarrierInfo` value.
-        publisher.publishAsync(nextValue)
-        return nextValue
+        wrappedProvider.current
     }
 
     func subscribe<Observer: CarrierInfoObserver>(_ subscriber: Observer) where Observer.ObservedValue == CarrierInfo? {
-        publisher.subscribe(subscriber)
+        wrappedProvider.subscribe(subscriber)
     }
 }
 
 #if targetEnvironment(macCatalyst)
 
-internal struct MacCatalystCarrierInfoProvider: WrappedCarrierInfoProvider {
-    /// Carrier info is not supported on macCatalyst
+/// Dummy provider for Mac Catalyst which doesn't support carrier info.
+internal struct MacCatalystCarrierInfoProvider: CarrierInfoProviderType {
     var current: CarrierInfo? { return nil }
+    func subscribe<Observer>(_ subscriber: Observer) where Observer: ValueObserver, Observer.ObservedValue == CarrierInfo? {}
 }
 
 #else
 
-internal struct iOSCarrierInfoProvider: WrappedCarrierInfoProvider {
-    let networkInfo: CTTelephonyNetworkInfo
+/// Carrier info provider for iOS 12 and above.
+/// It reads `CarrierInfo?` from `CTTelephonyNetworkInfo` only when `CTCarrier` has changed (e.g. when the SIM card was swapped).
+@available(iOS 12, *)
+internal class iOS12CarrierInfoProvider: CarrierInfoProviderType {
+    private let networkInfo: CTTelephonyNetworkInfo
+    /// Publisher for notifying observers on `CarrierInfo` change.
+    private let publisher: ValuePublisher<CarrierInfo?>
 
-    var current: CarrierInfo? {
-        let carrier: CTCarrier?
-        let radioTechnology: String?
+    init(networkInfo: CTTelephonyNetworkInfo) {
+        self.networkInfo = networkInfo
+        self.publisher = ValuePublisher(
+            initialValue: iOS12CarrierInfoProvider.readCarrierInfo(
+                from: networkInfo,
+                cellularProviderKey: networkInfo.serviceCurrentRadioAccessTechnology?.keys.first
+            )
+        )
 
-        if #available(iOS 12, *) {
-            guard let cellularProviderKey = networkInfo.serviceCurrentRadioAccessTechnology?.keys.first else {
-                return nil
+        // The `serviceSubscriberCellularProvidersDidUpdateNotifier` block object executes on the default priority
+        // global dispatch queue when the user’s cellular provider information changes.
+        // This occurs, for example, if a user swaps the device’s SIM card with one from another provider, while the app is running.
+        // ref.: https://developer.apple.com/documentation/coretelephony/cttelephonynetworkinfo/3024512-servicesubscribercellularprovide
+        networkInfo.serviceSubscriberCellularProvidersDidUpdateNotifier = { [weak self] cellularProviderKey in
+            guard let strongSelf = self else {
+                return
             }
-            radioTechnology = networkInfo.serviceCurrentRadioAccessTechnology?[cellularProviderKey]
-            carrier = networkInfo.serviceSubscriberCellularProviders?[cellularProviderKey]
-        } else {
-            radioTechnology = networkInfo.currentRadioAccessTechnology
-            carrier = networkInfo.subscriberCellularProvider
+
+            let carrierInfo = iOS12CarrierInfoProvider.readCarrierInfo(
+                from: strongSelf.networkInfo,
+                cellularProviderKey: cellularProviderKey
+            )
+
+            // On iOS12+ `CarrierInfo` subscribers are notified on actual change to cellular provider.
+            strongSelf.publisher.publishAsync(carrierInfo)
         }
+    }
 
-        guard let radioAccessTechnology = radioTechnology,
-            let currentCTCarrier = carrier else {
-                return nil
+    private static func readCarrierInfo(from networkInfo: CTTelephonyNetworkInfo, cellularProviderKey: String?) -> CarrierInfo? {
+        guard let cellularProviderKey = cellularProviderKey,
+           let radioTechnology = networkInfo.serviceCurrentRadioAccessTechnology?[cellularProviderKey],
+           let carrier = networkInfo.serviceSubscriberCellularProviders?[cellularProviderKey] else {
+            return nil // the service is not registered on any network
         }
+        return CarrierInfo(
+            carrierName: carrier.carrierName,
+            carrierISOCountryCode: carrier.isoCountryCode,
+            carrierAllowsVOIP: carrier.allowsVOIP,
+            radioAccessTechnology: .init(ctRadioAccessTechnologyConstant: radioTechnology)
+        )
+    }
+
+    var current: CarrierInfo? {
+        publisher.currentValue
+    }
+
+    func subscribe<Observer>(_ subscriber: Observer) where Observer: ValueObserver, Observer.ObservedValue == CarrierInfo? {
+        publisher.subscribe(subscriber)
+    }
+}
+
+/// Carrier info provider for iOS 11.
+/// It reads `CarrierInfo?` from `CTTelephonyNetworkInfo` each time.
+internal class iOS11CarrierInfoProvider: CarrierInfoProviderType {
+    private let networkInfo: CTTelephonyNetworkInfo
+    /// Publisher for notifying observers on `CarrierInfo` change.
+    private let publisher: ValuePublisher<CarrierInfo?>
+
+    init(networkInfo: CTTelephonyNetworkInfo) {
+        self.networkInfo = networkInfo
+        self.publisher = ValuePublisher(
+            initialValue: iOS11CarrierInfoProvider.readCarrierInfo(from: networkInfo)
+        )
+    }
 
+    private static func readCarrierInfo(from networkInfo: CTTelephonyNetworkInfo) -> CarrierInfo? {
+        guard let radioTechnology = networkInfo.currentRadioAccessTechnology,
+              let carrier = networkInfo.subscriberCellularProvider else {
+            return nil // the service is not registered on any network
+        }
         return CarrierInfo(
-            carrierName: currentCTCarrier.carrierName,
-            carrierISOCountryCode: currentCTCarrier.isoCountryCode,
-            carrierAllowsVOIP: currentCTCarrier.allowsVOIP,
-            radioAccessTechnology: .init(ctRadioAccessTechnologyConstant: radioAccessTechnology)
+            carrierName: carrier.carrierName,
+            carrierISOCountryCode: carrier.isoCountryCode,
+            carrierAllowsVOIP: carrier.allowsVOIP,
+            radioAccessTechnology: .init(ctRadioAccessTechnologyConstant: radioTechnology)
         )
     }
+
+    var current: CarrierInfo? {
+        let carrierInfo = iOS11CarrierInfoProvider.readCarrierInfo(from: networkInfo)
+
+        // On iOS11 `CarrierInfo` subscribers are notified as a side-effect of pulling the
+        // current `CarrierInfo` value.
+        publisher.publishAsync(carrierInfo)
+
+        return carrierInfo
+    }
+
+    func subscribe<Observer>(_ subscriber: Observer) where Observer: ValueObserver, Observer.ObservedValue == CarrierInfo? {
+        publisher.subscribe(subscriber)
+    }
 }
 
 #endif

Sources/Datadog/Core/System/NetworkConnectionInfoProvider.swift

@@ -172,7 +172,7 @@ internal class iOS11NetworkConnectionInfoProvider: WrappedNetworkConnectionInfoP
     }
 }
 
-// MARK: Conversion helpers
+// MARK: - Conversion helpers
 
 extension NetworkConnectionInfo.Reachability {
     @available(iOS 12, *)