Merge pull request #1940 from DataDog/ganeshnj/feat/clear-feature-sto…

…rage-data

RUM-5084 feat: add ability to clear data in feature data storage

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
 
 - [FEATURE] Enable DatadogCore, DatadogLogs and DatadogTrace to compile on watchOS platform. See [#1918][] (Thanks [@jfiser-paylocity][]) [#1946][] 
+- [IMPROVEMENT] Ability to clear feature data storage using `clearAllData` API. See [#1940][]
 
 # 2.14.1 / 09-07-2024
 
@@ -721,6 +722,7 @@ Release `2.0` introduces breaking changes. Follow the [Migration Guide](MIGRATIO
 [#1938]: https://github.com/DataDog/dd-sdk-ios/pull/1938
 [#1947]: https://github.com/DataDog/dd-sdk-ios/pull/1947
 [#1948]: https://github.com/DataDog/dd-sdk-ios/pull/1948
+[#1940]: https://github.com/DataDog/dd-sdk-ios/pull/1940
 [@00fa9a]: https://github.com/00FA9A
 [@britton-earnin]: https://github.com/Britton-Earnin
 [@hengyu]: https://github.com/Hengyu

DatadogCore/Sources/Core/DataStore/FeatureDataStore.swift

@@ -9,7 +9,7 @@ import DatadogInternal
 
 /// A concrete implementation of the `DataStore` protocol using file storage.
 internal final class FeatureDataStore: DataStore {
-    private enum Constants {
+    enum Constants {
         /// The version of this data store implementation.
         /// If a breaking change is introduced to the format of managed files, the version must be upgraded and old data should be deleted.
         static let dataStoreVersion = 1
@@ -35,7 +35,7 @@ internal final class FeatureDataStore: DataStore {
     ) {
         self.feature = feature
         self.coreDirectory = directory
-        self.directoryPath = "\(Constants.dataStoreVersion)/" + feature
+        self.directoryPath = coreDirectory.getDataStorePath(forFeatureNamed: feature)
         self.queue = queue
         self.telemetry = telemetry
     }
@@ -87,6 +87,18 @@ internal final class FeatureDataStore: DataStore {
         }
     }
 
+    func clearAllData() {
+        queue.async {
+            do {
+                let directory = try self.coreDirectory.coreDirectory.subdirectory(path: self.directoryPath)
+                try directory.deleteAllFiles()
+            } catch let error {
+                DD.logger.error("[Data Store] Error on clearing all data for `\(self.feature)`", error: error)
+                self.telemetry.error("[Data Store] Error on clearing all data for `\(self.feature)`", error: DDError(error: error))
+            }
+        }
+    }
+
     // MARK: - Persistence
 
     private func write(data: Data, forKey key: String, version: DataStoreKeyVersion) throws {

DatadogCore/Sources/Core/DatadogCore.swift

@@ -53,10 +53,7 @@ internal final class DatadogCore {
 
     /// Registry for Features.
     @ReadWriteLock
-    private(set) var stores: [String: (
-        storage: FeatureStorage,
-        upload: FeatureUpload
-    )] = [:]
+    private(set) var stores: [String: (storage: FeatureStorage, upload: FeatureUpload)] = [:]
 
     /// Registry for Features.
     @ReadWriteLock
@@ -171,6 +168,7 @@ internal final class DatadogCore {
     /// Clears all data that has not already yet been uploaded Datadog servers.
     func clearAllData() {
         allStorages.forEach { $0.clearAllData() }
+        allDataStores.forEach { $0.clearAllData() }
     }
 
     /// Adds a message receiver to the bus.
@@ -197,6 +195,13 @@ internal final class DatadogCore {
         stores.values.map { $0.upload }
     }
 
+    private var allDataStores: [DataStore] {
+        features.values.compactMap { feature in
+            let featureType = type(of: feature) as DatadogFeature.Type
+            return scope(for: featureType).dataStore
+        }
+    }
+
     /// Awaits completion of all asynchronous operations, forces uploads (without retrying) and deinitializes
     /// this instance of the SDK. It **blocks the caller thread**.
     ///

DatadogCore/Sources/Core/Storage/Directories.swift

@@ -35,11 +35,22 @@ internal struct CoreDirectory {
             authorized: try coreDirectory.createSubdirectory(path: "\(name)/v2")
         )
     }
+
+    /// Obtains the path to the data store for given Feature.
+    ///
+    /// Note: `FeatureDataStore` directory is created on-demand which may happen before `FeatureDirectories` are created.
+    /// Hence, this method only returns the path and let the caller decide if the directory should be created.
+    ///
+    /// - Parameter name: The given Feature name.
+    /// - Returns: The path to the data store for given Feature.
+    func getDataStorePath(forFeatureNamed name: String) -> String {
+        return "\(FeatureDataStore.Constants.dataStoreVersion)/" + name
+    }
 }
 
 internal extension CoreDirectory {
     /// Creates the core directory.
-    /// 
+    ///
     /// - Parameters:
     ///   - osDirectory: the root OS directory (`/Library/Caches`) to create core directory inside.
     ///   - instanceName: The core instance name.

DatadogCore/Sources/Core/Storage/Files/File.swift

@@ -48,7 +48,7 @@ private enum FileError: Error {
 
 /// An immutable `struct` designed to provide optimized and thread safe interface for file manipulation.
 /// It doesn't own the file, which means the file presence is not guaranteed - the file can be deleted by OS at any time (e.g. due to memory pressure).
-internal struct File: WritableFile, ReadableFile, FileProtocol {
+internal struct File: WritableFile, ReadableFile, FileProtocol, Equatable {
     let url: URL
     let name: String
 

DatadogCore/Tests/Datadog/DatadogTests.swift

@@ -336,7 +336,16 @@ class DatadogTests: XCTestCase {
             try core.directory.getFeatureDirectories(forFeatureNamed: "tracing"),
         ]
 
-        let allDirectories: [Directory] = featureDirectories.flatMap { [$0.authorized, $0.unauthorized] }
+        let scope = core.scope(for: TraceFeature.self)
+        scope.dataStore.setValue("foo".data(using: .utf8)!, forKey: "bar")
+
+        // Wait for async clear completion in all features:
+        core.readWriteQueue.sync {}
+        let tracingDataStoreDir = try core.directory.coreDirectory.subdirectory(path: core.directory.getDataStorePath(forFeatureNamed: "tracing"))
+        XCTAssertTrue(tracingDataStoreDir.hasFile(named: "bar"))
+
+        var allDirectories: [Directory] = featureDirectories.flatMap { [$0.authorized, $0.unauthorized] }
+        allDirectories.append(.init(url: tracingDataStoreDir.url))
         try allDirectories.forEach { directory in _ = try directory.createFile(named: .mockRandom()) }
 
         // When
@@ -346,8 +355,11 @@ class DatadogTests: XCTestCase {
         core.readWriteQueue.sync {}
 
         // Then
-        let newNumberOfFiles = try allDirectories.reduce(0, { acc, nextDirectory in return try acc + nextDirectory.files().count })
-        XCTAssertEqual(newNumberOfFiles, 0, "All files must be removed")
+        let files: [File] = allDirectories.reduce([], { acc, nextDirectory in
+            let next = try? nextDirectory.files()
+            return acc + (next ?? [])
+        })
+        XCTAssertEqual(files, [], "All files must be removed")
 
         Datadog.flushAndDeinitialize()
     }

DatadogInternal/Sources/DataStore/DataStore.swift

@@ -61,6 +61,12 @@ public protocol DataStore {
     ///
     /// - Parameter key: The unique identifier for the value to be deleted. Must be a valid file name, as it will be persisted in files.
     func removeValue(forKey key: String)
+
+    /// Clears all data that has not already yet been uploaded Datadog servers.
+    ///
+    /// Note: This may impact the SDK's ability to detect App Hangs and Watchdog Terminations
+    /// or other features that rely on data persisted in the data store.
+    func clearAllData()
 }
 
 public extension DataStore {
@@ -83,4 +89,6 @@ public struct NOPDataStore: DataStore {
     public func value(forKey key: String, callback: @escaping (DataStoreValueResult) -> Void) {}
     /// no-op
     public func removeValue(forKey key: String) {}
+    /// no-op
+    public func clearAllData() {}
 }

TestUtilities/Mocks/DataStoreMock.swift

@@ -18,15 +18,19 @@ public class DataStoreMock: DataStore {
     public func setValue(_ value: Data, forKey key: String, version: DataStoreKeyVersion) {
         storage[key] = .value(value, version)
     }
-    
+
     public func value(forKey key: String, callback: @escaping (DataStoreValueResult) -> Void) {
         callback(storage[key] ?? .noValue)
     }
-    
+
     public func removeValue(forKey key: String) {
         storage[key] = nil
     }
-
+
+    public func clearAllData() {
+        storage.removeAll()
+    }
+
     // MARK: - Side Effects Observation
 
     public func value(forKey key: String) -> DataStoreValueResult? {