fix(project-config): add support for multiple clients (#409)

Fix ProjectConfig to support multiple clients (sdkKeys).

- full thread-safety for additional concurrency requirements
- no resource conflicts for multiple sdkKeys support

Author: jaeopt

OptimizelySwiftSDK.xcodeproj/project.pbxproj

@@ -574,6 +574,7 @@
 		6E623F0F253F9045000617D0 /* DecisionInfo.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6E623F01253F9045000617D0 /* DecisionInfo.swift */; };
 		6E636B912236C91F00AF3CEF /* Optimizely.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6EBAEB6C21E3FEF800D13AA9 /* Optimizely.framework */; };
 		6E636BA02236C96700AF3CEF /* Optimizely.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6EBAEB6C21E3FEF800D13AA9 /* Optimizely.framework */; };
+		6E6419FE265734C100C49555 /* ProjectConfigTests_MultiClients.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6E6419FD265734C100C49555 /* ProjectConfigTests_MultiClients.swift */; };
 		6E6419DA2657059700C49555 /* NotificationCenterTests_MultiClients.swift in Sources */ = {isa = PBXBuildFile; fileRef = 6E6419D92657059700C49555 /* NotificationCenterTests_MultiClients.swift */; };
 		6E6BE00B237F547200FE8274 /* optimizely_config_datafile.json in Resources */ = {isa = PBXBuildFile; fileRef = 6E6BE009237F547200FE8274 /* optimizely_config_datafile.json */; };
 		6E6BE00C237F547200FE8274 /* optimizely_config_expected.json in Resources */ = {isa = PBXBuildFile; fileRef = 6E6BE00A237F547200FE8274 /* optimizely_config_expected.json */; };
@@ -1851,6 +1852,7 @@
 		6E623F01253F9045000617D0 /* DecisionInfo.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DecisionInfo.swift; sourceTree = "<group>"; };
 		6E636B8C2236C91F00AF3CEF /* OptimizelyTests-APIs-iOS.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = "OptimizelyTests-APIs-iOS.xctest"; sourceTree = BUILT_PRODUCTS_DIR; };
 		6E636B9B2236C96700AF3CEF /* OptimizelyTests-Legacy-iOS.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = "OptimizelyTests-Legacy-iOS.xctest"; sourceTree = BUILT_PRODUCTS_DIR; };
+		6E6419FD265734C100C49555 /* ProjectConfigTests_MultiClients.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ProjectConfigTests_MultiClients.swift; sourceTree = "<group>"; };
 		6E6419D92657059700C49555 /* NotificationCenterTests_MultiClients.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationCenterTests_MultiClients.swift; sourceTree = "<group>"; };
 		6E6BE009237F547200FE8274 /* optimizely_config_datafile.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = optimizely_config_datafile.json; sourceTree = "<group>"; };
 		6E6BE00A237F547200FE8274 /* optimizely_config_expected.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = optimizely_config_expected.json; sourceTree = "<group>"; };
@@ -2238,6 +2240,7 @@
 				6E474C8C263C889E00ABDFF8 /* UserProfileServiceTests_MultiClients.swift */,
 				6EE591192649CF640013AD66 /* LoggerTests_MultiClients.swift */,
 				6EE5918D264AF44B0013AD66 /* HandlerRegistryServiceTests_MultiClients.swift */,
+				6E6419FD265734C100C49555 /* ProjectConfigTests_MultiClients.swift */,
 				6E6419D92657059700C49555 /* NotificationCenterTests_MultiClients.swift */,
 			);
 			path = "OptimizelyTests-MultiClients";
@@ -3685,6 +3688,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				6E424CEC26324B620081004A /* DefaultLogger.swift in Sources */,
+				6E6419FE265734C100C49555 /* ProjectConfigTests_MultiClients.swift in Sources */,
 				6E424CED26324B620081004A /* DefaultUserProfileService.swift in Sources */,
 				6E424CEE26324B620081004A /* DefaultEventDispatcher.swift in Sources */,
 				6E424CEF26324B620081004A /* DefaultDatafileHandler.swift in Sources */,

Podfile.lock

@@ -17,4 +17,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 8efc37b7d97fa9de16532d755b40b003d888b834
 
-COCOAPODS: 1.9.3
+COCOAPODS: 1.10.1

Sources/Data Model/ProjectConfig.swift

@@ -25,7 +25,7 @@ class ProjectConfig {
     // local runtime forcedVariations [UserId: [ExperimentId: VariationId]]
     // NOTE: experiment.forcedVariations use [ExperimentKey: VariationKey] instead of ids
 
-    var whitelistUsers = [String: [String: String]]()
+    var whitelistUsers = AtomicProperty(property: [String: [String: String]]())
 
     lazy var experimentKeyMap: [String: Experiment] = {
         var map = [String: Experiment]()
@@ -152,26 +152,30 @@ extension ProjectConfig {
 // MARK: - Persistent Data
 
 extension ProjectConfig {
-    private func whitelistUser(userId: String, experimentId: String, variationId: String) {
-        var dic = whitelistUsers[userId] ?? [String: String]()
-        dic[experimentId] = variationId
-        whitelistUsers[userId] = dic
+    func whitelistUser(userId: String, experimentId: String, variationId: String) {
+        whitelistUsers.performAtomic { whitelist in
+            var dict = whitelist[userId] ?? [String: String]()
+            dict[experimentId] = variationId
+            whitelist[userId] = dict
+        }
     }
 
-    private func removeFromWhitelist(userId: String, experimentId: String) {
-        self.whitelistUsers[userId]?.removeValue(forKey: experimentId)
+    func removeFromWhitelist(userId: String, experimentId: String) {
+        whitelistUsers.performAtomic { whitelist in
+            whitelist[userId]?.removeValue(forKey: experimentId)
+        }
     }
 
-    private func getWhitelistedVariationId(userId: String, experimentId: String) -> String? {
-        if let dic = whitelistUsers[userId] {
-            return dic[experimentId]
+    func getWhitelistedVariationId(userId: String, experimentId: String) -> String? {
+        if let dict = whitelistUsers.property?[userId] {
+            return dict[experimentId]
         }
 
         logger.d(.userHasNoForcedVariation(userId))
         return nil
     }
 
-    private func isValidVersion(version: String) -> Bool {
+    func isValidVersion(version: String) -> Bool {
         // old versions (< 4) of datafiles not supported
         return ["4"].contains(version)
     }

Tests/OptimizelyTests-MultiClients/ProjectConfigTests_MultiClients.swift

@@ -0,0 +1,49 @@
+//
+// Copyright 2021, Optimizely, Inc. and contributors 
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");  
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at   
+// 
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import XCTest
+
+class ProjectConfigTests_MultiClients: XCTestCase {
+    var config: ProjectConfig!
+    
+    override func setUpWithError() throws {
+        config = ProjectConfig()
+    }
+
+    func testConcurrentAccess() {
+        let numThreads = 10
+        let numEventsPerThread = 100
+        
+        let result = OTUtils.runConcurrent(count: numThreads) { thIdx in
+            for idx in 0..<numEventsPerThread {
+                let userId = String(idx)
+                let experimentId = String((thIdx * numEventsPerThread) + idx)
+                let variationId = experimentId
+
+                self.config.whitelistUser(userId: userId, experimentId: experimentId, variationId: variationId)
+                var result = self.config.getWhitelistedVariationId(userId: userId, experimentId: experimentId)
+                XCTAssertEqual(result, variationId)
+                
+                self.config.removeFromWhitelist(userId: userId, experimentId: experimentId)
+                result = self.config.getWhitelistedVariationId(userId: userId, experimentId: experimentId)
+                XCTAssertNil(result)
+            }
+        }
+        
+        XCTAssertTrue(result, "Concurrent tasks timed out")
+    }
+    
+}