feat(datastore): StartSync with Auth (#471)

* feat(datastore): RemoteSyncEngine handles authentication state

* Add Integration test target

* Add integration test set up

* Move sync requirement to SyncEngine

* add check for listeners since each DataStore call will register a new listener

* update Auth plugin name

* Add clearCompleted event with integ test passing

* remove auth state listeners

* SyncQuery propagate error to error handler

* Coode clean up, remove clearCompleted hub event, Amplify core changes

* change hasAuth to hasAuthenticationRules

* PR feedback

* readme update

* fix unit test

Author: lawmicha

Amplify/Categories/Auth/AuthCategoryDeviceBehavior.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public protocol AuthCategoryDeviceBehavior {
+public protocol AuthCategoryDeviceBehavior: class {
 
     /// Fetch devices assigned to the current device
     /// - Parameters:

Amplify/Categories/Auth/AuthCategoryUserBehavior.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public protocol AuthCategoryUserBehavior {
+public protocol AuthCategoryUserBehavior: class {
 
     /// Returns the currently logged in user.
     ///

Amplify/Categories/DataStore/Model/Schema/ModelSchema+Attributes.swift

@@ -16,4 +16,7 @@ public extension ModelSchema {
         attributes.contains(.isSystem)
     }
 
+    var hasAuthenticationRules: Bool {
+        return !authRules.isEmpty
+    }
 }

AmplifyPlugins/API/AWSAPICategoryPluginIntegrationTests/GraphQL/GraphQLWithUserPoolIntegrationTests/AuthDirective/GraphQLAuthDirectiveIntegrationTests+Auth.swift

@@ -8,7 +8,6 @@
 import XCTest
 import AWSPluginsCore
 import AWSAPICategoryPlugin
-import AWSMobileClient
 
 @testable import Amplify
 @testable import AWSAPICategoryPluginTestCommon

AmplifyPlugins/API/AWSAPICategoryPluginIntegrationTests/GraphQL/GraphQLWithUserPoolIntegrationTests/AuthDirective/GraphQLAuthDirectiveIntegrationTests+Support.swift

@@ -8,7 +8,6 @@
 import XCTest
 import AWSPluginsCore
 import AWSAPICategoryPlugin
-import AWSMobileClient
 import AmplifyPlugins
 
 @testable import Amplify

AmplifyPlugins/API/AWSAPICategoryPluginIntegrationTests/GraphQL/GraphQLWithUserPoolIntegrationTests/AuthDirective/GraphQLAuthDirectiveIntegrationTests.swift

@@ -9,7 +9,6 @@ import XCTest
 import AWSPluginsCore
 import AWSAPICategoryPlugin
 import AmplifyPlugins
-import AWSMobileClient
 
 @testable import Amplify
 @testable import AWSAPICategoryPluginTestCommon

AmplifyPlugins/DataStore/AWSDataStoreCategoryPlugin/AWSDataStorePlugin.swift

@@ -24,6 +24,9 @@ final public class AWSDataStorePlugin: DataStoreCategoryPlugin {
     let dataStoreConfiguration: DataStoreConfiguration
 
     let validAPIPluginKey: String
+
+    let validAuthPluginKey: String
+
     /// The local storage provider. Resolved during configuration phase
     var storageEngine: StorageEngineBehavior!
 
@@ -48,6 +51,7 @@ final public class AWSDataStorePlugin: DataStoreCategoryPlugin {
         self.dataStoreConfiguration = dataStoreConfiguration
         self.isSyncEnabled = false
         self.validAPIPluginKey =  "awsAPIPlugin"
+        self.validAuthPluginKey = "awsCognitoAuthPlugin"
         if #available(iOS 13.0, *) {
             self.dataStorePublisher = DataStorePublisher()
         } else {
@@ -60,13 +64,15 @@ final public class AWSDataStorePlugin: DataStoreCategoryPlugin {
          configuration dataStoreConfiguration: DataStoreConfiguration = .default,
          storageEngine: StorageEngineBehavior,
          dataStorePublisher: DataStoreSubscribeBehavior,
-         validAPIPluginKey: String) {
+         validAPIPluginKey: String,
+         validAuthPluginKey: String) {
         self.modelRegistration = modelRegistration
         self.dataStoreConfiguration = dataStoreConfiguration
         self.isSyncEnabled = false
         self.storageEngine = storageEngine
         self.dataStorePublisher = dataStorePublisher
         self.validAPIPluginKey = validAPIPluginKey
+        self.validAuthPluginKey = validAuthPluginKey
     }
 
     /// By the time this method gets called, DataStore will already have invoked
@@ -82,27 +88,13 @@ final public class AWSDataStorePlugin: DataStoreCategoryPlugin {
         let filter = HubFilters.forEventName(HubPayload.EventName.Amplify.configured)
         var token: UnsubscribeToken?
         token = Amplify.Hub.listen(to: .dataStore, isIncluded: filter) { _ in
-            if self.hasValidAPIPlugin() {
-                self.storageEngine.startSync()
-            } else {
-                self.log.info("Unable to find suitable plugin for syncEngine.  syncEngine will not be started")
-            }
-
+            self.storageEngine.startSync()
             if let token = token {
                 Amplify.Hub.removeListener(token)
             }
         }
     }
 
-    func hasValidAPIPlugin() -> Bool {
-        do {
-            _ = try Amplify.API.getPlugin(for: validAPIPluginKey)
-            return true
-        } catch {
-            return false
-        }
-    }
-
     func reinitStorageEngineIfNeeded() {
         if storageEngine != nil {
             return
@@ -124,7 +116,10 @@ final public class AWSDataStorePlugin: DataStoreCategoryPlugin {
             return
         }
 
-        storageEngine = try StorageEngine(isSyncEnabled: isSyncEnabled, dataStoreConfiguration: dataStoreConfiguration)
+        storageEngine = try StorageEngine(isSyncEnabled: isSyncEnabled,
+                                          dataStoreConfiguration: dataStoreConfiguration,
+                                          validAPIPluginKey: validAPIPluginKey,
+                                          validAuthPluginKey: validAuthPluginKey)
         if #available(iOS 13.0, *) {
             setupStorageSink()
         }

AmplifyPlugins/DataStore/AWSDataStoreCategoryPlugin/Storage/StorageEngine+SyncRequirement.swift

@@ -0,0 +1,59 @@
+//
+// Copyright 2018-2020 Amazon.com,
+// Inc. or its affiliates. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Amplify
+import Combine
+import Foundation
+import AWSPluginsCore
+
+extension StorageEngine {
+
+    func startSync() {
+        guard let api = tryGetAPIPlugin() else {
+            log.info("Unable to find suitable API plugin for syncEngine. syncEngine will not be started")
+            return
+        }
+
+        let authPluginRequired = requiresAuthPlugin()
+
+        guard authPluginRequired else {
+            syncEngine?.start(api: api, auth: nil)
+            return
+        }
+
+        guard let auth = tryGetAuthPlugin() else {
+            log.warn("Unable to find suitable Auth plugin for syncEngine. Models require auth")
+            return
+        }
+
+        syncEngine?.start(api: api, auth: auth)
+    }
+
+    private func tryGetAPIPlugin() -> APICategoryGraphQLBehavior? {
+        do {
+            return try Amplify.API.getPlugin(for: validAPIPluginKey)
+        } catch {
+            return nil
+        }
+    }
+
+    private func tryGetAuthPlugin() -> AuthCategoryBehavior? {
+        do {
+            return try Amplify.Auth.getPlugin(for: validAuthPluginKey)
+        } catch {
+            return nil
+        }
+    }
+
+    private func requiresAuthPlugin() -> Bool {
+        let containsAuthEnabledSyncableModels = ModelRegistry.models.contains {
+            $0.schema.isSyncable && $0.schema.hasAuthenticationRules
+        }
+
+        return containsAuthEnabledSyncableModels
+    }
+}

AmplifyPlugins/DataStore/AWSDataStoreCategoryPlugin/Storage/StorageEngine.swift

@@ -14,8 +14,10 @@ final class StorageEngine: StorageEngineBehavior {
     // TODO: Make this private once we get a mutation flow that passes the type of mutation as needed
     let storageAdapter: StorageEngineAdapter
     private let dataStoreConfiguration: DataStoreConfiguration
-    private var syncEngine: RemoteSyncEngineBehavior?
-    private weak var api: APICategoryGraphQLBehavior?
+    var syncEngine: RemoteSyncEngineBehavior?
+    let validAPIPluginKey: String
+    let validAuthPluginKey: String
+    var signInListener: UnsubscribeToken?
 
     var iSyncEngineSink: Any?
     @available(iOS 13.0, *)
@@ -63,13 +65,20 @@ final class StorageEngine: StorageEngineBehavior {
     // storageAdapter must have already been set up with system models
     init(storageAdapter: StorageEngineAdapter,
          dataStoreConfiguration: DataStoreConfiguration,
-         syncEngine: RemoteSyncEngineBehavior?) {
+         syncEngine: RemoteSyncEngineBehavior?,
+         validAPIPluginKey: String,
+         validAuthPluginKey: String) {
         self.storageAdapter = storageAdapter
         self.dataStoreConfiguration = dataStoreConfiguration
         self.syncEngine = syncEngine
+        self.validAPIPluginKey = validAPIPluginKey
+        self.validAuthPluginKey = validAuthPluginKey
     }
 
-    convenience init(isSyncEnabled: Bool, dataStoreConfiguration: DataStoreConfiguration) throws {
+    convenience init(isSyncEnabled: Bool,
+                     dataStoreConfiguration: DataStoreConfiguration,
+                     validAPIPluginKey: String = "awsAPIPlugin",
+                     validAuthPluginKey: String = "awsCognitoAuthPlugin") throws {
         let key = kCFBundleNameKey as String
         let databaseName = Bundle.main.object(forInfoDictionaryKey: key) as? String
         let storageAdapter = try SQLiteStorageEngineAdapter(databaseName: databaseName ?? "app")
@@ -80,14 +89,18 @@ final class StorageEngine: StorageEngineBehavior {
                                                                    dataStoreConfiguration: dataStoreConfiguration) : nil
             self.init(storageAdapter: storageAdapter,
                       dataStoreConfiguration: dataStoreConfiguration,
-                      syncEngine: syncEngine)
+                      syncEngine: syncEngine,
+                      validAPIPluginKey: validAPIPluginKey,
+                      validAuthPluginKey: validAuthPluginKey)
             self.storageEnginePublisher = PassthroughSubject<StorageEngineEvent, DataStoreError>()
             sinkEngineSink = syncEngine?.publisher.sink(receiveCompletion: onReceiveCompletion(receiveCompletion:),
                                                         receiveValue: onReceive(receiveValue:))
         } else {
             self.init(storageAdapter: storageAdapter,
                       dataStoreConfiguration: dataStoreConfiguration,
-                      syncEngine: nil)
+                      syncEngine: nil,
+                      validAPIPluginKey: validAPIPluginKey,
+                      validAuthPluginKey: validAuthPluginKey)
         }
     }
 
@@ -319,10 +332,6 @@ final class StorageEngine: StorageEngineBehavior {
                                     completion: completion)
     }
 
-    func startSync() {
-        syncEngine?.start(api: Amplify.API)
-    }
-
     func clear(completion: @escaping DataStoreCallback<Void>) {
         if let syncEngine = syncEngine {
             syncEngine.stop(completion: { _ in

AmplifyPlugins/DataStore/AWSDataStoreCategoryPlugin/Storage/StorageEngineBehavior.swift

@@ -19,7 +19,7 @@ protocol StorageEngineBehavior: class, ModelStorageBehavior {
     @available(iOS 13.0, *)
     var publisher: AnyPublisher<StorageEngineEvent, DataStoreError> { get }
 
-    /// Tells the StorageEngine to begin syncing, if sync is enabled
+    /// start remote sync, based on if sync is enabled and/or authentication is required
     func startSync()
 
     func clear(completion: @escaping DataStoreCallback<Void>)