feat: Add AmplifyConfiguration file-based initializer (#707)

refs:#460

Co-authored-by: Michael Law <[email protected]>

Author: palpatim

Amplify.xcodeproj/project.pbxproj

@@ -415,6 +415,7 @@
 		FA6BC87F235F5DAE0001A882 /* APICategoryInterceptorBehavior.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA6BC87E235F5DAE0001A882 /* APICategoryInterceptorBehavior.swift */; };
 		FA76A2D12342B1A600B91ADB /* StorageCategory+HubPayloadEventName.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA76A2D02342B1A600B91ADB /* StorageCategory+HubPayloadEventName.swift */; };
 		FA76A2D32342B47100B91ADB /* HubPayloadEventName.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA76A2D22342B47100B91ADB /* HubPayloadEventName.swift */; };
+		FA87609324E45091004148C6 /* AmplifyConfigurationInitFromFileTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA87609024E44CCC004148C6 /* AmplifyConfigurationInitFromFileTests.swift */; };
 		FA8EE779238627040097E4F1 /* Model+ModelName.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA8EE778238627040097E4F1 /* Model+ModelName.swift */; };
 		FA8EE77D238627350097E4F1 /* Model+Subscript.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA8EE77C238627350097E4F1 /* Model+Subscript.swift */; };
 		FA8EE781238628490097E4F1 /* Persistable.swift in Sources */ = {isa = PBXBuildFile; fileRef = FA8EE780238628490097E4F1 /* Persistable.swift */; };
@@ -1205,6 +1206,7 @@
 		FA6BC87E235F5DAE0001A882 /* APICategoryInterceptorBehavior.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = APICategoryInterceptorBehavior.swift; sourceTree = "<group>"; };
 		FA76A2D02342B1A600B91ADB /* StorageCategory+HubPayloadEventName.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "StorageCategory+HubPayloadEventName.swift"; sourceTree = "<group>"; };
 		FA76A2D22342B47100B91ADB /* HubPayloadEventName.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = HubPayloadEventName.swift; sourceTree = "<group>"; };
+		FA87609024E44CCC004148C6 /* AmplifyConfigurationInitFromFileTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AmplifyConfigurationInitFromFileTests.swift; sourceTree = "<group>"; };
 		FA8EE772238621320097E4F1 /* AnyModelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AnyModelTests.swift; sourceTree = "<group>"; };
 		FA8EE776238626D60097E4F1 /* AnyModel+Codable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AnyModel+Codable.swift"; sourceTree = "<group>"; };
 		FA8EE778238627040097E4F1 /* Model+ModelName.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Model+ModelName.swift"; sourceTree = "<group>"; };
@@ -3028,9 +3030,10 @@
 		FACA35F32327FB14000E74F6 /* AmplifyFunctionalTests */ = {
 			isa = PBXGroup;
 			children = (
-				FA9D6C1D238DEEF900C7DD9F /* Hub */,
-				FACA35F42327FB14000E74F6 /* AmplifyConfigurationTests.swift */,
 				FACA35F62327FB14000E74F6 /* Info.plist */,
+				FA87609024E44CCC004148C6 /* AmplifyConfigurationInitFromFileTests.swift */,
+				FACA35F42327FB14000E74F6 /* AmplifyConfigurationTests.swift */,
+				FA9D6C1D238DEEF900C7DD9F /* Hub */,
 			);
 			path = AmplifyFunctionalTests;
 			sourceTree = "<group>";
@@ -4465,6 +4468,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				FA9D6C1E238DEF0E00C7DD9F /* DefaultHubPluginPerformanceTestHelpers.swift in Sources */,
+				FA87609324E45091004148C6 /* AmplifyConfigurationInitFromFileTests.swift in Sources */,
 				FA9D6C1F238DEF1100C7DD9F /* SerialDispatcherPerformanceTests.swift in Sources */,
 				FA9D6C1B238DEEEB00C7DD9F /* ConcurrentDispatcherPerformanceTests.swift in Sources */,
 				FACA35F52327FB14000E74F6 /* AmplifyConfigurationTests.swift in Sources */,

Amplify/Core/Configuration/AmplifyConfiguration.swift

@@ -61,6 +61,12 @@ public struct AmplifyConfiguration: Codable {
         self.predictions = predictions
         self.storage = storage
     }
+
+    /// Initialize `AmplifyConfiguration` by loading it from a URL representing the configuration file.
+    public init(configurationFile url: URL) throws {
+        self = try AmplifyConfiguration.loadAmplifyConfiguration(from: url)
+    }
+
 }
 
 // MARK: - Configure

Amplify/Core/Configuration/Internal/AmplifyConfigurationInitialization.swift

@@ -28,10 +28,6 @@ extension AmplifyConfiguration {
         self = try AmplifyConfiguration.loadAmplifyConfiguration(from: url)
     }
 
-    init(configurationFile url: URL) throws {
-        self = try AmplifyConfiguration.loadAmplifyConfiguration(from: url)
-    }
-
     static func loadAmplifyConfiguration(from url: URL) throws -> AmplifyConfiguration {
         let fileData: Data
         do {

AmplifyFunctionalTests/AmplifyConfigurationInitFromFileTests.swift

@@ -0,0 +1,37 @@
+//
+// Copyright 2018-2020 Amazon.com,
+// Inc. or its affiliates. All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import XCTest
+import Amplify
+
+/// Test the public AmplifyConfiguration initializer. Note that this means we must not import
+/// Amplify as `@testable`. That means we cannot `Amplify.reset()`, which means we can only have
+/// one test in this file. Further, this means we need to ensure that other tests do call
+/// `Amplify.reset()` in their static `setUp()` and `tearDown()` methods.
+class AmplifyConfigurationInitFromFileTests: XCTestCase {
+
+    func testInitFromFile() throws {
+        let configString = """
+        {
+            "UserAgent": "aws-amplify-cli/2.0",
+            "Version": "1.0"
+        }
+        """
+
+        let configData = configString.data(using: .utf8)!
+        let configURL = FileManager
+            .default
+            .temporaryDirectory
+            .appendingPathComponent("testconfig.json")
+        try configData.write(to: configURL)
+
+        var config: AmplifyConfiguration!
+        XCTAssertNoThrow(config = try AmplifyConfiguration(configurationFile: configURL))
+        XCTAssertNoThrow(try Amplify.configure(config))
+    }
+
+}

AmplifyFunctionalTests/AmplifyConfigurationTests.swift

@@ -12,6 +12,14 @@ import XCTest
 
 class AmplifyConfigurationTests: XCTestCase {
 
+    override static func setUp() {
+        Amplify.reset()
+    }
+
+    override static func tearDown() {
+        Amplify.reset()
+    }
+
     override func setUp() {
         Amplify.reset()
     }

AmplifyFunctionalTests/Hub/SerialDispatcherPerformanceTests.swift

@@ -12,6 +12,14 @@ class SerialDispatcherPerformanceTests: XCTestCase {
 
     let dispatcherTypeUnderTest = SerialDispatcher.self
 
+    override static func setUp() {
+        Amplify.reset()
+    }
+
+    override static func tearDown() {
+        Amplify.reset()
+    }
+
     override func setUp() {
         Amplify.reset()
         let config = AmplifyConfiguration()