Add a full working Serverless API example using APIGateway, Lambda, DynamoDB

Examples/LambdaFunctions/Package.swift

@@ -18,12 +18,20 @@ let package = Package(
         .executable(name: "APIGateway", targets: ["APIGateway"]),
         // fully featured example with domain specific business logic
         .executable(name: "CurrencyExchange", targets: ["CurrencyExchange"]),
+        // Full REST API Example using APIGateway, Lambda, DynamoDB
+        .executable(name: "ProductAPI", targets: ["ProductAPI"]),
     ],
     dependencies: [
         // this is the dependency on the swift-aws-lambda-runtime library
         // in real-world projects this would say
         // .package(url: "https://github.com/swift-server/swift-aws-lambda-runtime.git", from: "1.0.0")
         .package(name: "swift-aws-lambda-runtime", path: "../.."),
+
+        // The following packages are required by LambdaAPI
+        // AWS SDK Swift
+        .package(url: "https://github.com/soto-project/soto.git", from: "5.0.0-beta.2"),
+        // Logging
+        .package(url: "https://github.com/apple/swift-log.git", from: "1.0.0"),
     ],
     targets: [
         .target(name: "HelloWorld", dependencies: [
@@ -42,5 +50,12 @@ let package = Package(
         .target(name: "CurrencyExchange", dependencies: [
             .product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),
         ]),
+        .target(name: "ProductAPI", dependencies: [
+                .product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime"),
+                .product(name: "AWSLambdaEvents", package: "swift-aws-lambda-runtime"),
+                .product(name: "SotoDynamoDB", package: "soto"),
+                .product(name: "Logging", package: "swift-log"),
+            ]
+        )
     ]
 )

Examples/LambdaFunctions/Sources/ProductAPI/APIGateway+Extensions.swift

@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import AWSLambdaEvents
+import class Foundation.JSONEncoder
+import class Foundation.JSONDecoder
+
+extension APIGateway.V2.Request {
+
+    static private let decoder = JSONDecoder()
+
+    public func bodyObject<T: Codable>() throws -> T {
+        guard let body = self.body,
+            let dataBody = body.data(using: .utf8)
+            else {
+                throw APIError.invalidRequest
+        }
+        return try Self.decoder.decode(T.self, from: dataBody)
+    }
+}
+
+extension APIGateway.V2.Response {
+
+    private static let encoder = JSONEncoder()
+
+    public static let defaultHeaders = [
+        "Content-Type": "application/json",
+        //Security warning: XSS are enabled
+        "Access-Control-Allow-Origin": "*",
+        "Access-Control-Allow-Methods": "OPTIONS,GET,POST,PUT,DELETE",
+        "Access-Control-Allow-Credentials": "true",
+    ]
+
+    public init(with error: Error, statusCode: AWSLambdaEvents.HTTPResponseStatus) {
+        self.init(
+            statusCode: statusCode,
+            headers: APIGateway.V2.Response.defaultHeaders,
+            multiValueHeaders: nil,
+            body: "{\"message\":\"\(String(describing: error))\"}",
+            isBase64Encoded: false
+        )
+    }
+
+    public init<Out: Encodable>(with object: Out, statusCode: AWSLambdaEvents.HTTPResponseStatus) {
+        var body: String = "{}"
+        if let data = try? Self.encoder.encode(object) {
+            body = String(data: data, encoding: .utf8) ?? body
+        }
+        self.init(
+            statusCode: statusCode,
+            headers: APIGateway.V2.Response.defaultHeaders,
+            multiValueHeaders: nil,
+            body: body,
+            isBase64Encoded: false
+        )
+    }
+}

Examples/LambdaFunctions/Sources/ProductAPI/Product.swift

@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+
+public struct Product: Codable {
+    public let sku: String
+    public let name: String
+    public let description: String
+    public var createdAt: String?
+    public var updatedAt: String?
+
+    public struct Field {
+        static let sku = "sku"
+        static let name = "name"
+        static let description = "description"
+        static let createdAt = "createdAt"
+        static let updatedAt = "updatedAt"
+    }
+}

Examples/LambdaFunctions/Sources/ProductAPI/ProductLambda.swift

@@ -0,0 +1,103 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import SotoDynamoDB
+import AWSLambdaEvents
+import AWSLambdaRuntime
+import AsyncHTTPClient
+import Logging
+import NIO
+
+enum Operation: String {
+    case create
+    case read
+    case update
+    case delete
+    case list
+}
+
+struct EmptyResponse: Codable {}
+
+struct ProductLambda: LambdaHandler {
+
+    typealias In = APIGateway.V2.Request
+    typealias Out = APIGateway.V2.Response
+
+    let dbTimeout: Int64 = 30
+    let region: Region
+    let db: SotoDynamoDB.DynamoDB
+    let service: ProductService
+    let tableName: String
+    let operation: Operation
+    var httpClient: HTTPClient
+
+    static func currentRegion() -> Region {
+        if let awsRegion = Lambda.env("AWS_REGION") {
+            let value = Region(rawValue: awsRegion)
+            return value
+        } else {
+            return .useast1
+        }
+    }
+
+    static func tableName() throws -> String {
+        guard let tableName = Lambda.env("PRODUCTS_TABLE_NAME") else {
+            throw APIError.tableNameNotFound
+        }
+        return tableName
+    }
+
+    init(context: Lambda.InitializationContext) throws {
+
+        guard let handler = Lambda.env("_HANDLER"),
+            let operation = Operation(rawValue: handler) else {
+                throw APIError.invalidHandler
+        }
+        self.operation = operation
+        self.region = Self.currentRegion()
+
+        let lambdaRuntimeTimeout: TimeAmount = .seconds(dbTimeout)
+        let timeout = HTTPClient.Configuration.Timeout(
+            connect: lambdaRuntimeTimeout,
+            read: lambdaRuntimeTimeout
+        )
+
+        let configuration = HTTPClient.Configuration(timeout: timeout)
+        self.httpClient = HTTPClient(
+            eventLoopGroupProvider: .shared(context.eventLoop),
+            configuration: configuration
+        )
+
+        let awsClient = AWSClient(httpClientProvider: .shared(self.httpClient))
+
+        self.db = SotoDynamoDB.DynamoDB(client: awsClient, region: region)
+        self.tableName = try Self.tableName()
+
+        self.service = ProductService(
+            db: db,
+            tableName: tableName
+        )
+    }
+
+    func handle(
+        context: Lambda.Context, event: APIGateway.V2.Request,
+        callback: @escaping (Result<APIGateway.V2.Response, Error>) -> Void
+    ) {
+        let _ = ProductLambdaHandler(service: service, operation: operation)
+            .handle(context: context, event: event)
+            .always { (result) in
+                callback(result)
+        }
+    }
+}

Examples/LambdaFunctions/Sources/ProductAPI/ProductLambdaHandler.swift

@@ -0,0 +1,109 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import AWSLambdaEvents
+import AWSLambdaRuntime
+import Logging
+import NIO
+
+struct ProductLambdaHandler: EventLoopLambdaHandler {
+
+    typealias In = APIGateway.V2.Request
+    typealias Out = APIGateway.V2.Response
+
+    let service: ProductService
+    let operation: Operation
+
+    func handle(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+
+        switch self.operation {
+        case .create:
+            return createLambdaHandler(context: context, event: event)
+        case .read:
+            return readLambdaHandler(context: context, event: event)
+        case .update:
+            return updateLambdaHandler(context: context, event: event)
+        case .delete:
+            return deleteUpdateLambdaHandler(context: context, event: event)
+        case .list:
+            return listUpdateLambdaHandler(context: context, event: event)
+        }
+    }
+
+    func createLambdaHandler(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+        guard let product: Product = try? event.bodyObject() else {
+            let error = APIError.invalidRequest
+            return context.eventLoop.makeFailedFuture(error)
+        }
+        return service.createItem(product: product)
+            .map { result -> (APIGateway.V2.Response) in
+                return APIGateway.V2.Response(with: result, statusCode: .created)
+        }.flatMapError { (error) -> EventLoopFuture<APIGateway.V2.Response> in
+            let value = APIGateway.V2.Response(with: error, statusCode: .forbidden)
+            return context.eventLoop.makeSucceededFuture(value)
+        }
+    }
+
+    func readLambdaHandler(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+        guard let sku = event.pathParameters?["sku"] else {
+            let error = APIError.invalidRequest
+            return context.eventLoop.makeFailedFuture(error)
+        }
+        return service.readItem(key: sku)
+            .flatMapThrowing { result -> APIGateway.V2.Response in
+                return APIGateway.V2.Response(with: result, statusCode: .ok)
+        }.flatMapError { (error) -> EventLoopFuture<APIGateway.V2.Response> in
+            let value = APIGateway.V2.Response(with: error, statusCode: .notFound)
+            return context.eventLoop.makeSucceededFuture(value)
+        }
+    }
+
+    func updateLambdaHandler(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+        guard let product: Product = try? event.bodyObject() else {
+            let error = APIError.invalidRequest
+            return context.eventLoop.makeFailedFuture(error)
+        }
+        return service.updateItem(product: product)
+            .map { result -> (APIGateway.V2.Response) in
+                return APIGateway.V2.Response(with: result, statusCode: .ok)
+        }.flatMapError { (error) -> EventLoopFuture<APIGateway.V2.Response> in
+            let value = APIGateway.V2.Response(with: error, statusCode: .notFound)
+            return context.eventLoop.makeSucceededFuture(value)
+        }
+    }
+
+    func deleteUpdateLambdaHandler(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+        guard let sku = event.pathParameters?["sku"] else {
+            let error = APIError.invalidRequest
+            return context.eventLoop.makeFailedFuture(error)
+        }
+        return service.deleteItem(key: sku)
+            .map { _ -> (APIGateway.V2.Response) in
+                return APIGateway.V2.Response(with: EmptyResponse(), statusCode: .ok)
+        }.flatMapError { (error) -> EventLoopFuture<APIGateway.V2.Response> in
+            let value = APIGateway.V2.Response(with: error, statusCode: .notFound)
+            return context.eventLoop.makeSucceededFuture(value)
+        }
+    }
+
+    func listUpdateLambdaHandler(context: Lambda.Context, event: APIGateway.V2.Request) -> EventLoopFuture<APIGateway.V2.Response> {
+        return service.listItems()
+            .flatMapThrowing { result -> APIGateway.V2.Response in
+                return APIGateway.V2.Response(with: result, statusCode: .ok)
+        }.flatMapError { (error) -> EventLoopFuture<APIGateway.V2.Response> in
+            let value = APIGateway.V2.Response(with: error, statusCode: .forbidden)
+            return context.eventLoop.makeSucceededFuture(value)
+        }
+    }
+}