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add debug functionality to test with mock server
motivation: allow end to end testing locally changes: * add a Lambda+LocalServer which exposes Lambda.withLocalServer available only in DEBUG mode * local server can recieve POST requests with payloads on a configurable endpoint and and send them to the Lambda * add a "noContent" mode to Lambda runtime to allow polling
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7 files changed

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-20
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7 files changed

+267
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lines changed

‎Package.swift

+4-12
Original file line numberDiff line numberDiff line change
@@ -47,20 +47,12 @@ let package = Package(
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.byName(name: "AWSLambdaRuntime"),
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.product(name: "NIO", package: "swift-nio"),
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]),
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.testTarget(name: "AWSLambdaTestingTests", dependencies: [
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.byName(name: "AWSLambdaTesting"),
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.byName(name: "AWSLambdaRuntime"),
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]),
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// samples
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.target(name: "StringSample", dependencies: [
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.byName(name: "AWSLambdaRuntime"),
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]),
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.target(name: "CodableSample", dependencies: [
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.byName(name: "AWSLambdaRuntime"),
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]),
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// perf tests
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.testTarget(name: "AWSLambdaTestingTests", dependencies: ["AWSLambdaTesting"]),
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// for perf testing
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.target(name: "MockServer", dependencies: [
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.product(name: "NIOHTTP1", package: "swift-nio"),
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]),
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.target(name: "StringSample", dependencies: ["AWSLambdaRuntime"]),
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.target(name: "CodableSample", dependencies: ["AWSLambdaRuntime"]),
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]
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)

‎Sources/AWSLambdaRuntime/Lambda+LocalServer.swift

+222
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,222 @@
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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the SwiftAWSLambdaRuntime open source project
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//
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// Copyright (c) 2020 Apple Inc. and the SwiftAWSLambdaRuntime project authors
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// Licensed under Apache License v2.0
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//
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// See LICENSE.txt for license information
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// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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//===----------------------------------------------------------------------===//
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import Dispatch
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import Logging
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import NIO
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import NIOConcurrencyHelpers
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import NIOHTTP1
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// This functionality is designed for local testing hence beind a #if DEBUG flag.
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// For example:
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//
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// try Lambda.withLocalServer {
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// Lambda.run { (context: Lambda.Context, payload: String, callback: @escaping (Result<String, Error>) -> Void) in
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// callback(.success("Hello, \(payload)!"))
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// }
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// }
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#if DEBUG
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extension Lambda {
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/// Execute code in the context of a mock Lambda server.
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///
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/// - parameters:
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/// - invocationEndpoint: The endpoint to post payloads to.
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/// - body: Code to run within the context of the mock server. Typically this would be a Lambda.run function call.
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///
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/// - note: This API is designed stricly for local testing and is behind a DEBUG flag
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public static func withLocalServer(invocationEndpoint: String? = nil, _ body: @escaping () -> Void) throws {
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let server = LocalLambda.Server(invocationEndpoint: invocationEndpoint)
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try server.start().wait()
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defer { try! server.stop() } // FIXME:
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body()
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}
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}
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// MARK: - Local Mock Server
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private enum LocalLambda {
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struct Server {
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private let logger: Logger
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private let group: EventLoopGroup
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private let host: String
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private let port: Int
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private let invocationEndpoint: String
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public init(invocationEndpoint: String?) {
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let configuration = Lambda.Configuration()
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var logger = Logger(label: "LocalLambdaServer")
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logger.logLevel = configuration.general.logLevel
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self.logger = logger
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self.group = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
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self.host = configuration.runtimeEngine.ip
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self.port = configuration.runtimeEngine.port
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self.invocationEndpoint = invocationEndpoint ?? "/invoke"
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}
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func start() -> EventLoopFuture<Void> {
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let bootstrap = ServerBootstrap(group: group)
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.serverChannelOption(ChannelOptions.socket(SocketOptionLevel(SOL_SOCKET), SO_REUSEADDR), value: 1)
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.childChannelInitializer { channel in
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channel.pipeline.configureHTTPServerPipeline(withErrorHandling: true).flatMap { _ in
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channel.pipeline.addHandler(HTTPHandler(logger: self.logger, invocationEndpoint: self.invocationEndpoint))
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}
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}
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return bootstrap.bind(host: self.host, port: self.port).flatMap { channel -> EventLoopFuture<Void> in
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guard channel.localAddress != nil else {
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return channel.eventLoop.makeFailedFuture(ServerError.cantBind)
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}
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self.logger.info("LocalLambdaServer started and listening on \(self.host):\(self.port), receiving payloads on \(self.invocationEndpoint)")
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return channel.eventLoop.makeSucceededFuture(())
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}
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}
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func stop() throws {
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try self.group.syncShutdownGracefully()
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}
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}
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final class HTTPHandler: ChannelInboundHandler {
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public typealias InboundIn = HTTPServerRequestPart
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public typealias OutboundOut = HTTPServerResponsePart
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private static let queueLock = Lock()
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private static var queue = [String: Pending]()
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private var processing = CircularBuffer<(head: HTTPRequestHead, body: ByteBuffer?)>()
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private let logger: Logger
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private let invocationEndpoint: String
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init(logger: Logger, invocationEndpoint: String) {
103+
self.logger = logger
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self.invocationEndpoint = invocationEndpoint
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}
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func channelRead(context: ChannelHandlerContext, data: NIOAny) {
108+
let requestPart = unwrapInboundIn(data)
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switch requestPart {
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case .head(let head):
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self.processing.append((head: head, body: nil))
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case .body(var buffer):
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var request = self.processing.removeFirst()
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if request.body == nil {
116+
request.body = buffer
117+
} else {
118+
request.body!.writeBuffer(&buffer)
119+
}
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self.processing.prepend(request)
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case .end:
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let request = self.processing.removeFirst()
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self.processRequest(context: context, request: request)
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}
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}
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func processRequest(context: ChannelHandlerContext, request: (head: HTTPRequestHead, body: ByteBuffer?)) {
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if request.head.uri.hasSuffix(self.invocationEndpoint) {
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if let work = request.body {
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let requestId = "\(DispatchTime.now().uptimeNanoseconds)" // FIXME:
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let promise = context.eventLoop.makePromise(of: Response.self)
132+
promise.futureResult.whenComplete { result in
133+
switch result {
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case .success(let response):
135+
self.writeResponse(context: context, response: response)
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case .failure:
137+
self.writeResponse(context: context, response: .init(status: .internalServerError))
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}
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}
140+
Self.queueLock.withLock {
141+
Self.queue[requestId] = Pending(requestId: requestId, request: work, responsePromise: promise)
142+
}
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}
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} else if request.head.uri.hasSuffix("/next") {
145+
switch (Self.queueLock.withLock { Self.queue.popFirst() }) {
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case .none:
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self.writeResponse(context: context, response: .init(status: .noContent))
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case .some(let pending):
149+
var response = Response()
150+
response.body = pending.value.request
151+
// required headers
152+
response.headers = [
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(AmazonHeaders.requestID, pending.key),
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(AmazonHeaders.invokedFunctionARN, "arn:aws:lambda:us-east-1:\(Int16.random(in: Int16.min ... Int16.max)):function:custom-runtime"),
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(AmazonHeaders.traceID, "Root=\(Int16.random(in: Int16.min ... Int16.max));Parent=\(Int16.random(in: Int16.min ... Int16.max));Sampled=1"),
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(AmazonHeaders.deadline, "\(DispatchWallTime.distantFuture.millisSinceEpoch)"),
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]
158+
Self.queueLock.withLock {
159+
Self.queue[pending.key] = pending.value
160+
}
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self.writeResponse(context: context, response: response)
162+
}
163+
164+
} else if request.head.uri.hasSuffix("/response") {
165+
let parts = request.head.uri.split(separator: "/")
166+
guard let requestId = parts.count > 2 ? String(parts[parts.count - 2]) : nil else {
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return self.writeResponse(context: context, response: .init(status: .badRequest))
168+
}
169+
switch (Self.queueLock.withLock { Self.queue[requestId] }) {
170+
case .none:
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self.writeResponse(context: context, response: .init(status: .badRequest))
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case .some(let pending):
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pending.responsePromise.succeed(.init(status: .ok, body: request.body))
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self.writeResponse(context: context, response: .init(status: .accepted))
175+
Self.queueLock.withLock { Self.queue[requestId] = nil }
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}
177+
} else {
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self.writeResponse(context: context, response: .init(status: .notFound))
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}
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}
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func writeResponse(context: ChannelHandlerContext, response: Response) {
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var headers = HTTPHeaders(response.headers ?? [])
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headers.add(name: "content-length", value: "\(response.body?.readableBytes ?? 0)")
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let head = HTTPResponseHead(version: HTTPVersion(major: 1, minor: 1), status: response.status, headers: headers)
186+
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context.write(wrapOutboundOut(.head(head))).whenFailure { error in
188+
self.logger.error("\(self) write error \(error)")
189+
}
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if let buffer = response.body {
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context.write(wrapOutboundOut(.body(.byteBuffer(buffer)))).whenFailure { error in
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self.logger.error("\(self) write error \(error)")
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}
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}
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context.writeAndFlush(wrapOutboundOut(.end(nil))).whenComplete { result in
198+
if case .failure(let error) = result {
199+
self.logger.error("\(self) write error \(error)")
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}
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}
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}
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struct Response {
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var status: HTTPResponseStatus = .ok
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var headers: [(String, String)]?
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var body: ByteBuffer?
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}
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struct Pending {
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let requestId: String
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let request: ByteBuffer
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let responsePromise: EventLoopPromise<Response>
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}
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}
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enum ServerError: Error {
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case notReady
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case cantBind
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}
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}
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#endif

‎Sources/AWSLambdaRuntimeCore/LambdaContext.swift

+5-1
Original file line numberDiff line numberDiff line change
@@ -19,7 +19,7 @@ import NIO
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extension Lambda {
2020
/// Lambda runtime context.
2121
/// The Lambda runtime generates and passes the `Context` to the Lambda handler as an argument.
22-
public final class Context {
22+
public final class Context: CustomDebugStringConvertible {
2323
/// The request ID, which identifies the request that triggered the function invocation.
2424
public let requestId: String
2525

@@ -85,5 +85,9 @@ extension Lambda {
8585
let remaining = deadline - now
8686
return .milliseconds(remaining)
8787
}
88+
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public var debugDescription: String {
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"\(Self.self)(requestId: \(self.requestId), traceId: \(self.traceId), invokedFunctionArn: \(self.invokedFunctionArn), cognitoIdentity: \(self.cognitoIdentity ?? "nil"), clientContext: \(self.clientContext ?? "nil"), deadline: \(self.deadline))"
91+
}
8892
}
8993
}

‎Sources/AWSLambdaRuntimeCore/LambdaRunner.swift

+13-4
Original file line numberDiff line numberDiff line change
@@ -45,9 +45,12 @@ extension Lambda {
4545

4646
func run(logger: Logger, handler: Handler) -> EventLoopFuture<Void> {
4747
logger.debug("lambda invocation sequence starting")
48-
// 1. request invocation from lambda runtime engine
49-
return self.runtimeClient.getNextInvocation(logger: logger).peekError { error in
50-
logger.error("could not fetch invocation from lambda runtime engine: \(error)")
48+
// 1. request work from lambda runtime engine
49+
return self.runtimeClient.requestWork(logger: logger).peekError { error -> Void in
50+
if case RuntimeError.badStatusCode(.noContent) = error {
51+
return
52+
}
53+
logger.error("could not fetch work from lambda runtime engine: \(error)")
5154
}.flatMap { invocation, payload in
5255
// 2. send invocation to handler
5356
let context = Context(logger: logger, eventLoop: self.eventLoop, invocation: invocation)
@@ -64,7 +67,13 @@ extension Lambda {
6467
self.runtimeClient.reportResults(logger: logger, invocation: invocation, result: result).peekError { error in
6568
logger.error("could not report results to lambda runtime engine: \(error)")
6669
}
67-
}.always { result in
70+
}.flatMapErrorThrowing { error in
71+
if case RuntimeError.badStatusCode(.noContent) = error {
72+
return ()
73+
}
74+
throw error
75+
}
76+
.always { result in
6877
// we are done!
6978
logger.log(level: result.successful ? .debug : .warning, "lambda invocation sequence completed \(result.successful ? "successfully" : "with failure")")
7079
}

‎Sources/AWSLambdaTesting/Lambda+Testing.swift

+19-1
Original file line numberDiff line numberDiff line change
@@ -12,9 +12,27 @@
1212
//
1313
//===----------------------------------------------------------------------===//
1414

15-
// this is designed to only work for testing
15+
// This functionality is designed to help with Lambda unit testing with XCTest
1616
// #if filter required for release builds which do not support @testable import
1717
// @testable is used to access of internal functions
18+
// For exmaple:
19+
//
20+
// func test() {
21+
// struct MyLambda: EventLoopLambdaHandler {
22+
// typealias In = String
23+
// typealias Out = String
24+
//
25+
// func handle(context: Lambda.Context, payload: String) -> EventLoopFuture<String> {
26+
// return context.eventLoop.makeSucceededFuture("echo" + payload)
27+
// }
28+
// }
29+
//
30+
// let input = UUID().uuidString
31+
// var result: String?
32+
// XCTAssertNoThrow(result = try Lambda.test(MyLambda(), with: input))
33+
// XCTAssertEqual(result, "echo" + input)
34+
// }
35+
1836
#if DEBUG
1937
@testable import AWSLambdaRuntime
2038
@testable import AWSLambdaRuntimeCore

‎Sources/StringSample/main.swift

+3-1
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,9 @@ struct Handler: EventLoopLambdaHandler {
2626
}
2727
}
2828

29-
Lambda.run(Handler())
29+
try Lambda.withLocalServer {
30+
Lambda.run(Handler())
31+
}
3032

3133
// MARK: - this can also be expressed as a closure:
3234

‎docker/docker-compose.1804.53.yaml

+1-1
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@ services:
66
image: swift-aws-lambda:18.04-5.3
77
build:
88
args:
9-
base_image: "swiftlang/swift:nightly-bionic"
9+
base_image: "swiftlang/swift:nightly-5.3-bionic"
1010

1111
test:
1212
image: swift-aws-lambda:18.04-5.3

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