LambdaConfiguration.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftAWSLambdaRuntime open source project
//
// Copyright (c) 2017-2021 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 Dispatch
import Logging
import NIOCore

struct LambdaConfiguration: CustomStringConvertible {
    let general: General
    let lifecycle: Lifecycle
    let runtimeEngine: RuntimeEngine

    init() {
        self.init(general: .init(), lifecycle: .init(), runtimeEngine: .init())
    }

    init(general: General? = nil, lifecycle: Lifecycle? = nil, runtimeEngine: RuntimeEngine? = nil) {
        self.general = general ?? General()
        self.lifecycle = lifecycle ?? Lifecycle()
        self.runtimeEngine = runtimeEngine ?? RuntimeEngine()
    }

    struct General: CustomStringConvertible {
        let logLevel: Logger.Level

        init(logLevel: Logger.Level? = nil) {
            self.logLevel = logLevel ?? Lambda.env("LOG_LEVEL").flatMap(Logger.Level.init) ?? .info
        }

        var description: String {
            "\(General.self)(logLevel: \(self.logLevel))"
        }
    }

    struct Lifecycle: CustomStringConvertible {
        let id: String
        let maxTimes: Int
        let stopSignal: Signal

        init(id: String? = nil, maxTimes: Int? = nil, stopSignal: Signal? = nil) {
            self.id = id ?? "\(DispatchTime.now().uptimeNanoseconds)"
            self.maxTimes = maxTimes ?? Lambda.env("MAX_REQUESTS").flatMap(Int.init) ?? 0
            self.stopSignal = stopSignal ?? Lambda.env("STOP_SIGNAL").flatMap(Int32.init).flatMap(Signal.init) ?? Signal.TERM
            precondition(self.maxTimes >= 0, "maxTimes must be equal or larger than 0")
        }

        var description: String {
            "\(Lifecycle.self)(id: \(self.id), maxTimes: \(self.maxTimes), stopSignal: \(self.stopSignal))"
        }
    }

    struct RuntimeEngine: CustomStringConvertible {
        let ip: String
        let port: Int
        let requestTimeout: TimeAmount?

        init(address: String? = nil, keepAlive: Bool? = nil, requestTimeout: TimeAmount? = nil) {
            let ipPort = (address ?? Lambda.env("AWS_LAMBDA_RUNTIME_API"))?.split(separator: ":") ?? ["127.0.0.1", "7000"]
            guard ipPort.count == 2, let port = Int(ipPort[1]) else {
                preconditionFailure("invalid ip+port configuration \(ipPort)")
            }
            self.ip = String(ipPort[0])
            self.port = port
            self.requestTimeout = requestTimeout ?? Lambda.env("REQUEST_TIMEOUT").flatMap(Int64.init).flatMap { .milliseconds($0) }
        }

        var description: String {
            "\(RuntimeEngine.self)(ip: \(self.ip), port: \(self.port), requestTimeout: \(String(describing: self.requestTimeout))"
        }
    }

    var description: String {
        "\(Self.self)\n  \(self.general))\n  \(self.lifecycle)\n  \(self.runtimeEngine)"
    }
}