d_date

@swift-5.6.3

@preconcurrency import Foundation import FoundationNetworking enum RequestData { @TaskLocal static var requestId: UUID! @TaskLocal static var startDate: Date! } struct Response: Encodable { let user: User let subscription: StripeSubscription } struct User: Encodable { var id: Int } func fetchUser() async throws -> User{ let requestId = RequestData.requestId! defer { print(requestId, "databaseQuery", "isCancelled", Task.isCancelled )} print(requestId, "Making database query") try await Task.sleep(nanoseconds: 500_000_000) print(requestId, "Finished database query") return User(id: 42) } struct StripeSubscription: Encodable { var id: Int} func fetchSubscription() async throws -> StripeSubscription { let requestId = RequestData.requestId! defer { print(requestId, "networkRequest", "isCancelled", Task.isCancelled )} print(requestId, "Making network request") try await Task.sleep(nanoseconds: 500_000_000) print(requestId, "Finished network request") return .init(id: 1729) } func response(for request: URLRequest) async throws -> Data { let requestId = RequestData.requestId! let start = RequestData.startDate! defer { print(requestId, "Request finished in", Date().timeIntervalSince(start)) } Task { print(RequestData.requestId!, "Track analytics") } async let user = fetchUser() async let subscription = fetchSubscription() let jsonData = try await JSONEncoder().encode( Response( user: user, subscription: subscription ) ) return jsonData } RequestData.$requestId.withValue(UUID()) { RequestData.$startDate.withValue(Date()) { let task = Task { _ = try await response(for: .init(url: .init(string: "https://www.pointfree.co")!)) } Thread.sleep(forTimeInterval: 0.1) } } Thread.sleep(forTimeInterval: 5)

(edited)

2C9A9B92-608A-4F07-A935-BB5C5A212108 Making database query 2C9A9B92-608A-4F07-A935-BB5C5A212108 Track analytics 2C9A9B92-608A-4F07-A935-BB5C5A212108 Making network request 2C9A9B92-608A-4F07-A935-BB5C5A212108 Finished network request 2C9A9B92-608A-4F07-A935-BB5C5A212108 Finished database query 2C9A9B92-608A-4F07-A935-BB5C5A212108 databaseQuery isCancelled false 2C9A9B92-608A-4F07-A935-BB5C5A212108 networkRequest isCancelled false 2C9A9B92-608A-4F07-A935-BB5C5A212108 Request finished in 0.5029729604721069

stderr:

<stdin>:58:9: warning: initialization of immutable value 'task' was never used; consider replacing with assignment to '_' or removing it let task = Task { ~~~~^~~~ _

(edited)