サーバエコシステムでのSwiftの詳細

3:23 - EventService Package.swift

// swift-tools-version:5.9
import PackageDescription

let package = Package(
  name: "EventService",
  platforms: [.macOS(.v14)],
  dependencies: [
    .package(
      url: "https://github.com/apple/swift-openapi-generator",
      from: "1.2.1"
    ),
    .package(
      url: "https://github.com/apple/swift-openapi-runtime",
      from: "1.4.0"
    ),
    .package(
      url: "https://github.com/vapor/vapor",
      from: "4.99.2"
    ),
    .package(
      url: "https://github.com/swift-server/swift-openapi-vapor",
      from: "1.0.1"
    ),
  ],
  targets: [
    .target(
      name: "EventAPI",
      dependencies: [
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
      ],
      plugins: [
        .plugin(
          name: "OpenAPIGenerator",
          package: "swift-openapi-generator"
        )
      ]
    ),
    .executableTarget(
      name: "EventService",
      dependencies: [
        "EventAPI",
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
        .product(
          name: "OpenAPIVapor",
          package: "swift-openapi-vapor"
        ),
        .product(
          name: "Vapor",
          package: "vapor"
        ),
      ]
    ),
  ]
)

4:05 - EventService openapi.yaml

openapi: "3.1.0"
info:
  title: "EventService"
  version: "1.0.0"
servers:
  - url: "https://localhost:8080/api"
    description: "Example service deployment."
paths:
  /events:
    get:
      operationId: "listEvents"
      responses:
        "200":
          description: "A success response with all events."
          content:
            application/json:
              schema:
                type: "array"
                items:
                  $ref: "#/components/schemas/Event"
    post:
      operationId: "createEvent"
      requestBody:
        description: "The event to create."
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Event'
      responses:
        '201':
          description: "A success indicating the event was created."
        '400':
          description: "A failure indicating the event wasn't created."
components:
  schemas:
    Event:
      type: "object"
      description: "An event."
      properties:
        name:
          type: "string"
          description: "The event's name."
        date:
          type: "string"
          format: "date"
          description: "The day of the event."
        attendee:
          type: "string"
          description: "The name of the person attending the event."
      required:
        - "name"
        - "date"
        - "attendee"

4:35 - EventService initial implementation

import OpenAPIRuntime
import OpenAPIVapor
import Vapor
import EventAPI

@main
struct Service {
  static func main() async throws {
    let application = try await Vapor.Application.make()
    let transport = VaporTransport(routesBuilder: application)

    let service = Service()
    try service.registerHandlers(
      on: transport,
      serverURL: URL(string: "/api")!
    )

    try await application.execute()
  }
}

extension Service: APIProtocol {
  func listEvents(
    _ input: Operations.listEvents.Input
  ) async throws -> Operations.listEvents.Output {
    let events: [Components.Schemas.Event] = [
      .init(name: "Server-Side Swift Conference", date: "26.09.2024", attendee: "Gus"),
      .init(name: "Oktoberfest", date: "21.09.2024", attendee: "Werner"),
    ]

    return .ok(.init(body: .json(events)))
  }

  func createEvent(
    _ input: Operations.createEvent.Input
  ) async throws -> Operations.createEvent.Output {
    return .undocumented(statusCode: 501, .init())
  }
}

6:56 - EventService Package.swift

// swift-tools-version:5.9
import PackageDescription

let package = Package(
  name: "EventService",
  platforms: [.macOS(.v14)],
  dependencies: [
    .package(
      url: "https://github.com/apple/swift-openapi-generator",
      from: "1.2.1"
    ),
    .package(
      url: "https://github.com/apple/swift-openapi-runtime",
      from: "1.4.0"
    ),
    .package(
      url: "https://github.com/vapor/vapor",
      from: "4.99.2"
    ),
    .package(
      url: "https://github.com/swift-server/swift-openapi-vapor",
      from: "1.0.1"
    ),
    .package(
      url: "https://github.com/vapor/postgres-nio",
      from: "1.19.1"
    ),
  ],
  targets: [
    .target(
      name: "EventAPI",
      dependencies: [
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
      ],
      plugins: [
        .plugin(
          name: "OpenAPIGenerator",
          package: "swift-openapi-generator"
        )
      ]
    ),
    .executableTarget(
      name: "EventService",
      dependencies: [
        "EventAPI",
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
        .product(
          name: "OpenAPIVapor",
          package: "swift-openapi-vapor"
        ),
        .product(
          name: "Vapor",
          package: "vapor"
        ),
        .product(
            name: "PostgresNIO",
          package: "postgres-nio"
        ),
      ]
    ),
  ]
)

7:08 - Implementing the listEvents method

import OpenAPIRuntime
import OpenAPIVapor
import Vapor
import EventAPI
import PostgresNIO

@main
struct Service {
  let postgresClient: PostgresClient
  
  static func main() async throws {
    let application = try await Vapor.Application.make()
    let transport = VaporTransport(routesBuilder: application)

    let postgresClient = PostgresClient(
      configuration: .init(
        host: "localhost",
        username: "postgres",
        password: nil,
        database: nil,
        tls: .disable
      )
    )
    let service = Service(postgresClient: postgresClient)
    try service.registerHandlers(
      on: transport,
      serverURL: URL(string: "/api")!
    )

    try await withThrowingDiscardingTaskGroup { group in
      group.addTask {
        await postgresClient.run()
      }

      group.addTask {
        try await application.execute()
      }
    }
  }
}

extension Service: APIProtocol {
  func listEvents(
    _ input: Operations.listEvents.Input
  ) async throws -> Operations.listEvents.Output {
    let rows = try await self.postgresClient.query("SELECT name, date, attendee FROM events")

    var events = [Components.Schemas.Event]()
    for try await (name, date, attendee) in rows.decode((String, String, String).self) {
      events.append(.init(name: name, date: date, attendee: attendee))
    }

    return .ok(.init(body: .json(events)))
  }

  func createEvent(
    _ input: Operations.createEvent.Input
  ) async throws -> Operations.createEvent.Output {
    return .undocumented(statusCode: 501, .init())
  }
}

9:02 - Implementing the createEvent method

func createEvent(
  _ input: Operations.createEvent.Input
) async throws -> Operations.createEvent.Output {
  switch input.body {
  case .json(let event):
    try await self.postgresClient.query(
      """
      INSERT INTO events (name, date, attendee)
      VALUES (\(event.name), \(event.date), \(event.attendee))
      """
    )
    return .created(.init())
  }
}

11:34 - Instrumenting the listEvents method

func listEvents(
  _ input: Operations.listEvents.Input
) async throws -> Operations.listEvents.Output {
  let logger = Logger(label: "ListEvents")
  logger.info("Handling request", metadata: ["operation": "\(Operations.listEvents.id)"])

  Counter(label: "list.events.counter").increment()

  return try await withSpan("database query") { span in
    let rows = try await postgresClient.query("SELECT name, date, attendee FROM events")
    return try await .ok(.init(body: .json(decodeEvents(rows))))
  }
}

13:14 - EventService Package.swift

// swift-tools-version:5.9
import PackageDescription

let package = Package(
  name: "EventService",
  platforms: [.macOS(.v14)],
  dependencies: [
    .package(
      url: "https://github.com/apple/swift-openapi-generator",
      from: "1.2.1"
    ),
    .package(
      url: "https://github.com/apple/swift-openapi-runtime",
      from: "1.4.0"
    ),
    .package(
      url: "https://github.com/vapor/vapor",
      from: "4.99.2"
    ),
    .package(
      url: "https://github.com/swift-server/swift-openapi-vapor",
      from: "1.0.1"
    ),
    .package(
      url: "https://github.com/vapor/postgres-nio",
      from: "1.19.1"
    ),
    .package(
        url: "https://github.com/apple/swift-log",
        from: "1.5.4"
    ),
  ],
  targets: [
    .target(
      name: "EventAPI",
      dependencies: [
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
      ],
      plugins: [
        .plugin(
          name: "OpenAPIGenerator",
          package: "swift-openapi-generator"
        )
      ]
    ),
    .executableTarget(
      name: "EventService",
      dependencies: [
        "EventAPI",
        .product(
          name: "OpenAPIRuntime",
          package: "swift-openapi-runtime"
        ),
        .product(
          name: "OpenAPIVapor",
          package: "swift-openapi-vapor"
        ),
        .product(
          name: "Vapor",
          package: "vapor"
        ),
        .product(
            name: "PostgresNIO",
          package: "postgres-nio"
        ),
        .product(
            name: "Logging",
            package: "swift-log"
        ),
      ]
    ),
  ]
)

13:38 - Adding logging to the createEvent method

func createEvent(
  _ input: Operations.createEvent.Input
) async throws -> Operations.createEvent.Output {
  switch input.body {
  case .json(let event):
    do {
      try await self.postgresClient.query(
        """
        INSERT INTO events (name, date, attendee)
        VALUES (\(event.name), \(event.date), \(event.attendee))
        """
      )
      return .created(.init())
    } catch let error as PSQLError {
      let logger = Logger(label: "CreateEvent")

      if let message = error.serverInfo?[.message] {
        logger.info(
          "Failed to create event",
          metadata: ["error.message": "\(message)"]
        )
      }
      
      return .badRequest(.init())
    }
  }
}