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| 1 | +/* |
| 2 | + * Copyright 2024, gRPC Authors All rights reserved. |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | + * you may not use this file except in compliance with the License. |
| 6 | + * You may obtain a copy of the License at |
| 7 | + * |
| 8 | + * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | + * |
| 10 | + * Unless required by applicable law or agreed to in writing, software |
| 11 | + * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | + * See the License for the specific language governing permissions and |
| 14 | + * limitations under the License. |
| 15 | + */ |
| 16 | + |
| 17 | +private import GRPCCore |
| 18 | + |
| 19 | +extension ResolvableTargets { |
| 20 | + /// A resolvable target for addresses which can be resolved via DNS. |
| 21 | + /// |
| 22 | + /// If you already have an IPv4 or IPv6 address use ``ResolvableTargets/IPv4`` and |
| 23 | + /// ``ResolvableTargets/IPv6`` respectively. |
| 24 | + public struct DNS: ResolvableTarget, Sendable { |
| 25 | + /// The host to resolve via DNS. |
| 26 | + public var host: String |
| 27 | + |
| 28 | + /// The port to use with resolved addresses. |
| 29 | + public var port: Int |
| 30 | + |
| 31 | + /// Create a new DNS target. |
| 32 | + /// - Parameters: |
| 33 | + /// - host: The host to resolve via DNS. |
| 34 | + /// - port: The port to use with resolved addresses. |
| 35 | + public init(host: String, port: Int) { |
| 36 | + self.host = host |
| 37 | + self.port = port |
| 38 | + } |
| 39 | + } |
| 40 | +} |
| 41 | + |
| 42 | +extension ResolvableTarget where Self == ResolvableTargets.DNS { |
| 43 | + /// Creates a new resolvable DNS target. |
| 44 | + /// - Parameters: |
| 45 | + /// - host: The host address to resolve. |
| 46 | + /// - port: The port to use for each resolved address. |
| 47 | + /// - Returns: A ``ResolvableTarget``. |
| 48 | + public static func dns(host: String, port: Int = 443) -> Self { |
| 49 | + return Self(host: host, port: port) |
| 50 | + } |
| 51 | +} |
| 52 | + |
| 53 | +@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *) |
| 54 | +extension NameResolvers { |
| 55 | + /// A ``NameResolverFactory`` for ``ResolvableTargets/DNS`` targets. |
| 56 | + public struct DNS: NameResolverFactory { |
| 57 | + public typealias Target = ResolvableTargets.DNS |
| 58 | + |
| 59 | + /// Create a new DNS name resolver factory. |
| 60 | + public init() {} |
| 61 | + |
| 62 | + public func resolver(for target: Target) -> NameResolver { |
| 63 | + let resolver = Self.Resolver(target: target) |
| 64 | + return NameResolver(names: RPCAsyncSequence(wrapping: resolver), updateMode: .pull) |
| 65 | + } |
| 66 | + } |
| 67 | +} |
| 68 | + |
| 69 | +@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *) |
| 70 | +extension NameResolvers.DNS { |
| 71 | + struct Resolver: Sendable { |
| 72 | + var target: ResolvableTargets.DNS |
| 73 | + |
| 74 | + init(target: ResolvableTargets.DNS) { |
| 75 | + self.target = target |
| 76 | + } |
| 77 | + |
| 78 | + func resolve( |
| 79 | + isolation actor: isolated (any Actor)? = nil |
| 80 | + ) async throws -> NameResolutionResult { |
| 81 | + let addresses: [SocketAddress] |
| 82 | + |
| 83 | + do { |
| 84 | + addresses = try await DNSResolver.resolve(host: self.target.host, port: self.target.port) |
| 85 | + } catch let error as CancellationError { |
| 86 | + throw error |
| 87 | + } catch { |
| 88 | + throw RPCError( |
| 89 | + code: .internalError, |
| 90 | + message: "Couldn't resolve address for \(self.target.host):\(self.target.port)", |
| 91 | + cause: error |
| 92 | + ) |
| 93 | + } |
| 94 | + |
| 95 | + return NameResolutionResult(endpoints: [Endpoint(addresses: addresses)], serviceConfig: nil) |
| 96 | + } |
| 97 | + } |
| 98 | +} |
| 99 | + |
| 100 | +@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, visionOS 2.0, *) |
| 101 | +extension NameResolvers.DNS.Resolver: AsyncSequence { |
| 102 | + typealias Element = NameResolutionResult |
| 103 | + |
| 104 | + func makeAsyncIterator() -> AsyncIterator { |
| 105 | + return AsyncIterator(resolver: self) |
| 106 | + } |
| 107 | + |
| 108 | + struct AsyncIterator: AsyncIteratorProtocol { |
| 109 | + typealias Element = NameResolutionResult |
| 110 | + |
| 111 | + private let resolver: NameResolvers.DNS.Resolver |
| 112 | + |
| 113 | + init(resolver: NameResolvers.DNS.Resolver) { |
| 114 | + self.resolver = resolver |
| 115 | + } |
| 116 | + |
| 117 | + func next() async throws -> NameResolutionResult? { |
| 118 | + return try await self.next(isolation: nil) |
| 119 | + } |
| 120 | + |
| 121 | + func next( |
| 122 | + isolation actor: isolated (any Actor)? |
| 123 | + ) async throws(any Error) -> NameResolutionResult? { |
| 124 | + return try await self.resolver.resolve(isolation: actor) |
| 125 | + } |
| 126 | + } |
| 127 | +} |
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