+sample DistributedBuilds a fun example pretending to be a "jenkins"-like thing

.gitignore

@@ -3,6 +3,7 @@
 
 *.orig
 *.app
+.history
 
 Instruments/ActorInstruments/ActorInstruments.xcodeproj/xcuserdata
 Instruments/ActorInstruments/build/

Package.swift

@@ -39,11 +39,13 @@ var targets: [PackageDescription.Target] = [
             .product(name: "NIOSSL", package: "swift-nio-ssl"),
             .product(name: "NIOExtras", package: "swift-nio-extras"),
             .product(name: "SwiftProtobuf", package: "swift-protobuf"),
-            .product(name: "Logging", package: "swift-log"),
-            .product(name: "Metrics", package: "swift-metrics"),
             .product(name: "ServiceDiscovery", package: "swift-service-discovery"),
             .product(name: "Backtrace", package: "swift-backtrace"),
             .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
+            // Observability
+            .product(name: "Logging", package: "swift-log"),
+            .product(name: "Metrics", package: "swift-metrics"),
+            .product(name: "Tracing", package: "swift-distributed-tracing"),
         ]
     ),
 
@@ -182,7 +184,8 @@ var dependencies: [Package.Dependency] = [
     .package(url: "https://github.com/apple/swift-collections", from: "1.0.1"),
 
     // ~~~ Observability ~~~
-    .package(url: "https://github.com/apple/swift-log", from: "1.0.0"),
+    .package(url: "https://github.com/apple/swift-log", from: "1.4.0"),
+    .package(url: "https://github.com/apple/swift-distributed-tracing", from: "0.3.0"),
     // swift-metrics 1.x and 2.x are almost API compatible, so most clients should use
     .package(url: "https://github.com/apple/swift-metrics", "1.0.0" ..< "3.0.0"),
     .package(url: "https://github.com/apple/swift-service-discovery", from: "1.0.0"),

Samples/Package.swift

@@ -21,6 +21,7 @@ var targets: [PackageDescription.Target] = [
         name: "SampleDiningPhilosophers",
         dependencies: [
             .product(name: "DistributedCluster", package: "swift-distributed-actors"),
+            "_PrettyLogHandler",
         ],
         path: "Sources/SampleDiningPhilosophers",
         exclude: [
@@ -29,6 +30,33 @@ var targets: [PackageDescription.Target] = [
         ]
     ),
 
+    .executableTarget(
+        name: "SampleClusterTracing",
+        dependencies: [
+            .product(name: "DistributedCluster", package: "swift-distributed-actors"),
+            .product(name: "OpenTelemetry", package: "opentelemetry-swift"),
+            .product(name: "OtlpGRPCSpanExporting", package: "opentelemetry-swift"),
+            "_PrettyLogHandler",
+        ]
+    ),
+
+    .executableTarget(
+        name: "SampleClusterBuilds",
+        dependencies: [
+            .product(name: "DistributedCluster", package: "swift-distributed-actors"),
+            .product(name: "OpenTelemetry", package: "opentelemetry-swift"),
+            .product(name: "OtlpGRPCSpanExporting", package: "opentelemetry-swift"),
+            "_PrettyLogHandler",
+        ]
+    ),
+
+    .target(
+        name: "_PrettyLogHandler",
+        dependencies: [
+            .product(name: "DistributedCluster", package: "swift-distributed-actors"),
+        ]
+    ),
+
     /* --- tests --- */
 
     // no-tests placeholder project to not have `swift test` fail on Samples/
@@ -45,6 +73,7 @@ var dependencies: [Package.Dependency] = [
     .package(name: "swift-distributed-actors", path: "../"),
 
     // ~~~~~~~ only for samples ~~~~~~~
+    .package(url: "https://github.com/slashmo/opentelemetry-swift", from: "0.3.0"),
 ]
 
 let package = Package(
@@ -58,11 +87,14 @@ let package = Package(
     ],
     products: [
         /* ---  samples --- */
-
         .executable(
             name: "SampleDiningPhilosophers",
             targets: ["SampleDiningPhilosophers"]
         ),
+        .executable(
+            name: "SampleClusterTracing",
+            targets: ["SampleClusterTracing"]
+        ),
     ],
 
     dependencies: dependencies,

Samples/Sources/SampleClusterBuilds/ClusterBuilds.swift

@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import _PrettyLogHandler
+import Distributed
+import DistributedCluster
+import Logging
+import NIO
+import OpenTelemetry
+import OtlpGRPCSpanExporting
+import Tracing
+
+struct ClusterBuilds {
+    let system: ClusterSystem
+    var workers: [ActorID: BuildWorker] = [:]
+
+    init(name: String, port: Int) async {
+        self.system = await ClusterSystem(name) { settings in
+            settings.bindPort = port
+
+            settings.plugins.install(plugin: ClusterSingletonPlugin())
+
+            // We are purposefully making allowing long calls:
+            settings.remoteCall.defaultTimeout = .seconds(20)
+
+            // Try joining this seed node automatically; once we have joined at least once node, we'll learn about others.
+            settings.discovery = ServiceDiscoverySettings(static: [
+                Main.Config.seedEndpoint,
+            ])
+        }
+        self.system.cluster.join(endpoint: Main.Config.seedEndpoint)
+    }
+
+    mutating func run(tasks: Int) async throws {
+        var singletonSettings = ClusterSingletonSettings()
+        singletonSettings.allocationStrategy = .byLeadership
+
+        // Pretend we have some work to do:
+        let buildTasks: [BuildTask] = (0 ..< tasks).map { _ in BuildTask() }
+
+        // anyone can host the singleton, but by default, it'll be on the build leader (7330) various strategies are possible.
+        try await system.singleton.host(name: BuildLeader.singletonName) { actorSystem in
+            await BuildLeader(buildTasks: buildTasks, actorSystem: actorSystem)
+        }
+
+        // all nodes, except the build-leader node contain a few workers:
+        if self.system.isBuildWorker {
+            for _ in 0 ..< Main.Config.workersPerNode {
+                await makeWorker()
+            }
+        }
+    }
+
+    private mutating func makeWorker() async {
+        let worker = await BuildWorker(actorSystem: self.system)
+        self.workers[worker.id] = worker
+    }
+}

Samples/Sources/SampleClusterBuilds/Convenience/Clock+Extensions.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import _PrettyLogHandler
+import Distributed
+import DistributedCluster
+import Logging
+import NIO
+import OpenTelemetry
+import OtlpGRPCSpanExporting
+import Tracing
+
+// Sleep, with adding a little bit of noise (additional delay) to the duration.
+func noisySleep(for duration: ContinuousClock.Duration) async {
+    var duration = duration + .milliseconds(Int.random(in: 200 ..< 500))
+    try? await Task.sleep(until: ContinuousClock.now + duration, clock: .continuous)
+}

Samples/Sources/SampleClusterBuilds/Convenience/Roles.swift

@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import _PrettyLogHandler
+import Distributed
+import DistributedCluster
+import Logging
+import NIO
+import OpenTelemetry
+import OtlpGRPCSpanExporting
+import Tracing
+
+// TODO: we want to support "member roles" in membership, this would be then a built in query, and not hardcoded by port either.
+extension ClusterSystem {
+    var isBuildLeader: Bool {
+        self.cluster.endpoint.port == 7330
+    }
+
+    var isBuildWorker: Bool {
+        self.cluster.endpoint.port > 7330
+    }
+}

Samples/Sources/SampleClusterBuilds/Convenience/Weak.swift

@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Distributed
+import DistributedCluster
+
+final class Weak<Act: DistributedActor> {
+    weak var actor: Act?
+
+    init(_ actor: Act) {
+        self.actor = actor
+    }
+
+    init(idForRemoval id: ClusterSystem.ActorID) {
+        self.actor = nil
+    }
+}

Samples/Sources/SampleClusterBuilds/DefaultActorSystem.swift

@@ -0,0 +1,18 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Distributed
+import DistributedCluster
+
+typealias DefaultDistributedActorSystem = ClusterSystem

Samples/Sources/SampleClusterBuilds/Model.swift

@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift Distributed Actors open source project
+//
+// Copyright (c) 2018-2022 Apple Inc. and the Swift Distributed Actors project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.md for the list of Swift Distributed Actors project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import _PrettyLogHandler
+import Distributed
+import DistributedCluster
+import struct Foundation.UUID
+import Logging
+import NIO
+import OpenTelemetry
+import OtlpGRPCSpanExporting
+import Tracing
+
+struct BuildTask: Sendable, Codable, Hashable {
+    let id: BuildTaskID
+
+    // this would have some state about "what to build"
+
+    init() {
+        self.id = .init()
+    }
+
+    init(id: BuildTaskID) {
+        self.id = id
+    }
+}
+
+/// A trivial "build result" representation, not carrying additional information, just for demonstration purposes.
+enum BuildResult: Sendable, Codable, Equatable {
+    case successful
+    case failed
+    case rejected
+}
+
+struct BuildTaskID: Sendable, Codable, Hashable, CustomStringConvertible {
+    let id: UUID
+    init() {
+        self.id = UUID()
+    }
+
+    var description: String {
+        "\(id)"
+    }
+}