Bump minimum Swift to 5.9, adopt StrictConcurrency=complete, add GitHub Actions CI (#15)

### Motivation

Although this package is still WIP and has no releases, it would still
be good for it to line up with the rest of the ecosystem with its
supported Swift versions, adoption of strict concurrency, and its CI
support.

### Modifications

- Bump minimum Swift version to 5.9.
- Add `StrictConcurrency=complete` flag and fix test to remove warning.
- Add the standard set of GitHub Actions workflows.
- Format the code to satisfy the license and format checks.

### Result:

Ready for strict concurrency and has CI.

Author: simonjbeaumont

.github/release.yml

@@ -0,0 +1,14 @@
+changelog:
+  categories:
+    - title: SemVer Major
+      labels:
+        - ⚠️ semver/major
+    - title: SemVer Minor
+      labels:
+        - semver/minor
+    - title: SemVer Patch
+      labels:
+        - semver/patch
+    - title: Other Changes
+      labels:
+        - semver/none

.github/workflows/main.yml

@@ -0,0 +1,18 @@
+name: Main
+
+on:
+  push:
+    branches: [main]
+  schedule:
+    - cron: "0 8,20 * * *"
+
+jobs:
+  unit-tests:
+    name: Unit tests
+    uses: apple/swift-nio/.github/workflows/unit_tests.yml@main
+    with:
+      linux_5_9_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_5_10_arguments_override: --explicit-target-dependency-import-check error"
+      linux_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"

.github/workflows/pull_request.yml

@@ -0,0 +1,58 @@
+name: PR
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+
+jobs:
+  soundness:
+    name: Soundness
+    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+    with:
+      license_header_check_project_name: "swift-etcd-client-gsoc"
+
+  unit-tests:
+    name: Unit tests
+    uses: apple/swift-nio/.github/workflows/unit_tests.yml@main
+    with:
+      linux_5_9_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_5_10_arguments_override: "--explicit-target-dependency-import-check error"
+      linux_6_0_arguments_override: "-Xswiftc -warnings-as-errors --explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_nightly_6_0_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+      linux_nightly_main_arguments_override: "--explicit-target-dependency-import-check error -Xswiftc -require-explicit-sendable"
+
+  # Integration tests use a running etcd so this job uses a service container.
+  integration-tests:
+    name: Integration tests
+    runs-on: ubuntu-latest
+    services:
+      etcd:
+        image: quay.io/coreos/etcd:v3.5.6
+        env:
+          ETCD_ADVERTISE_CLIENT_URLS: http://0.0.0.0:2379
+          ETCD_LISTEN_CLIENT_URLS: http://0.0.0.0:2379
+          ETCD_INITIAL_CLUSTER_STATE: new
+        ports:
+          - 2379:2379
+    container:
+      image: swift:6.0-noble
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Build package
+        run: swift build --build-tests
+      - name: Run integration tests
+        shell: bash  # explicitly choose bash, which ensures -o pipefail
+        run: swift test --filter "IntegrationTests" | tee test.out
+        env:
+          SWIFT_ETCD_CLIENT_INTEGRATION_TEST_ENABLED: true
+          ETCD_HOST: etcd
+          ETCD_PORT: 2379
+      - name: Check integration tests actually did run
+        run: test -r test.out && ! grep -i -e "executed 0 tests" -e "skipped" test.out
+
+  cxx-interop:
+    name: Cxx interop
+    uses: apple/swift-nio/.github/workflows/cxx_interop.yml@main

.github/workflows/pull_request_label.yml

@@ -0,0 +1,18 @@
+name: PR label
+
+on:
+  pull_request:
+    types: [labeled, unlabeled, opened, reopened, synchronize]
+
+jobs:
+  semver-label-check:
+    name: Semantic version label check
+    runs-on: ubuntu-latest
+    timeout-minutes: 1
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Check for Semantic Version label
+        uses: apple/swift-nio/.github/actions/pull_request_semver_label_checker@main

.licenseignore

@@ -0,0 +1,40 @@
+.gitignore
+**/.gitignore
+.licenseignore
+.gitattributes
+.git-blame-ignore-revs
+.mailfilter
+.mailmap
+.spi.yml
+.swiftformat
+.swift-format
+.swiftformatignore
+.editorconfig
+.github/*
+*.md
+*.txt
+*.yml
+*.yaml
+*.json
+*.proto
+*.pb.swift
+*.grpc.swift
+Package.swift
+**/Package.swift
+Package@-*.swift
+**/Package@-*.swift
+Package.resolved
+**/Package.resolved
+Makefile
+*.modulemap
+**/*.modulemap
+**/*.docc/*
+*.xcprivacy
+**/*.xcprivacy
+*.symlink
+**/*.symlink
+Dockerfile
+**/Dockerfile
+Snippets/*
+dev/git.commit.template
+.unacceptablelanguageignore

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 5.7
+// swift-tools-version: 5.9
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the swift-etcd-client-gsoc open source project
@@ -27,7 +27,7 @@ let package = Package(
         .library(
             name: "ETCD",
             targets: ["ETCD"]
-        ),
+        )
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.56.0"),
@@ -59,3 +59,9 @@ let package = Package(
         ),
     ]
 )
+
+for target in package.targets {
+    var settings = target.swiftSettings ?? []
+    settings.append(.enableExperimentalFeature("StrictConcurrency=complete"))
+    target.swiftSettings = settings
+}

Sources/ETCD/DeleteRangeRequest.swift

@@ -19,13 +19,13 @@ public struct DeleteRangeRequest {
     public var key: Data
     public var rangeEnd: Data?
     public var prevKV: Bool = false
-    
+
     init(protoDeleteRangeRequest: Etcdserverpb_DeleteRangeRequest) {
         self.key = protoDeleteRangeRequest.key
         self.rangeEnd = protoDeleteRangeRequest.rangeEnd.isEmpty ? nil : protoDeleteRangeRequest.rangeEnd
         self.prevKV = protoDeleteRangeRequest.prevKv
     }
-    
+
     /// Struct representing a deleteRangeRequest in etcd.
     ///
     /// - Parameters:
@@ -37,7 +37,7 @@ public struct DeleteRangeRequest {
         self.rangeEnd = rangeEnd
         self.prevKV = prevKV
     }
-    
+
     func toProto() -> Etcdserverpb_DeleteRangeRequest {
         var protoDeleteRangeRequest = Etcdserverpb_DeleteRangeRequest()
         protoDeleteRangeRequest.key = self.key

Sources/ETCD/ETCDClient.swift

@@ -110,7 +110,10 @@ public final class EtcdClient: @unchecked Sendable {
     /// - Parameters:
     ///   - key: The key for which the value is watched. Parameter is of type Sequence<UInt8>.
     ///   - operation: The operation to be run on the WatchAsyncSequence for the key.
-    public func watch<Result>(_ key: some Sequence<UInt8>, _ operation: (WatchAsyncSequence) async throws -> Result) async throws -> Result {
+    public func watch<Result>(
+        _ key: some Sequence<UInt8>,
+        _ operation: (WatchAsyncSequence) async throws -> Result
+    ) async throws -> Result {
         let request = [Etcdserverpb_WatchRequest.with { $0.createRequest.key = Data(key) }]
         let watchAsyncSequence = WatchAsyncSequence(grpcAsyncSequence: watchClient.watch(request))
         return try await operation(watchAsyncSequence)
@@ -121,7 +124,10 @@ public final class EtcdClient: @unchecked Sendable {
     /// - Parameters:
     ///   - key: The key for which the value is watched. Parameter is of type String.
     ///   - operation: The operation to be run on the WatchAsyncSequence for the key.
-    public func watch<Result>(_ key: String, _ operation: (WatchAsyncSequence) async throws -> Result) async throws -> Result {
+    public func watch<Result>(
+        _ key: String,
+        _ operation: (WatchAsyncSequence) async throws -> Result
+    ) async throws -> Result {
         try await watch(key.utf8, operation)
     }
 }

Sources/ETCDExample/ETCDExample.swift

@@ -1,5 +1,3 @@
-import Dispatch
-
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the swift-etcd-client-gsoc open source project
@@ -13,6 +11,8 @@ import Dispatch
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+
+import Dispatch
 import ETCD
 import NIO
 

Tests/ETCDTests/ETCDTests.swift renamed to Tests/IntegrationTests/IntegrationTests.swift

@@ -1,6 +1,3 @@
-import ETCD
-import NIO
-
 //===----------------------------------------------------------------------===//
 //
 // This source file is part of the swift-etcd-client-gsoc open source project
@@ -14,18 +11,22 @@ import NIO
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+
+import ETCD
+import NIO
 import XCTest
 
-final class EtcdClientTests: XCTestCase {
-    var eventLoopGroup: EventLoopGroup!
-    var etcdClient: EtcdClient!
+final class IntegrationTests: XCTestCase {
+
+    private static let integrationTestEnabled = getBoolEnv("SWIFT_ETCD_CLIENT_INTEGRATION_TEST_ENABLED") ?? false
 
     override func setUp() async throws {
-        eventLoopGroup = MultiThreadedEventLoopGroup.singleton
-        etcdClient = EtcdClient(host: "localhost", port: 2379, eventLoopGroup: eventLoopGroup)
+        try XCTSkipUnless(Self.integrationTestEnabled)
     }
 
     func testSetAndGetStringValue() async throws {
+        let etcdClient = EtcdClient.testClient
+
         try await etcdClient.set("testKey", value: "testValue")
         let key = "testKey".data(using: .utf8)!
         let rangeRequest = RangeRequest(key: key)
@@ -36,13 +37,17 @@ final class EtcdClientTests: XCTestCase {
     }
 
     func testGetNonExistentKey() async throws {
+        let etcdClient = EtcdClient.testClient
+
         let key = "nonExistentKey".data(using: .utf8)!
         let rangeRequest = RangeRequest(key: key)
         let result = try await etcdClient.getRange(rangeRequest)
         XCTAssertNil(result)
     }
 
     func testDeleteKeyExists() async throws {
+        let etcdClient = EtcdClient.testClient
+
         let key = "testKey"
         let value = "testValue"
         try await etcdClient.set(key, value: value)
@@ -54,12 +59,14 @@ final class EtcdClientTests: XCTestCase {
 
         let deleteRangeRequest = DeleteRangeRequest(key: rangeRequestKey)
         try await etcdClient.deleteRange(deleteRangeRequest)
-        
+
         fetchedValue = try await etcdClient.getRange(rangeRequest)
         XCTAssertNil(fetchedValue)
     }
 
     func testDeleteNonExistentKey() async throws {
+        let etcdClient = EtcdClient.testClient
+
         let key = "testKey".data(using: .utf8)!
         let rangeRequest = RangeRequest(key: key)
 
@@ -68,12 +75,14 @@ final class EtcdClientTests: XCTestCase {
 
         let deleteRangeRequest = DeleteRangeRequest(key: key)
         try await etcdClient.deleteRange(deleteRangeRequest)
-        
+
         fetchedValue = try await etcdClient.getRange(rangeRequest)
         XCTAssertNil(fetchedValue)
     }
 
     func testUpdateExistingKey() async throws {
+        let etcdClient = EtcdClient.testClient
+
         let key = "testKey"
         let value = "testValue"
         try await etcdClient.set(key, value: value)
@@ -95,14 +104,16 @@ final class EtcdClientTests: XCTestCase {
     }
 
     func testWatch() async throws {
+        let etcdClient = EtcdClient.testClient
+
         let key = "testKey"
         let value = "testValue".data(using: .utf8)!
 
         try await etcdClient.put(key, value: "foo")
 
         try await withThrowingTaskGroup(of: Void.self) { group in
             group.addTask {
-                try await self.etcdClient.watch(key) { watchAsyncSequence in
+                try await etcdClient.watch(key) { watchAsyncSequence in
                     var iterator = watchAsyncSequence.makeAsyncIterator()
                     let events = try await iterator.next()
                     guard let events = events else {
@@ -122,8 +133,27 @@ final class EtcdClientTests: XCTestCase {
             }
 
             try await Task.sleep(nanoseconds: 1_000_000_000)
-            try await self.etcdClient.put(key, value: String(data: value, encoding: .utf8)!)
+            try await etcdClient.put(key, value: String(data: value, encoding: .utf8)!)
             group.cancelAll()
         }
     }
 }
+
+extension EtcdClient {
+    fileprivate static let testClient = EtcdClient(
+        host: ProcessInfo.processInfo.environment["ETCD_HOST"] ?? "localhost",
+        port: getIntEnv("ETCD_PORT") ?? 2379,
+        eventLoopGroup: .singletonMultiThreadedEventLoopGroup
+    )
+}
+
+/// Returns true if `key` is a truthy string, otherwise returns false.
+private func getBoolEnv(_ key: String) -> Bool? {
+    switch ProcessInfo.processInfo.environment[key]?.lowercased() {
+    case .none: return nil
+    case "true", "y", "yes", "on", "1": return true
+    default: return false
+    }
+}
+
+private func getIntEnv(_ key: String) -> Int? { ProcessInfo.processInfo.environment[key].flatMap(Int.init(_:)) }