Migrate to swift 6.0 & swift-gRPC 2.0

The following migrates to swift 6.0, and also
migrate to swift-grpc 2.0 that uses swift-nio
under the hood to provide nicer API and async await

Author: mustiikhalil

.github/workflows/build.yml

@@ -495,7 +495,7 @@ jobs:
     name: Test Swift Linux
     strategy:
       matrix:
-        swift: ["5.10", "6.1", "6.2"]
+        swift: ["6.0", "6.1", "6.2"]
     runs-on: ubuntu-24.04
     steps:
     - uses: actions/checkout@v6

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.10
+// swift-tools-version:6.0
 /*
  * Copyright 2020 Google Inc. All rights reserved.
  *
@@ -36,14 +36,17 @@ let package = Package(
     .target(
       name: "FlatBuffers",
       dependencies: ["Common"],
-      path: "swift/Sources/FlatBuffers"),
+      path: "swift/Sources/FlatBuffers",
+      swiftSettings: .settings),
     .target(
       name: "FlexBuffers",
       dependencies: ["Common"],
-      path: "swift/Sources/FlexBuffers"),
+      path: "swift/Sources/FlexBuffers",
+      swiftSettings: .settings),
     .target(
       name: "Common",
-      path: "swift/Sources/Common"),
+      path: "swift/Sources/Common",
+      swiftSettings: .settings),
     .testTarget(
       name: "FlatbuffersTests",
       dependencies: .dependencies,
@@ -52,15 +55,27 @@ let package = Package(
       name: "FlexbuffersTests",
       dependencies: ["FlexBuffers"],
       path: "tests/swift/Tests/Flexbuffers"),
-  ])
+  ],
+  swiftLanguageModes: [.v6])
+
+extension Array where Element == SwiftSetting {
+  static var settings: [SwiftSetting] {
+    [.enableUpcomingFeature("ExistentialAny")]
+  }
+}
 
 extension Array where Element == Package.Dependency {
   static var dependencies: [Package.Dependency] {
     #if os(Windows)
     []
     #else
     // Test only Dependency
-    [.package(url: "https://github.com/grpc/grpc-swift.git", from: "1.4.1")]
+    [
+      .package(url: "https://github.com/grpc/grpc-swift-2.git", from: "2.0.0"),
+      .package(
+        url: "https://github.com/grpc/grpc-swift-nio-transport.git",
+        from: "2.0.0"),
+    ]
     #endif
   }
 }
@@ -72,7 +87,10 @@ extension Array where Element == PackageDescription.Target.Dependency {
     #else
     // Test only Dependency
     [
-      .product(name: "GRPC", package: "grpc-swift"),
+      .product(name: "GRPCCore", package: "grpc-swift-2"),
+      .product(
+        name: "GRPCNIOTransportHTTP2",
+        package: "grpc-swift-nio-transport"),
       "FlatBuffers",
     ]
     #endif

grpc/examples/greeter_v2.fbs

@@ -0,0 +1,16 @@
+namespace models;
+
+table HelloResponse {
+  message:string;
+}
+
+table HelloRequest {
+  name:string;
+}
+
+rpc_service Greeter {
+  Get(HelloRequest):HelloResponse;
+  Collect(HelloRequest):HelloResponse (streaming: "client");
+  Expand(HelloRequest):HelloResponse (streaming: "server");
+  Update(HelloRequest):HelloResponse (streaming: "bidi");
+}

grpc/examples/swift/Greeter/Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.10
+// swift-tools-version:6.2
 /*
  * Copyright 2020 Google Inc. All rights reserved.
  *
@@ -20,39 +20,43 @@ import PackageDescription
 let package = Package(
   name: "Greeter",
   platforms: [
-    .iOS(.v12),
-    .macOS(.v10_14),
+    .iOS(.v18),
+    .macOS(.v15),
   ],
   dependencies: [
-    .package(path: "../../../../swift"),
-    .package(url: "https://github.com/grpc/grpc-swift.git", from: "1.0.0"),
+    .package(path: "../../../.."),
+    .package(url: "https://github.com/grpc/grpc-swift-2.git", from: "2.0.0"),
+    .package(
+      url: "https://github.com/grpc/grpc-swift-nio-transport.git",
+      from: "2.0.0"),
+    .package(
+      url: "https://github.com/apple/swift-argument-parser.git",
+      from: "1.5.0"),
   ],
   targets: [
     // Targets are the basic building blocks of a package. A target can define a module or a test suite.
     // Targets can depend on other targets in this package, and on products in packages which this package depends on.
     .target(
-      name: "Model",
+      name: "Models",
       dependencies: [
-        "GRPC",
-        "FlatBuffers",
-      ],
-      path: "Sources/Model"),
+        .product(name: "FlatBuffers", package: "flatbuffers"),
+        .product(name: "GRPCCore", package: "grpc-swift-2"),
+        .product(
+          name: "GRPCNIOTransportHTTP2",
+          package: "grpc-swift-nio-transport"),
+      ]),
 
     // Client for the Greeter example
-    .target(
-      name: "Client",
-      dependencies: [
-        "GRPC",
-        "Model",
-      ],
-      path: "Sources/client"),
-
-    // Server for the Greeter example
-    .target(
-      name: "Server",
+    .executableTarget(
+      name: "Commands",
       dependencies: [
-        "GRPC",
-        "Model",
-      ],
-      path: "Sources/server"),
+        .product(name: "GRPCCore", package: "grpc-swift-2"),
+        .product(
+          name: "GRPCNIOTransportHTTP2",
+          package: "grpc-swift-nio-transport"),
+        .product(
+          name: "ArgumentParser",
+          package: "swift-argument-parser"),
+        "Models",
+      ]),
   ])

grpc/examples/swift/Greeter/Sources/Commands/Commands.swift

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2024 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import ArgumentParser
+
+let port = 3000
+
+@main
+struct GreeterCommand: AsyncParsableCommand {
+  static let configuration = CommandConfiguration(
+    commandName: "greeter",
+    abstract: "A multi-tool to run an echo server and execute RPCs against it.",
+    subcommands: [ServerCommand.self, ClientCommand.self])
+}
+

grpc/examples/swift/Greeter/Sources/Commands/Services/GreeterService.swift

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2024 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import FlatBuffers
+import GRPCCore
+import Models
+
+struct GreeterService: models_Greeter.SimpleServiceProtocol {
+  func Get(
+    request: GRPCMessage<models_HelloResponse>,
+    context: GRPCCore
+      .ServerContext) async throws -> GRPCMessage<models_HelloResponse>
+  {
+    let model = try request.decode()
+    print("## GreeterService.Get: \(model.message)")
+
+    var builder = FlatBufferBuilder(initialSize: 128)
+    let off = builder.create(string: "Hello \(model.message ?? "Unknown")")
+    let root = models_HelloResponse.createHelloResponse(
+      &builder,
+      messageOffset: off)
+    builder.finish(offset: root)
+    return try GRPCMessage<models_HelloResponse>(builder: &builder)
+  }
+
+  func Collect(
+    request: GRPCCore.RPCAsyncSequence<
+      GRPCMessage<models_HelloResponse>,
+      any Swift.Error
+    >,
+    context: GRPCCore
+      .ServerContext) async throws -> GRPCMessage<models_HelloResponse>
+  {
+    let messages: [String] = try await request
+      .reduce(into: []) { array, message in
+        let model = try message.decode()
+        return array.append(model.message ?? "Unknown")
+      }
+
+    let joined = messages.joined(separator: ", ")
+    print("## GreeterService.Collect: \(joined)")
+
+    var builder = FlatBufferBuilder(initialSize: 128)
+    let off = builder.create(string: "Hello \(joined)")
+    let root = models_HelloResponse.createHelloResponse(
+      &builder,
+      messageOffset: off)
+    builder.finish(offset: root)
+    return try GRPCMessage<models_HelloResponse>(builder: &builder)
+  }
+
+  func Expand(
+    request: GRPCMessage<models_HelloResponse>,
+    response: GRPCCore.RPCWriter<GRPCMessage<models_HelloResponse>>,
+    context: GRPCCore.ServerContext) async throws
+  {
+
+    let model = try request.decode()
+    print("## GreeterService.Expand: \(model.message)")
+
+    let message = model.message ?? "Unknown"
+    let stream = AsyncThrowingStream<
+      GRPCMessage<models_HelloResponse>,
+      Error
+    > { continuation in
+      var builder = FlatBufferBuilder(initialSize: 128)
+      for char in message {
+        let off = builder.create(string: "\(char)")
+        let root = models_HelloResponse.createHelloResponse(
+          &builder,
+          messageOffset: off)
+        builder.finish(offset: root)
+
+        do {
+          continuation
+            .yield(try GRPCMessage<models_HelloResponse>(builder: &builder))
+        } catch {
+          continuation.finish(throwing: error)
+        }
+      }
+
+      continuation.finish()
+    }
+    try await response.write(contentsOf: stream)
+  }
+
+  func Update(
+    request: GRPCCore.RPCAsyncSequence<
+      GRPCMessage<models_HelloResponse>,
+      any Swift.Error
+    >,
+    response: GRPCCore.RPCWriter<GRPCMessage<models_HelloResponse>>,
+    context: GRPCCore.ServerContext) async throws
+  {
+    for try await message in request {
+      let model = try message.decode()
+      print("## GreeterService.Update: \(model.message)")
+      var builder = FlatBufferBuilder(initialSize: 128)
+      let off = builder.create(string: "Hello \(model.message ?? "Unknown")")
+      let root = models_HelloResponse.createHelloResponse(
+        &builder,
+        messageOffset: off)
+      builder.finish(offset: root)
+      try await response
+        .write(try GRPCMessage<models_HelloResponse>(builder: &builder))
+    }
+  }
+}