Code generation package plugins

Motivation:

To make code generation more convenient for adopters.

Modifications:

* New build plugin to generate gRPC services and protobuf messages
* New command plugin
  e.g. `swift package generate-grpc-code-from-protos Sources/Protos/HelloWorld.proto`
* Integration tests (incomplete)

This PR also includes a change to `protoc-gen-grpc-swift` itself:
* Generate an empty file if no gRPC services are found in the protobuf definition file. This is required by the build plugin which needs deterministic outputs and matches the behavior of `protoc-gen-swift`.

Result:

* Users will be able to make use of the build and command plugins.
* `protoc-gen-grpc-swift` will Generate an empty file if no gRPC services are found in the protobuf definition file.

.github/workflows/matrices/plugin-tests.json

@@ -0,0 +1 @@
+{"config":[{"name":"Plugin tests (6.0)","swift_version":"6.0","runner":"ubuntu-latest","image":"swift:6.0-jammy","platform":"Linux","setup_command":"apt-get update -y -q && apt-get install -y -q curl protobuf-compiler","command":"curl -s https://raw.githubusercontent.com/grpc/grpc-swift-protobuf/package_plugins/dev/plugin-tests.sh | bash","command_arguments":""},{"name":"Plugin tests (nightly-6.0)","swift_version":"nightly-6.0","runner":"ubuntu-latest","image":"swiftlang/swift:nightly-6.0-jammy","platform":"Linux","setup_command":"apt-get update -y -q && apt-get install -y -q curl protobuf-compiler","command":"curl -s https://raw.githubusercontent.com/grpc/grpc-swift-protobuf/package_plugins/dev/plugin-tests.sh | bash","command_arguments":""},{"name":"Plugin tests (nightly-main)","swift_version":"nightly-main","runner":"ubuntu-latest","image":"swiftlang/swift:nightly-main-jammy","platform":"Linux","setup_command":"apt-get update -y -q && apt-get install -y -q curl protobuf-compiler","command":"curl -s https://raw.githubusercontent.com/grpc/grpc-swift-protobuf/package_plugins/dev/plugin-tests.sh | bash","command_arguments":""}]}

.github/workflows/pull_request.yml

@@ -26,6 +26,13 @@ jobs:
       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"
 
+  plugin-tests:
+    name: Plugin tests
+    uses: apple/swift-nio/.github/workflows/swift_load_test_matrix.yml@main
+    with:
+      name: "Plugin tests"
+      matrix_path: ".github/workflows/matrices/plugin-tests.json"
+
   cxx-interop:
     name: Cxx interop
     uses: apple/swift-nio/.github/workflows/cxx_interop.yml@main

IntegrationTests/PluginTests/test_01_top_level_config_file/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

IntegrationTests/PluginTests/test_01_top_level_config_file/Package.swift

@@ -0,0 +1,51 @@
+// swift-tools-version: 6.0
+/*
+ * Copyright 2024, gRPC Authors 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 PackageDescription
+
+let package = Package(
+  name: "grpc-adopter",
+  platforms: [
+    .macOS(.v15),
+    .iOS(.v18),
+    .tvOS(.v18),
+    .watchOS(.v11),
+    .visionOS(.v2),
+  ],
+  dependencies: [
+    .package(
+      path: "../../../../grpc-swift-protobuf"
+    ),
+    .package(
+      url: "https://github.com/grpc/grpc-swift.git",
+      exact: "2.0.0-beta.2"
+    ),
+  ],
+  targets: [
+    .executableTarget(
+      name: "grpc-adopter",
+      dependencies: [
+        .product(name: "GRPCCore", package: "grpc-swift"),
+        .product(name: "GRPCInProcessTransport", package: "grpc-swift"),
+        .product(name: "GRPCProtobuf", package: "grpc-swift-protobuf"),
+      ],
+      plugins: [
+        .plugin(name: "GRPCGeneratorPlugin", package: "grpc-swift-protobuf")
+      ]
+    )
+  ]
+)

IntegrationTests/PluginTests/test_01_top_level_config_file/Sources/Protos/HelloWorld.proto

@@ -0,0 +1,37 @@
+// Copyright 2015, gRPC Authors 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.
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "io.grpc.examples.helloworld";
+option java_outer_classname = "HelloWorldProto";
+option objc_class_prefix = "HLW";
+
+package helloworld;
+
+// The greeting service definition.
+service Greeter {
+  // Sends a greeting
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}

IntegrationTests/PluginTests/test_01_top_level_config_file/Sources/adopter.swift

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2024, gRPC Authors 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 GRPCCore
+import GRPCInProcessTransport
+import GRPCProtobuf
+
+@main
+struct PluginAdopter {
+  static func main() async throws {
+    let inProcess = InProcessTransport()
+    try await withGRPCServer(transport: inProcess.server, services: [Greeter()]) { server in
+      try await withGRPCClient(transport: inProcess.client) { client in
+        try await Self.doRPC(Helloworld_Greeter.Client(wrapping: client))
+      }
+    }
+  }
+
+  static func doRPC(_ greeter: Helloworld_Greeter.Client) async throws {
+    do {
+      let reply = try await greeter.sayHello(.with { $0.name = "(ignored)" })
+      print("Reply: \(reply.message)")
+    } catch {
+      print("Error: \(error)")
+    }
+  }
+}
+
+struct Greeter: Helloworld_Greeter.SimpleServiceProtocol {
+  func sayHello(
+    request: Helloworld_HelloRequest,
+    context: ServerContext
+  ) async throws -> Helloworld_HelloReply {
+    return .with { reply in
+      reply.message = "Hello, world!"
+    }
+  }
+}

IntegrationTests/PluginTests/test_01_top_level_config_file/Sources/grpc-swift-config.json

@@ -0,0 +1,3 @@
+{
+  "visibility": "internal"
+}

IntegrationTests/PluginTests/test_02_peer_config_file/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

IntegrationTests/PluginTests/test_02_peer_config_file/Package.swift

@@ -0,0 +1,51 @@
+// swift-tools-version: 6.0
+/*
+ * Copyright 2024, gRPC Authors 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 PackageDescription
+
+let package = Package(
+  name: "grpc-adopter",
+  platforms: [
+    .macOS(.v15),
+    .iOS(.v18),
+    .tvOS(.v18),
+    .watchOS(.v11),
+    .visionOS(.v2),
+  ],
+  dependencies: [
+    .package(
+      path: "../../../../grpc-swift-protobuf"
+    ),
+    .package(
+      url: "https://github.com/grpc/grpc-swift.git",
+      exact: "2.0.0-beta.2"
+    ),
+  ],
+  targets: [
+    .executableTarget(
+      name: "grpc-adopter",
+      dependencies: [
+        .product(name: "GRPCCore", package: "grpc-swift"),
+        .product(name: "GRPCInProcessTransport", package: "grpc-swift"),
+        .product(name: "GRPCProtobuf", package: "grpc-swift-protobuf"),
+      ],
+      plugins: [
+        .plugin(name: "GRPCGeneratorPlugin", package: "grpc-swift-protobuf")
+      ]
+    )
+  ]
+)

IntegrationTests/PluginTests/test_02_peer_config_file/Sources/Protos/HelloWorld.proto

@@ -0,0 +1,37 @@
+// Copyright 2015, gRPC Authors 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.
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "io.grpc.examples.helloworld";
+option java_outer_classname = "HelloWorldProto";
+option objc_class_prefix = "HLW";
+
+package helloworld;
+
+// The greeting service definition.
+service Greeter {
+  // Sends a greeting
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}

IntegrationTests/PluginTests/test_02_peer_config_file/Sources/Protos/grpc-swift-config.json

@@ -0,0 +1,3 @@
+{
+  "visibility": "internal"
+}

IntegrationTests/PluginTests/test_02_peer_config_file/Sources/adopter.swift

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2024, gRPC Authors 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 GRPCCore
+import GRPCInProcessTransport
+import GRPCProtobuf
+
+@main
+struct PluginAdopter {
+  static func main() async throws {
+    let inProcess = InProcessTransport()
+    try await withGRPCServer(transport: inProcess.server, services: [Greeter()]) { server in
+      try await withGRPCClient(transport: inProcess.client) { client in
+        try await Self.doRPC(Helloworld_Greeter.Client(wrapping: client))
+      }
+    }
+  }
+
+  static func doRPC(_ greeter: Helloworld_Greeter.Client) async throws {
+    do {
+      let reply = try await greeter.sayHello(.with { $0.name = "(ignored)" })
+      print("Reply: \(reply.message)")
+    } catch {
+      print("Error: \(error)")
+    }
+  }
+}
+
+struct Greeter: Helloworld_Greeter.SimpleServiceProtocol {
+  func sayHello(
+    request: Helloworld_HelloRequest,
+    context: ServerContext
+  ) async throws -> Helloworld_HelloReply {
+    return .with { reply in
+      reply.message = "Hello, world!"
+    }
+  }
+}

IntegrationTests/PluginTests/test_03_separate_service_message_protos/.gitignore

@@ -0,0 +1,8 @@
+.DS_Store
+/.build
+/Packages
+xcuserdata/
+DerivedData/
+.swiftpm/configuration/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc

IntegrationTests/PluginTests/test_03_separate_service_message_protos/Package.swift

@@ -0,0 +1,51 @@
+// swift-tools-version: 6.0
+/*
+ * Copyright 2024, gRPC Authors 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 PackageDescription
+
+let package = Package(
+  name: "grpc-adopter",
+  platforms: [
+    .macOS(.v15),
+    .iOS(.v18),
+    .tvOS(.v18),
+    .watchOS(.v11),
+    .visionOS(.v2),
+  ],
+  dependencies: [
+    .package(
+      path: "../../../../grpc-swift-protobuf"
+    ),
+    .package(
+      url: "https://github.com/grpc/grpc-swift.git",
+      exact: "2.0.0-beta.2"
+    ),
+  ],
+  targets: [
+    .executableTarget(
+      name: "grpc-adopter",
+      dependencies: [
+        .product(name: "GRPCCore", package: "grpc-swift"),
+        .product(name: "GRPCInProcessTransport", package: "grpc-swift"),
+        .product(name: "GRPCProtobuf", package: "grpc-swift-protobuf"),
+      ],
+      plugins: [
+        .plugin(name: "GRPCGeneratorPlugin", package: "grpc-swift-protobuf")
+      ]
+    )
+  ]
+)