Migrate CI to use swiftlang / SwiftNIO common GitHub Actions. (#2105)

### Motivation:

* Reduce duplication
* Centralise boilerplate changes when new Swift versions are picked up.
* Benefit from centralised work to add new linting / test
infrastructure.

### Modifications:

Changes of note:
* Use soundness checks from swiftlang/github-workflows.
* Define a gRPC-specific soundness check which retains bespoke
license-checking code for .swift files as the gRPC header style is very
different to most templates and checks that generated code is
up-to-date.

### Result:

More test, linting, formatting coverage. More common CI with other Swift
on Server projects.

.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 +1,26 @@
+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_enabled: false
+      linux_5_10_enabled: false
+      linux_6_0_arguments_override: "--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"
+
+  benchmarks:
+    name: Benchmarks
+    uses: apple/swift-nio/.github/workflows/benchmarks.yml@main
+    with:
+      benchmark_package_path: "IntegrationTests/Benchmarks"
+      linux_5_9_enabled: false
+      linux_5_10_enabled: false

.github/workflows/pull_request.yml

@@ -0,0 +1,51 @@
+name: PR
+
+on:
+  pull_request:
+    branches: [main]
+    types: [opened, reopened, synchronize]
+
+jobs:
+  soundness:
+    name: Soundness
+    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+    with:
+      license_header_check_project_name: "gRPC"
+
+  grpc-soundness:
+    name: Soundness
+    uses: ./.github/workflows/soundness.yml
+
+  unit-tests:
+    name: Unit tests
+    uses: apple/swift-nio/.github/workflows/unit_tests.yml@main
+    with:
+      linux_5_9_enabled: false
+      linux_5_10_enabled: false
+      linux_6_0_arguments_override: "--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"
+
+  examples:
+    name: Examples
+    uses: apple/swift-nio/.github/workflows/swift_matrix.yml@main
+    with:
+      name: "Examples"
+      matrix_linux_5_9_enabled: false
+      matrix_linux_5_10_enabled: false
+      matrix_linux_command: "./dev/build-examples.sh"
+
+  benchmarks:
+    name: Benchmarks
+    uses: apple/swift-nio/.github/workflows/benchmarks.yml@main
+    with:
+      benchmark_package_path: "IntegrationTests/Benchmarks"
+      linux_5_9_enabled: false
+      linux_5_10_enabled: false
+
+  cxx-interop:
+    name: Cxx interop
+    uses: apple/swift-nio/.github/workflows/cxx_interop.yml@main
+    with:
+      linux_5_9_enabled: false
+      linux_5_10_enabled: false

.github/workflows/pull_request_label.yml

@@ -0,0 +1,18 @@
+name: PR
+
+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

.github/workflows/soundness.yml

@@ -0,0 +1,37 @@
+name: Soundness
+
+on:
+  workflow_call:
+
+jobs:
+  swift-license-check:
+    name: Swift license headers check
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Mark the workspace as safe
+        run: git config --global --add safe.directory ${GITHUB_WORKSPACE}
+      - name: Run license check
+        run: |
+          ./dev/license-check.sh
+
+  check-generated-code:
+    name: Check generated code
+    runs-on: ubuntu-latest
+    container:
+      image: swift:latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Mark the workspace as safe
+        run: git config --global --add safe.directory ${GITHUB_WORKSPACE}
+      - name: Install protoc
+        run: apt update && apt install -y protobuf-compiler
+      - name: Run soundness checks
+        run: |
+          ./dev/check-generated-code.sh

.license_header_template

@@ -0,0 +1,13 @@
+@@ Copyright YEARS, 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.

.licenseignore

@@ -0,0 +1,42 @@
+.gitignore
+**/.gitignore
+.licenseignore
+.gitattributes
+.git-blame-ignore-revs
+.gitmodules
+.mailfilter
+.mailmap
+.spi.yml
+.swift-format
+.editorconfig
+.github/*
+*.md
+*.txt
+*.yml
+*.yaml
+*.json
+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
+dev/version-bump.commit.template
+.unacceptablelanguageignore
+.swiftformatignore
+LICENSE
+**/*.swift
+dev/protos/**/*.proto
+Examples/hello-world/Protos/HelloWorld.proto

.swiftformatignore

@@ -0,0 +1,2 @@
+*.grpc.swift
+*.pb.swift

.unacceptablelanguageignore

@@ -0,0 +1,3 @@
+**/*.pb.swift
+**/*.grpc.swift
+dev/protos/upstream/**/*.proto

CONTRIBUTING.md

@@ -17,3 +17,7 @@ In order to protect both you and ourselves, you will need to sign the
 
 Please see the [main gRPC repository](https://github.com/grpc/grpc) for
 more information about gRPC.
+
+### Run CI checks locally
+
+You can run the GitHub Actions workflows locally using [act](https://github.com/nektos/act) or in some cases calling scripts directly. For detailed steps on how to do this please see [https://github.com/swiftlang/github-workflows?tab=readme-ov-file#running-workflows-locally](https://github.com/swiftlang/github-workflows?tab=readme-ov-file#running-workflows-locally).

Examples/hello-world/Protos/HelloWorld.proto

@@ -0,0 +1 @@
+../../..//dev/protos/upstream/grpc/examples/helloworld.proto

IntegrationTests/Benchmarks/Package.swift

@@ -17,25 +17,25 @@
 import PackageDescription
 
 let package = Package(
-    name: "benchmarks",
-    platforms: [
-        .macOS(.v13),
-    ],
-    dependencies: [
-        .package(path: "../../"),
-        .package(url: "https://github.com/ordo-one/package-benchmark", from: "1.11.2")
-    ],
-    targets: [
-        .executableTarget(
-            name: "GRPCSwiftBenchmark",
-            dependencies: [
-                .product(name: "Benchmark", package: "package-benchmark"),
-                .product(name: "GRPCCore", package: "grpc-swift")
-            ],
-            path: "Benchmarks/GRPCSwiftBenchmark",
-            plugins: [
-                .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
-            ]
-        ),
-    ]
+  name: "benchmarks",
+  platforms: [
+    .macOS(.v13)
+  ],
+  dependencies: [
+    .package(path: "../../"),
+    .package(url: "https://github.com/ordo-one/package-benchmark", from: "1.11.2"),
+  ],
+  targets: [
+    .executableTarget(
+      name: "GRPCSwiftBenchmark",
+      dependencies: [
+        .product(name: "Benchmark", package: "package-benchmark"),
+        .product(name: "GRPCCore", package: "grpc-swift"),
+      ],
+      path: "Benchmarks/GRPCSwiftBenchmark",
+      plugins: [
+        .plugin(name: "BenchmarkPlugin", package: "package-benchmark")
+      ]
+    )
+  ]
 )