ci: add initial builds for Go development

Initiate github.com/googleapis/generator as a Go module, and introduce
the initial CI builds to support Go development.

.github/workflows/generator.yaml

@@ -0,0 +1,33 @@
+# Copyright 2024 Google LLC
+#
+# 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
+#
+#     https://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.
+
+name: Generator
+on: [push, pull_request]
+permissions:
+  contents: read
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with:
+        go-version-file: 'go.mod'
+    - name: Display Go version
+      run: go version
+    - name: Run tests
+      run: go test ./...
+    - run: go fmt ./...
+    - name: Detect Changes
+      run: git diff --exit-code

all_test.go

@@ -0,0 +1,86 @@
+// Copyright 2024 Google LLC
+//
+// 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
+//
+//     https://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.
+
+package main_test
+
+import (
+	"bufio"
+	"errors"
+	"io/fs"
+	"os"
+	"os/exec"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+var googleHeader = regexp.MustCompile(`^// Copyright 20\d\d Google LLC
+//
+// Licensed under the Apache License, Version 2\.0 \(the "License"\);`)
+
+func TestHeaders(t *testing.T) {
+	sfs := os.DirFS(".")
+	fs.WalkDir(sfs, ".", func(path string, d fs.DirEntry, _ error) error {
+		if d.IsDir() {
+			if d.Name() == "testdata" {
+				return fs.SkipDir
+			}
+			return nil
+		}
+		if !strings.HasSuffix(path, ".go") {
+			return nil
+		}
+		f, err := sfs.Open(path)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		if !googleHeader.MatchReader(bufio.NewReader(f)) {
+			t.Errorf("%q: incorrect header", path)
+		}
+		return nil
+	})
+}
+
+func TestStaticCheck(t *testing.T) {
+	rungo(t, "run", "honnef.co/go/tools/cmd/[email protected]", "./...")
+}
+
+func TestUnparam(t *testing.T) {
+	rungo(t, "run", "mvdan.cc/[email protected]", "./...")
+}
+
+func TestVet(t *testing.T) {
+	rungo(t, "vet", "-all", "./...")
+}
+
+func TestGoModTidy(t *testing.T) {
+	rungo(t, "mod", "tidy", "-diff")
+}
+
+func TestGovulncheck(t *testing.T) {
+	rungo(t, "run", "golang.org/x/vuln/cmd/[email protected]", "./...")
+}
+
+func rungo(t *testing.T, args ...string) {
+	t.Helper()
+
+	cmd := exec.Command("go", args...)
+	if output, err := cmd.CombinedOutput(); err != nil {
+		if ee := (*exec.ExitError)(nil); errors.As(err, &ee) && len(ee.Stderr) > 0 {
+			t.Fatalf("%v: %v\n%s", cmd, err, ee.Stderr)
+		}
+		t.Fatalf("%v: %v\n%s", cmd, err, output)
+	}
+}

cmd/generator/main.go

@@ -0,0 +1,21 @@
+// Copyright 2024 Google LLC
+//
+// 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
+//
+//     https://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.
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("TODO: implement generator")
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/googleapis/generator
+
+go 1.23.0