generate gofumpt and go-licenser compliant code

.github/workflows/go.yml

@@ -23,4 +23,18 @@ jobs:
           go-version: '1.21'
 
       - name: Test
-        run: go test ./...
+        run: go test ./...
+
+  test-generator:
+    name: test-generator
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.21'
+
+      - name: Test
+        working-directory: ./internal/generator
+        run: go run .

.github/workflows/lint.yml

@@ -26,6 +26,12 @@ jobs:
         with:
           version: latest
 
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          version: latest
+          working-directory: ./internal/generator
+
   go-mod-tidy:
     name: go-mod-tidy
     runs-on: ubuntu-latest

internal/generator/ecs_flat.go

@@ -114,19 +114,18 @@ func (f *field) isArray() bool {
 			case string:
 				if v == "array" {
 					return true
-				} else {
-					panic(fmt.Errorf("unhandled value for 'normalize' field of %q: %q", f.Name, v))
 				}
+
+				panic(fmt.Errorf("unhandled value for 'normalize' field of %q: %q", f.Name, v))
 			default:
 				panic(fmt.Errorf("unhandled value type for 'normalize' field value type %T in field %q", item, f.Name))
 			}
 		}
 	case string:
 		if v == "array" {
 			return true
-		} else {
-			panic(fmt.Errorf("unhandled value for 'normalize' field of %q: %q", f.Name, v))
 		}
+		panic(fmt.Errorf("unhandled value for 'normalize' field of %q: %q", f.Name, v))
 	case nil:
 	default:
 		panic(fmt.Errorf("unhandled value type for 'normalize' field value type %T in field %q", f.Normalize, f.Name))

internal/generator/generate.go

@@ -35,6 +35,7 @@ import (
 
 	"github.com/coreos/go-semver/semver"
 	"github.com/dave/jennifer/jen"
+	"github.com/elastic/go-licenser/licensing"
 	"github.com/go-git/go-git/v5"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/mitchellh/hashstructure"
@@ -45,8 +46,28 @@ const (
 	appName          = "ecs-generator"
 	remoteRepository = "https://github.com/elastic/ecs"
 	flatFilePath     = "generated/ecs/ecs_flat.yml"
+
+	license  = "ASL2"
+	licensor = "Elasticsearch B.V."
 )
 
+var licenseHeader string
+
+func init() {
+	var sb strings.Builder
+	for _, line := range licensing.Headers[license] {
+		if strings.Contains(line, "%s") {
+			fmt.Fprintf(&sb, line, licensor)
+			sb.WriteByte('\n')
+			continue
+		}
+		sb.WriteString(line)
+		sb.WriteByte('\n')
+	}
+
+	licenseHeader = sb.String()
+}
+
 // Parameters
 var (
 	fetch     bool
@@ -339,6 +360,8 @@ var structListOptions = jen.Options{
 func generateVersionFieldArray(version string, fields []ecsField, w io.Writer) error {
 	f := jen.NewFile("version")
 
+	f.HeaderComment(licenseHeader)
+
 	f.PackageComment("Code generated by generator, DO NOT EDIT.")
 
 	f.Var().Id("v"+strings.ReplaceAll(version, ".", "_")).Op("=").Map(jen.String()).Id("*Field").
@@ -352,20 +375,31 @@ func generateVersionFieldArray(version string, fields []ecsField, w io.Writer) e
 func generateVersionIndex(aliases []versionAlias, w io.Writer) error {
 	f := jen.NewFile("version")
 
+	f.HeaderComment(licenseHeader)
+
 	f.PackageComment("Code generated by generator, DO NOT EDIT.")
 
 	latest := aliases[len(aliases)-1].Version
-	f.Var().Id("Latest").Op("=").Id("v" + strings.ReplaceAll(latest.String(), ".", "_"))
-
-	f.Var().Id("Index").Op("=").Map(jen.String()).Map(jen.String()).Id("*Field").CustomFunc(structListOptions, func(g *jen.Group) {
-		for _, a := range aliases {
-			g.Lit(a.Alias).Op(":").Id("v" + strings.ReplaceAll(a.Version.String(), ".", "_"))
-		}
+	f.Var().DefsFunc(func(g *jen.Group) {
+		// Latest = v1_2_3
+		g.Id("Latest").Op("=").Id(versionIdentifier(latest))
+
+		// Index = map[string]map[string]*Field{ ... }
+		g.Id("Index").Op("=").Map(jen.String()).Map(jen.String()).Id("*Field").
+			CustomFunc(structListOptions, func(g *jen.Group) {
+				for _, a := range aliases {
+					g.Lit(a.Alias).Op(":").Id(versionIdentifier(a.Version))
+				}
+			})
 	})
 
 	return f.Render(w)
 }
 
+func versionIdentifier(v *semver.Version) string {
+	return "v" + strings.ReplaceAll(v.String(), ".", "_")
+}
+
 func fieldsDefs(fields []ecsField, g *jen.Group) {
 	for _, f := range fields {
 		values := []jen.Code{

internal/generator/go.mod

@@ -5,6 +5,7 @@ go 1.21
 require (
 	github.com/coreos/go-semver v0.3.1
 	github.com/dave/jennifer v1.7.0
+	github.com/elastic/go-licenser v0.4.2-0.20230608174114-6eca7dbbc006
 	github.com/go-git/go-git/v5 v5.9.0
 	github.com/mitchellh/hashstructure v1.1.0
 	gopkg.in/yaml.v3 v3.0.1

internal/generator/go.sum

@@ -23,6 +23,8 @@ github.com/dave/jennifer v1.7.0/go.mod h1:nXbxhEmQfOZhWml3D1cDK5M1FLnMSozpbFN/m3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/elastic/go-licenser v0.4.2-0.20230608174114-6eca7dbbc006 h1:anF5YCbLmZOEXpE/2pwG1F0Jdy6s8tfKef4dKri4bkk=
+github.com/elastic/go-licenser v0.4.2-0.20230608174114-6eca7dbbc006/go.mod h1:W8eH6FaZDR8fQGm+7FnVa7MxI1b/6dAqxz+zPB8nm5c=
 github.com/elazarl/goproxy v0.0.0-20230808193330-2592e75ae04a h1:mATvB/9r/3gvcejNsXKSkQ6lcIaNec2nyfOdlTBR2lU=
 github.com/elazarl/goproxy v0.0.0-20230808193330-2592e75ae04a/go.mod h1:Ro8st/ElPeALwNFlcTpWmkr6IoMFfkjXAvTHpevnDsM=
 github.com/emirpasic/gods v1.18.1 h1:FXtiHYKDGKCW2KzwZKx0iC0PQmdlorYgdFG9jPXJ1Bc=