mdtogo: support for alternate license headers

cmd/config/.golangci.yml

@@ -12,7 +12,7 @@ linters:
     - bodyclose
     - deadcode
     - depguard
-    - dogsled
+#    - dogsled
     - dupl
 #    - errcheck
 #    - funlen

cmd/config/main.go

@@ -1,8 +1,8 @@
 // Copyright 2019 The Kubernetes Authors.
 // SPDX-License-Identifier: Apache-2.0
 
-//go:generate $GOBIN/mdtogo docs/api-conventions cmddocs/api --full=true
-//go:generate $GOBIN/mdtogo docs/commands cmddocs/commands
+//go:generate $GOBIN/mdtogo docs/api-conventions cmddocs/api --full=true --license=none
+//go:generate $GOBIN/mdtogo docs/commands cmddocs/commands --license=none
 package main
 
 import (

cmd/mdtogo/main.go

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 // Package main generates cobra.Command go variables containing documentation read from .md files.
-// Usage: mdtogo SOURCE_MD_DIR/ DEST_GO_DIR/ [--full=true]
+// Usage: mdtogo SOURCE_MD_DIR/ DEST_GO_DIR/ [--full=true] [--license=license.txt|none]
 //
 // The command will create a docs.go file under DEST_GO_DIR/ containing string variables to be
 // used by cobra commands for documentation.The variable names are generated from the SOURCE_MD_DIR/
@@ -28,6 +28,13 @@
 //   ## cmd
 //
 //   All sections will be parsed into a Long string.
+//
+// Flags:
+//   --full=true
+//     Create a Long variable from the full .md files, rather than separate sections.
+//   --license
+//     Controls the license header added to the files.  Specify a path to a license file,
+//     or "none" to skip adding a license.
 package main
 
 import (
@@ -42,12 +49,16 @@ import (
 )
 
 var full bool
+var licenseFile string
 
 func main() {
 	for _, a := range os.Args {
 		if a == "--full=true" {
 			full = true
 		}
+		if strings.HasPrefix(a, "--license=") {
+			licenseFile = strings.ReplaceAll(a, "--license=", "")
+		}
 	}
 
 	if len(os.Args) < 3 {
@@ -77,9 +88,23 @@ func main() {
 		docs = append(docs, parse(f.Name(), string(b)))
 	}
 
-	out := []string{`// Copyright 2019 The Kubernetes Authors.
-// SPDX-License-Identifier: Apache-2.0
+	var license string
 
+	if licenseFile == "" {
+		license = `// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0`
+	} else if licenseFile == "none" {
+		// no license -- maybe added by another tool
+	} else {
+		b, err := ioutil.ReadFile(licenseFile)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%v\n", err)
+			os.Exit(1)
+		}
+		license = string(b)
+	}
+
+	out := []string{license, `
 // Code generated by "mdtogo"; DO NOT EDIT.
 package ` + filepath.Base(dest) + "\n"}