Add method to write out the file

Signed-off-by: kolaente <k@knt.li>

magefile.go

@@ -746,6 +746,8 @@ func parseYamlConfigNode(node *yaml.Node) (config *configOption) {
 		description: strings.ReplaceAll(node.HeadComment, "# ", ""),
 	}
 
+	// TODO: second-level comments don't work
+
 	for i, n2 := range node.Content {
 		coo := &configOption{
 			key:         n2.Value,
@@ -777,6 +779,7 @@ func printConfig(config []*configOption, level int) (rendered string) {
 	for _, option := range config {
 		if option.key != "" {
 
+			rendered += "#"
 			for i := 0; i <= level; i++ {
 				rendered += "#"
 			}
@@ -802,6 +805,11 @@ func printConfig(config []*configOption, level int) (rendered string) {
 	return
 }
 
+const (
+	configDocPath       = `docs/content/doc/setup/config.md`
+	configInjectComment = `<!-- Generated config will be injected here -->`
+)
+
 // Generates the error docs from a commented config.yml.sample file in the repo root.
 func GenerateDocs() error {
 
@@ -825,7 +833,37 @@ func GenerateDocs() error {
 		}
 	}
 
-	fmt.Println(printConfig(conf, 0))
+	renderedConfig := printConfig(conf, 0)
+
+	// Rebuild the config
+	file, err := os.OpenFile(configDocPath, os.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	// We read the config doc up until the marker, then stop and append our generated config
+	fullConfig := ""
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		t := scanner.Text()
+		fullConfig += t + "\n"
+
+		if t == configInjectComment {
+			break
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+
+	fullConfig += "\n" + renderedConfig
+
+	if _, err := file.WriteAt([]byte(fullConfig), 0); err != nil {
+		return err
+	}
 
 	return nil
 }