adding define/block-support across different sources

.gitignore

@@ -1 +1,2 @@
-bin/
+bin/
+test/

Makefile

@@ -29,3 +29,6 @@ m-j:
 
 multi:
 	go run . -i test/m-input.yaml -i test/m-input.json test/m-tmpl.yaml -v -s
+
+adv:
+	go run . -i test/advanced/input.yaml test/advanced/*.tmpl8 -v

README.md

@@ -11,16 +11,20 @@ Generic (and Kubernetes-friendly) Templating Engine using the go text/template a
 Supported input formats: JSON and YAML
 
 ```
-tmpl8 [--input INPUT] [--output FILE] [--verbose] [--raw] [--split] TEMPLATE [TEMPLATE ...]
+tmpl8 [--input INPUT] [--output FILE] [--verbose] [--trace] [--raw] [--split] [--noinput] TEMPLATE [TEMPLATE ...]
 ```
 
 ### Options
-| Option            | Description |
-| ----------------- | ----------- |
-| `-i` / `--input`  | Manual assign where to read input object(s) from, use '`-`' to use stdin, multiple inputs supported |
-| `-o` / `--output` | Set output filename (instead of using `>`)             |
-| `-r` / `--raw`    | Don't ensure each template ends with a newline (not recommended for YAML output)|
-| `-s` / `--split`  | Split JSON input objects arrays to multiple objects parsed each (similar to YAMLs with `---` separators) |
+| Option             | Description |
+| -----------------  | ----------- |
+| `-i` / `--input`   | Manual assign where to read input object(s) from, use '`-`' to use stdin, multiple inputs supported |
+| `-z` / `--noinput` | Add an empty object as input (for template-only processing) |
+| `-o` / `--output`  | Set output filename (instead of using `>`)             |
+| `-r` / `--raw`     | Don't ensure each template ends with a newline (not recommended for YAML output)|
+| `-s` / `--split`   | Split JSON input objects arrays to multiple objects parsed each (similar to YAMLs with `---` separators) |
+
+## define/block support
+Any `define`/`block` helpers are useable in templates in all following template sources (and can be overridden)
 
 ## Examples
 

args.go

@@ -8,12 +8,14 @@ import (
 )
 
 type arguments struct {
-	Inputs    []string `arg:"-i,--input,separate" help:"filename of objects to import and process (use '-' for stdin)"`
-	Templates []string `arg:"required,positional" help:"filename.tmpl | @filenames.lst | k8s:namespace/configmap" placeholder:"TEMPLATE"`
-	Output    string   `arg:"-o,--output" help:"destination filename" placeholder:"FILE"`
-	Verbose   bool     `arg:"-v,--verbose" help:"verbose output"`
-	Raw       bool     `arg:"-r,--raw" help:"will NOT ensure newline and end of each block"`
-	Split     bool     `arg:"-s,--split" help:"split json-array into separate 'documents'"`
+	Inputs      []string `arg:"-i,--input,separate" help:"filename of objects to import and process (use '-' for stdin)"`
+	Templates   []string `arg:"required,positional" help:"filename.tmpl | @filenames.lst | k8s:namespace/configmap" placeholder:"TEMPLATE"`
+	Output      string   `arg:"-o,--output" help:"destination filename" placeholder:"FILE"`
+	Verbose     bool     `arg:"-v,--verbose" help:"verbose output"`
+	VeryVerbose bool     `arg:"-t,--trace" help:"trace output"`
+	Raw         bool     `arg:"-r,--raw" help:"will NOT ensure newline and end of each block"`
+	Split       bool     `arg:"-s,--split" help:"split json-array into separate 'documents'"`
+	NoInput     bool     `arg:"-z" help:"no input (equals -i '?{}')"`
 }
 
 func (arguments) Description() string {
@@ -38,6 +40,14 @@ func init() {
 		os.Exit(1)
 	}
 
+	if args.NoInput {
+		args.Inputs = append(args.Inputs, "?{}")
+	}
+
+	if args.VeryVerbose {
+		args.Verbose = true
+	}
+
 	if len(args.Inputs) == 0 {
 		args.Inputs = append(args.Inputs, "-")
 	}

main.go

@@ -37,8 +37,14 @@ func main() {
 		log.Info().Msgf("generating %d objects using %d templates", len(olist), len(templates))
 	}
 
+	t, err := prepare(templates)
+	if err != nil {
+		log.Error().Msgf("prepare-template-error: %v", err)
+		os.Exit(1)
+	}
+
 	for _, o := range olist {
-		err = handle(templates, o, &output)
+		err = process(t, o, &output)
 		if err != nil {
 			log.Error().Msgf("template-error: %v", err)
 			os.Exit(1)
@@ -59,24 +65,35 @@ func main() {
 
 }
 
-func handle(list []entry, o interface{}, w io.Writer) error {
-	// list, err := load(fn)
-	// if err != nil {
-	// 	return err
-	// }
+func prepare(list []entry) ([]*template.Template, error) {
+	if args.VeryVerbose {
+		log.Trace().Msgf("preparing %d template", len(list))
+	}
+	var tmpls []*template.Template
+
+	tmpl := template.New("base").Funcs(sprig.TxtFuncMap())
+	var err error
 
 	for _, e := range list {
-		if args.Verbose {
-			log.Trace().Msgf("applying template '%s'...", e.name)
+		if args.VeryVerbose {
+			log.Trace().Msgf("parsing template '%s'...", e.name)
 		}
-
-		tmpl, err := template.New("base").Funcs(sprig.TxtFuncMap()).Parse(e.data)
+		tmpl, err = tmpl.New(e.name).Parse(e.data)
 		if err != nil {
-			return err
+			return nil, err
 		}
+		tmpls = append(tmpls, tmpl)
+	}
+	return tmpls, nil
+}
 
+func process(tmpls []*template.Template, o interface{}, w io.Writer) error {
+	for _, tmpl := range tmpls {
+		if args.VeryVerbose {
+			log.Trace().Msgf("executing template '%s'...", tmpl.Name())
+		}
 		var buf bytes.Buffer
-		err = tmpl.Execute(&buf, o)
+		err := tmpl.Execute(&buf, o)
 		if err != nil {
 			return err
 		}