templates: if a default init/uinit/shell is specified, allow template…

…s to override with empty

Signed-off-by: Chris Koch <[email protected]>

uimage/templates/templates.go

@@ -52,9 +52,9 @@ type Config struct {
 	BuildTags []string `yaml:"build_tags"`
 	Commands  []Command
 	Files     []string
-	Init      string
-	Uinit     string
-	Shell     string
+	Init      *string
+	Uinit     *string
+	Shell     *string
 }
 
 // Templates are a set of mkuimage build configs and command templates.
@@ -79,15 +79,21 @@ func (t *Templates) Uimage(config string) ([]uimage.Modifier, error) {
 	}
 	m := []uimage.Modifier{
 		uimage.WithFiles(c.Files...),
-		uimage.WithInit(c.Init),
-		uimage.WithUinitCommand(c.Uinit),
-		uimage.WithShell(c.Shell),
 		uimage.WithEnv(
 			golang.WithGOOS(c.GOOS),
 			golang.WithGOARCH(c.GOARCH),
 			golang.WithBuildTag(c.BuildTags...),
 		),
 	}
+	if c.Init != nil {
+		m = append(m, uimage.WithInit(*c.Init))
+	}
+	if c.Uinit != nil {
+		m = append(m, uimage.WithUinitCommand(*c.Uinit))
+	}
+	if c.Shell != nil {
+		m = append(m, uimage.WithShell(*c.Shell))
+	}
 	for _, cmds := range c.Commands {
 		switch cmds.Builder {
 		case "binary":

uimage/templates/templates_test.go

@@ -21,6 +21,7 @@ func TestMods(t *testing.T) {
 		name   string
 		tpl    string
 		config string
+		base   []uimage.Modifier
 		want   *uimage.Opts
 		err    error
 	}{
@@ -109,6 +110,21 @@ configs:
 `,
 			config: "",
 		},
+		{
+			name: "override base",
+			tpl: `
+configs:
+  noinit:
+    init: ""
+`,
+			config: "noinit",
+			base: []uimage.Modifier{
+				uimage.WithInit("init"),
+			},
+			want: &uimage.Opts{
+				Env: golang.Default(),
+			},
+		},
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			tpl, err := TemplateFrom([]byte(tt.tpl))
@@ -122,7 +138,7 @@ configs:
 			if len(mods) == 0 {
 				return
 			}
-			got, err := uimage.OptionsFor(mods...)
+			got, err := uimage.OptionsFor(append(tt.base, mods...)...)
 			if err != nil {
 				t.Fatal(err)
 			}

uimage/uimage.go

@@ -559,9 +559,6 @@ func WithUinit(arg0 string, args ...string) Modifier {
 // This can be an absolute path or the name of a command included in
 // Commands.
 func WithInit(arg0 string) Modifier {
-	if arg0 == "" {
-		return nil
-	}
 	return func(opts *Opts) error {
 		opts.InitCmd = arg0
 		return nil
@@ -574,9 +571,6 @@ func WithInit(arg0 string) Modifier {
 // This can be an absolute path or the name of a command included in
 // Commands.
 func WithShell(arg0 string) Modifier {
-	if arg0 == "" {
-		return nil
-	}
 	return func(opts *Opts) error {
 		opts.DefaultShell = arg0
 		return nil
@@ -585,9 +579,6 @@ func WithShell(arg0 string) Modifier {
 
 // WithTempDir sets a temporary directory to use for building commands.
 func WithTempDir(dir string) Modifier {
-	if dir == "" {
-		return nil
-	}
 	return func(o *Opts) error {
 		o.TempDir = dir
 		return nil