feat: add cli first class validation

Emyrk · Emyrk · commit 9572e9073e6b · 2023-07-07T10:37:13.000-04:00
diff --git a/cli/clibase/values.go b/cli/clibase/values.go
@@ -16,6 +16,59 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+// Validator is a wrapper around a pflag.Value that allows for validation
+// of the value after or before it has been set.
+type Validator[T pflag.Value] struct {
+	Value T
+	// ValidateBefore is called before the value is set.
+	ValidateBefore func(input string) error
+	// ValidateAfter is called after the value is set.
+	ValidateAfter func(T) error
+}
+
+func Validate[T pflag.Value](opt T) *Validator[T] {
+	return &Validator[T]{Value: opt}
+}
+
+func (i *Validator[T]) Before(fn func(input string) error) *Validator[T] {
+	i.ValidateBefore = fn
+	return i
+}
+
+func (i *Validator[T]) After(fn func(value T) error) *Validator[T] {
+	i.ValidateAfter = fn
+	return i
+}
+
+func (i *Validator[T]) String() string {
+	return i.Value.String()
+}
+
+func (i *Validator[T]) Set(input string) error {
+	if i.ValidateBefore != nil {
+		err := i.ValidateBefore(input)
+		if err != nil {
+			return err
+		}
+	}
+
+	err := i.Value.Set(input)
+	if err != nil {
+		return err
+	}
+	if i.ValidateAfter != nil {
+		err = i.ValidateAfter(i.Value)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (i *Validator[T]) Type() string {
+	return i.Value.Type()
+}
+
 // NoOptDefValuer describes behavior when no
 // option is passed into the flag.
 //
diff --git a/enterprise/cli/workspaceproxy.go b/enterprise/cli/workspaceproxy.go
@@ -235,6 +235,12 @@ func (r *RootCmd) createProxy() *clibase.Cmd {
 		noPrompts   bool
 		formatter   = newUpdateProxyResponseFormatter()
 	)
+	validateIcon := func(s string) error {
+		if !(strings.HasPrefix(s, "/emojis/") || strings.HasPrefix(s, "http")) {
+			return xerrors.New("icon must be a relative path to an emoji or a publicly hosted image URL")
+		}
+		return nil
+	}
 
 	client := new(codersdk.Client)
 	cmd := &clibase.Cmd{
@@ -268,14 +274,9 @@ func (r *RootCmd) createProxy() *clibase.Cmd {
 
 			if proxyIcon == "" && !noPrompts {
 				proxyIcon, err = cliui.Prompt(inv, cliui.PromptOptions{
-					Text:    "Icon URL:",
-					Default: "/emojis/1f5fa.png",
-					Validate: func(s string) error {
-						if !(strings.HasPrefix(s, "/emojis/") || strings.HasPrefix(s, "http")) {
-							return xerrors.New("icon must be a relative path to an emoji or a publicly hosted image URL")
-						}
-						return nil
-					},
+					Text:     "Icon URL:",
+					Default:  "/emojis/1f5fa.png",
+					Validate: validateIcon,
 				})
 				if err != nil {
 					return err
@@ -319,7 +320,7 @@ func (r *RootCmd) createProxy() *clibase.Cmd {
 		clibase.Option{
 			Flag:        "icon",
 			Description: "Display icon of the proxy.",
-			Value:       clibase.StringOf(&proxyIcon),
+			Value:       clibase.Validate(clibase.StringOf(&proxyIcon)).Before(validateIcon),
 		},
 		clibase.Option{
 			Flag:        "no-prompt",
