1 files changed, 46 insertions, 0 deletions
diff --git a/cmd/podman/validate/choice.go b/cmd/podman/validate/choice.go
new file mode 100644
index 000000000..572c5f4a5
--- /dev/null
+++ b/cmd/podman/validate/choice.go
@@ -0,0 +1,46 @@
+package validate
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Honors cobra.Value interface
+type choiceValue struct {
+	value   *string
+	choices []string
+}
+
+// ChoiceValue may be used in cobra FlagSet methods Var/VarP/VarPF() to select from a set of values
+//
+// Example:
+// 	created := validate.ChoiceValue(&opts.Sort, "command", "created", "id", "image", "names", "runningfor", "size", "status")
+//	flags.Var(created, "sort", "Sort output by: "+created.Choices())
+func ChoiceValue(p *string, choices ...string) *choiceValue {
+	return &choiceValue{
+		value:   p,
+		choices: choices,
+	}
+}
+
+func (c *choiceValue) String() string {
+	return *c.value
+}
+
+func (c *choiceValue) Set(value string) error {
+	for _, v := range c.choices {
+		if v == value {
+			*c.value = value
+			return nil
+		}
+	}
+	return fmt.Errorf("%q is not a valid value.  Choose from: %q", value, c.Choices())
+}
+
+func (c *choiceValue) Choices() string {
+	return strings.Join(c.choices, ", ")
+}
+
+func (c *choiceValue) Type() string {
+	return "choice"
+}