1 files changed, 65 insertions, 0 deletions
diff --git a/internal/options/options.go b/internal/options/options.go
new file mode 100644
index 0000000..8e4ab0c
--- /dev/null
+++ b/internal/options/options.go
@@ -0,0 +1,65 @@
+package options
+
+import (
+	"flag"
+	"fmt"
+)
+
+const (
+	DefaultString = "default string"
+	DefaultUint64 = 18446744073709551615
+)
+
+// New initializes a flag set using the provided arguments.
+//
+//   - args should start with the (sub)command's name
+//   - usage is a function that prints a usage message
+//   - set is a function that sets the command's flag arguments
+//
+func New(args []string, usage func(), set func(*flag.FlagSet)) *flag.FlagSet {
+	if len(args) == 0 {
+		args = append(args, "")
+	}
+
+	fs := flag.NewFlagSet(args[0], flag.ExitOnError)
+	fs.Usage = func() {
+		usage()
+	}
+	set(fs)
+	fs.Parse(args[1:])
+	return fs
+}
+
+// AddString adds a string option to a flag set
+func AddString(fs *flag.FlagSet, opt *string, short, long, value string) {
+	fs.StringVar(opt, short, value, "")
+	fs.StringVar(opt, long, value, "")
+}
+
+// AddUint64 adds an uint64 option to a flag set
+func AddUint64(fs *flag.FlagSet, opt *uint64, short, long string, value uint64) {
+	fs.Uint64Var(opt, short, value, "")
+	fs.Uint64Var(opt, long, value, "")
+}
+
+// CheckString checks that a string option has a non-default value
+func CheckString(optionName, value string, err error) error {
+	if err != nil {
+		return err
+	}
+	if value == DefaultString {
+		return fmt.Errorf("%s is a required option", optionName)
+	}
+	return nil
+}
+
+// CheckUint64 checks that an uint64 option has a non-default value
+func CheckUint64(optionName string, value uint64, err error) error {
+	if err != nil {
+		return err
+	}
+	if value == DefaultUint64 {
+		return fmt.Errorf("%s is a required option", optionName)
+	}
+	return nil
+}