add uncloud machine token command to print machine token to add machine to cluster

internal/machine/token.go

@@ -0,0 +1,54 @@
+package machine
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/netip"
+	"strings"
+	"uncloud/internal/secret"
+)
+
+const (
+	TokenPrefix = "mtkn:"
+)
+
+// Token represents the machine's token for joining a cluster.
+type Token struct {
+	PublicKey secret.Secret
+	Endpoints []netip.AddrPort
+}
+
+// NewToken creates a new machine token with the given public key and endpoints.
+func NewToken(publicKey secret.Secret, endpoints []netip.AddrPort) Token {
+	return Token{
+		PublicKey: publicKey,
+		Endpoints: endpoints,
+	}
+}
+
+// ParseToken decodes a machine token from the given string.
+func ParseToken(s string) (Token, error) {
+	if strings.HasPrefix(s, TokenPrefix) {
+		return Token{}, fmt.Errorf("invalid token prefix")
+	}
+	decoded, err := base64.StdEncoding.DecodeString(s[len(TokenPrefix):])
+	if err != nil {
+		return Token{}, fmt.Errorf("decode token: %w", err)
+	}
+	var token Token
+	if err = json.Unmarshal(decoded, &token); err != nil {
+		return Token{}, fmt.Errorf("unmarshal token: %w", err)
+	}
+	return token, nil
+}
+
+// String returns the machine token encoded as a string.
+func (t Token) String() (string, error) {
+	js, err := json.Marshal(t)
+	if err != nil {
+		return "", fmt.Errorf("marshal token: %w", err)
+	}
+	encoded := base64.StdEncoding.EncodeToString(js)
+	return TokenPrefix + encoded, nil
+}