zones: introduce Machine.GetWireguardKeys()

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/machine_rings.go

@@ -10,6 +10,57 @@ import (
 	"git.jpi.io/amery/jpictl/pkg/wireguard"
 )
 
+// GetWireguardKeys reads a wgN.key/wgN.pub files
+func (m *Machine) GetWireguardKeys(ring int) (*wireguard.KeyPair, error) {
+	var (
+		data []byte
+		err  error
+		key  wireguard.PrivateKey
+		pub  wireguard.PublicKey
+	)
+
+	data, err = m.ReadFile("wg%v.key", ring)
+	if err != nil {
+		// failed to read
+		return nil, err
+	}
+
+	key, err = wireguard.PrivateKeyFromBase64(string(data))
+	if err != nil {
+		// bad key
+		err = core.Wrapf(err, "wg%v.key", ring)
+		return nil, err
+	}
+
+	data, err = m.ReadFile("wg%v.pub", ring)
+	switch {
+	case os.IsNotExist(err):
+		// no wgN.pub is fine
+	case err != nil:
+		// failed to read
+		return nil, err
+	default:
+		// good read
+		pub, err = wireguard.PublicKeyFromBase64(string(data))
+		if err != nil {
+			// bad key
+			err = core.Wrapf(err, "wg%v.pub", ring)
+			return nil, err
+		}
+	}
+
+	kp := &wireguard.KeyPair{
+		PrivateKey: key,
+		PublicKey:  pub,
+	}
+
+	if err = kp.Validate(); err != nil {
+		return nil, err
+	}
+
+	return kp, nil
+}
+
 // GetWireguardConfig reads a wgN.conf file
 func (m *Machine) GetWireguardConfig(ring int) (*wireguard.Config, error) {
 	data, err := m.ReadFile("wg%v.conf", ring)