zones: introduce WireguardConfigWriters

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

pkg/zones/wireguard.go

@@ -10,6 +10,10 @@ var (
 	_ WireguardConfigPruner = (*Zone)(nil)
 	_ WireguardConfigPruner = (*Machine)(nil)
 
+	_ WireguardConfigWriter = (*Zones)(nil)
+	_ WireguardConfigWriter = (*Zone)(nil)
+	_ WireguardConfigWriter = (*Machine)(nil)
+
 	_ WireguardKeysWriter = (*Zones)(nil)
 	_ WireguardKeysWriter = (*Zone)(nil)
 	_ WireguardKeysWriter = (*Machine)(nil)
@@ -60,6 +64,84 @@ func (m *Machine) PruneWireguardConfig(ring int) error {
 	return nil
 }
 
+// A WireguardConfigWriter rewrites all wgN.conf on all machines under
+// its scope attached to that ring
+type WireguardConfigWriter interface {
+	WriteWireguardConfig(ring int) error
+}
+
+// WriteWireguardConfig rewrites all wgN.conf on all machines
+// attached to that ring
+func (m *Zones) WriteWireguardConfig(ring int) error {
+	switch ring {
+	case 0:
+		return writeWireguardConfig(m, m, ring)
+	case 1:
+		var err error
+		m.ForEachZone(func(z *Zone) bool {
+			err = writeWireguardConfig(m, z, ring)
+			return err != nil
+		})
+		return err
+	default:
+		return fs.ErrInvalid
+	}
+}
+
+// WriteWireguardConfig rewrites all wgN.conf on all machines
+// on the Zone attached to that ring
+func (z *Zone) WriteWireguardConfig(ring int) error {
+	switch ring {
+	case 0:
+		return writeWireguardConfig(z.zones, z.zones, ring)
+	case 1:
+		return writeWireguardConfig(z.zones, z, ring)
+	default:
+		return fs.ErrInvalid
+	}
+}
+
+func writeWireguardConfig(z ZoneIterator, m MachineIterator, ring int) error {
+	r, err := NewRing(z, m, ring)
+	if err != nil {
+		return err
+	}
+
+	r.ForEachMachine(func(p *Machine) bool {
+		err = p.writeWireguardRingConfig(r)
+		return err != nil
+	})
+
+	return err
+}
+
+// WriteWireguardConfig rewrites the wgN.conf file of this Machine
+// if enabled
+func (m *Machine) WriteWireguardConfig(ring int) error {
+	r, err := NewRing(m.zone.zones, m.zone, ring)
+	if err != nil {
+		return err
+	}
+
+	return m.writeWireguardRingConfig(r)
+}
+
+func (m *Machine) writeWireguardRingConfig(r *Ring) error {
+	wg, err := r.ExportConfig(m)
+	if err != nil {
+		return nil
+	}
+
+	f, err := m.CreateTruncFile("wg%v.conf", r.ID)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = wg.WriteTo(f)
+	return err
+}
+
 // A WireguardKeysWriter writes the Wireguard Keys for all machines
 // under its scope for the specified ring
 type WireguardKeysWriter interface {