construct wgctrl client in setup()

setup.go

@@ -1,9 +1,12 @@
 package wgsd
 
 import (
+	"fmt"
+
 	"github.com/caddyserver/caddy"
 	"github.com/coredns/coredns/core/dnsserver"
 	"github.com/coredns/coredns/plugin"
+	"golang.zx2c4.com/wireguard/wgctrl"
 )
 
 func init() {
@@ -11,9 +14,20 @@ func init() {
 }
 
 func setup(c *caddy.Controller) error {
+	client, err := wgctrl.New()
+	if err != nil {
+		return fmt.Errorf("wgsd: error constructing wgctrl client: %v",
+			err)
+	}
+
+	// TODO: parse zone and wireguard device name from config
+
 	// Add the Plugin to CoreDNS, so Servers can use it in their plugin chain.
 	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
-		return &WGSD{Next: next}
+		return &WGSD{
+			Next:   next,
+			client: client,
+		}
 	})
 
 	return nil