Refactor client I/O into protocol package

client/processing/process.go

@@ -0,0 +1,20 @@
+package processing
+
+import (
+	"fmt"
+	"git.cacert.org/cacert-gosigner/datastructures"
+	"github.com/sirupsen/logrus"
+)
+
+func Process(response *datastructures.SignerResponse) (err error) {
+	logrus.Infof("process response of type %s", response.Action)
+	logrus.Tracef("process response %v", response)
+
+	switch response.Action {
+	case datastructures.ActionNul:
+		logrus.Trace("received response for NUL request")
+		return
+	default:
+		return fmt.Errorf("unsupported action in response 0x%x", response.Action)
+	}
+}