etcd: Rewrite embed etcd implementation

This is a giant cleanup of the etcd code. The earlier version was
written when I was less experienced with golang.

This is still not perfect, and does contain some races, but at least
it's a decent base to start from. The automatic elastic clustering
should be considered an experimental feature. If you need a more
battle-tested cluster, then you should manage etcd manually and point
mgmt at your existing cluster.

etcd/etcd_test.go

@@ -21,31 +21,19 @@ package etcd
 
 import (
 	"testing"
-
-	etcdtypes "github.com/coreos/etcd/pkg/types"
 )
 
-func TestNewEmbdEtcd(t *testing.T) {
-	// should return a new etcd object
-
-	noServer := false
-	var flags Flags
-
-	obj := NewEmbdEtcd("", nil, nil, nil, nil, nil, noServer, false, 0, flags, "", nil)
-	if obj == nil {
-		t.Fatal("failed to create server object")
-	}
-}
-
-func TestNewEmbdEtcdConfigValidation(t *testing.T) {
-	// running --no-server with no --seeds specified should fail early
-
-	seeds := make(etcdtypes.URLs, 0)
-	noServer := true
-	var flags Flags
-
-	obj := NewEmbdEtcd("", seeds, nil, nil, nil, nil, noServer, false, 0, flags, "", nil)
-	if obj != nil {
-		t.Fatal("server initialization should fail on invalid configuration")
+func TestValidation1(t *testing.T) {
+	// running --no-server with no --seeds should not validate at the moment
+	embdEtcd := &EmbdEtcd{
+		//Seeds: etcdtypes.URLs{},
+		NoServer: true,
+	}
+	if err := embdEtcd.Validate(); err == nil {
+		t.Errorf("expected validation err, got nil")
+	}
+	if err := embdEtcd.Init(); err == nil {
+		t.Errorf("expected init err, got nil")
+		defer embdEtcd.Close()
 	}
 }