Protect against double-close of NodeTransport

store/transport.go

@@ -51,7 +51,8 @@ func (t *Transport) Addr() net.Addr {
 // custom configuration of the InstallSnapshot method.
 type NodeTransport struct {
 	*raft.NetworkTransport
-	done chan struct{}
+	done   chan struct{}
+	closed bool
 }
 
 // NewNodeTransport returns an initialized NodeTransport.
@@ -64,6 +65,11 @@ func NewNodeTransport(transport *raft.NetworkTransport) *NodeTransport {
 
 // Close closes the transport
 func (n *NodeTransport) Close() error {
+	if n.closed {
+		return nil
+	}
+	n.closed = true
+
 	close(n.done)
 	if n.NetworkTransport == nil {
 		return nil

store/transport_test.go

@@ -18,4 +18,7 @@ func Test_NewNodeTransport(t *testing.T) {
 	if err := nt.Close(); err != nil {
 		t.Fatalf("failed to close NodeTransport: %s", err.Error())
 	}
+	if err := nt.Close(); err != nil {
+		t.Fatalf("failed to double-close NodeTransport: %s", err.Error())
+	}
 }