From 059403e6731d18d687d2ac099f721a6ab1219b2f Mon Sep 17 00:00:00 2001
From: Matt Jaffee <jaffee@umbel.com>
Date: Mon, 17 Apr 2017 22:31:32 -0500
Subject: [PATCH] add stateHandler interface to gossip

now it doesn't need to directly reference pilosa.Server
---
 gossip.go | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/gossip.go b/gossip.go
index 1224cf69b..664b91aa7 100644
--- a/gossip.go
+++ b/gossip.go
@@ -13,6 +13,14 @@ import (
 	"github.com/pilosa/pilosa/internal"
 )
 
+// StateHandler specifies two methods which an object must implement to share
+// state in the cluster. These are used by the GossipNodeSet to implement the
+// LocalState and MergeRemoteState methods of memberlist.Delegate
+type StateHandler interface {
+	LocalState() (proto.Message, error)
+	HandleRemoteState(proto.Message) error
+}
+
 // GossipNodeSet represents a gossip implementation of NodeSet using memberlist
 // GossipNodeSet also represents a gossip implementation of pilosa.Broadcaster
 // GossipNodeSet also represents an implementation of memberlist.Delegate
@@ -22,9 +30,8 @@ type GossipNodeSet struct {
 
 	broadcasts *memberlist.TransmitLimitedQueue
 
-	server *Server
-
-	config *GossipConfig
+	stateHandler StateHandler
+	config       *GossipConfig
 
 	// The writer for any logging.
 	LogOutput io.Writer
@@ -81,7 +88,7 @@ type GossipConfig struct {
 }
 
 // NewGossipNodeSet returns a new instance of GossipNodeSet.
-func NewGossipNodeSet(name string, gossipHost string, gossipPort int, gossipSeed string, s *Server) *GossipNodeSet {
+func NewGossipNodeSet(name string, gossipHost string, gossipPort int, gossipSeed string, sh StateHandler) *GossipNodeSet {
 	g := &GossipNodeSet{
 		LogOutput: os.Stderr,
 	}
@@ -98,7 +105,7 @@ func NewGossipNodeSet(name string, gossipHost string, gossipPort int, gossipSeed
 	g.config.memberlistConfig.AdvertisePort = gossipPort
 	g.config.memberlistConfig.Delegate = g
 
-	g.server = s
+	g.stateHandler = sh
 
 	return g
 }
@@ -110,7 +117,7 @@ func (g *GossipNodeSet) SendSync(pb proto.Message) error {
 		return err
 	}
 
-	mlist := g.server.Cluster.NodeSet.(*GossipNodeSet).memberlist
+	mlist := g.memberlist
 
 	// Direct sends the message directly to every node.
 	// An error from any node raises an error on the entire operation.
@@ -175,7 +182,7 @@ func (g *GossipNodeSet) GetBroadcasts(overhead, limit int) [][]byte {
 }
 
 func (g *GossipNodeSet) LocalState(join bool) []byte {
-	pb, err := g.server.LocalState()
+	pb, err := g.stateHandler.LocalState()
 	if err != nil {
 		g.logger().Printf("error getting local state, err=%s", err)
 		return []byte{}
@@ -197,7 +204,7 @@ func (g *GossipNodeSet) MergeRemoteState(buf []byte, join bool) {
 		g.logger().Printf("error unmarshalling nodestate data, err=%s", err)
 		return
 	}
-	err := g.server.HandleRemoteState(&pb)
+	err := g.stateHandler.HandleRemoteState(&pb)
 	if err != nil {
 		g.logger().Printf("merge state error: %s", err)
 	}