From 1ec537450e4f4d48ad12a32d8e136a74fadebd2a Mon Sep 17 00:00:00 2001
From: Sean Chittenden <sean@chittenden.org>
Date: Thu, 2 Jun 2016 00:12:30 -0700
Subject: [PATCH] Rename rpcproxy.UpdateFromNodeUpdateResponse to
 RefreshServerLists

While breaking the API within this PR, break out the individual
arguments to RefreshServerLists.  The servers parameter is reusing
`structs.NodeServerInfo` for the time being, but this can be revisited
if the needs of the strucutre diverge in the future.
---
 client/client.go            |  2 +-
 client/rpcproxy/rpcproxy.go | 32 +++++++++++++++++---------------
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/client/client.go b/client/client.go
index a85dad3ee..3ac5bce95 100644
--- a/client/client.go
+++ b/client/client.go
@@ -915,7 +915,7 @@ func (c *Client) updateNodeStatus() error {
 	c.lastHeartbeat = time.Now()
 	c.heartbeatTTL = resp.HeartbeatTTL
 
-	if err := c.rpcProxy.UpdateFromNodeUpdateResponse(&resp); err != nil {
+	if err := c.rpcProxy.RefreshServerLists(resp.Servers, resp.NumNodes, resp.LeaderRPCAddr); err != nil {
 		return err
 	}
 	c.consulPullHeartbeatDeadline = time.Now().Add(2 * resp.HeartbeatTTL)
diff --git a/client/rpcproxy/rpcproxy.go b/client/rpcproxy/rpcproxy.go
index 18ee9053d..899f0434b 100644
--- a/client/rpcproxy/rpcproxy.go
+++ b/client/rpcproxy/rpcproxy.go
@@ -631,14 +631,16 @@ func (p *RpcProxy) Run() {
 	}
 }
 
-// UpdateFromNodeUpdateResponse handles heartbeat responses from Nomad
-// Servers.  Heartbeats contain a list of Nomad Servers that the client
-// should talk with for RPC requests.  UpdateFromNodeUpdateResponse does not
-// rebalance its serverList, that is handled elsewhere.  New servers learned
-// via the heartbeat are appended to the RpcProxy's serverList.  Removed
-// servers are removed immediately.  Servers speaking a newer RPC version are
-// filtered from the serverList.
-func (p *RpcProxy) UpdateFromNodeUpdateResponse(resp *structs.NodeUpdateResponse) error {
+// RefreshServerLists is called when the Client receives an update from a
+// Nomad Server.  The response from Nomad Client Heartbeats contain a list of
+// Nomad Servers that the Nomad Client should use for RPC requests.
+// RefreshServerLists does not rebalance its serverLists (that is handled
+// elsewhere via a periodic timer).  New Nomad Servers learned via the
+// heartbeat are appended to the RpcProxy's activated serverList.  Servers
+// that are no longer present in the Heartbeat are removed immediately from
+// all server lists.  Nomad Servers speaking a newer major or minor API
+// version are filtered from the serverList.
+func (p *RpcProxy) RefreshServerLists(servers []*structs.NodeServerInfo, numNodes int32, leaderRpcAddr string) error {
 	// Merge all servers found in the response.  Servers in the response
 	// with newer API versions are filtered from the list.  If the list
 	// is missing an address found in the RpcProxy's server list, remove
@@ -655,12 +657,12 @@ func (p *RpcProxy) UpdateFromNodeUpdateResponse(resp *structs.NodeUpdateResponse
 
 	// Clear the backup server list when a heartbeat contains at least
 	// one server.
-	if len(resp.Servers) > 0 && len(p.backupServers.L) > 0 {
-		p.backupServers.L = make([]*ServerEndpoint, 0, len(resp.Servers))
+	if len(servers) > 0 && len(p.backupServers.L) > 0 {
+		p.backupServers.L = make([]*ServerEndpoint, 0, len(servers))
 	}
 
 	// 1) Create a map to reconcile the difference between
-	// p.primaryServers and resp.Servers.
+	// p.primaryServers and servers.
 	type targetServer struct {
 		server *ServerEndpoint
 
@@ -669,7 +671,7 @@ func (p *RpcProxy) UpdateFromNodeUpdateResponse(resp *structs.NodeUpdateResponse
 		//   'n' == new
 		state byte
 	}
-	mergedPrimaryMap := make(map[EndpointKey]*targetServer, len(p.primaryServers.L)+len(resp.Servers))
+	mergedPrimaryMap := make(map[EndpointKey]*targetServer, len(p.primaryServers.L)+len(servers))
 	numOldServers := 0
 	for _, s := range p.primaryServers.L {
 		mergedPrimaryMap[*s.Key()] = &targetServer{server: s, state: 'o'}
@@ -677,7 +679,7 @@ func (p *RpcProxy) UpdateFromNodeUpdateResponse(resp *structs.NodeUpdateResponse
 	}
 	numBothServers := 0
 	var newServers bool
-	for _, s := range resp.Servers {
+	for _, s := range servers {
 		// Filter out servers using a newer API version.  Prevent
 		// spamming the logs every heartbeat.
 		//
@@ -758,8 +760,8 @@ func (p *RpcProxy) UpdateFromNodeUpdateResponse(resp *structs.NodeUpdateResponse
 		}
 	}
 
-	p.numNodes = int(resp.NumNodes)
-	p.leaderAddr = resp.LeaderRPCAddr
+	p.numNodes = int(numNodes)
+	p.leaderAddr = leaderRpcAddr
 	p.saveServerList(newServerCfg)
 
 	return nil