// getUpdatesFromPeer receives node data from the peer
// for which the peer has more latest information available
func (g *GossiperImpl) getUpdatesFromPeer(conn types.MessageChannel) error {
var newPeerData types.StoreDiff
err := conn.RcvData(&newPeerData)
if err != nil {
log.Error("Error fetching the latest peer data", err)
return err
}
g.Update(newPeerData)
return nil
}
func (g *GossiperImpl) handleGossip(peerId string, conn types.MessageChannel) {
log.Debug(g.id, " Servicing gossip request")
var peerMetaInfo types.StoreMetaInfo
err := error(nil)
g.updateSelfTs()
// Get the info about the node data that the sender has
err = conn.RcvData(&peerMetaInfo)
log.Debug(g.id, " Got meta data: \n", peerMetaInfo)
if err != nil {
return
}
// 2. Compare with current data that this node has and get
// the names of the nodes for which this node has stale info
// as compared to the sender
diffNew, selfNew := g.Diff(peerMetaInfo)
log.Debug(g.id, " The diff is: diffNew: \n", diffNew, " \nselfNew:\n", selfNew)
// Send this list to the peer, and get the latest data
// for them
err = conn.SendData(diffNew)
if err != nil {
log.Error("Error sending list of nodes to fetch: ", err)
return
}
// get the data for nodes sent above from the peer
err = g.getUpdatesFromPeer(conn)
if err != nil {
log.Error("Failed to get data for nodes from the peer: ", err)
return
}
// Since you know which data is stale on the sender side,
// send him the data for the updated nodes
err = g.sendUpdatesToPeer(&selfNew, conn)
if err != nil {
return
}
log.Debug(g.id, " Finished Servicing gossip request")
g.history.AddLatest(NewGossipSessionInfo(peerId, types.GD_PEER_TO_ME))
g.updateGossipTs()
}
// sendUpdatesToPeer sends the information about the given
// nodes to the peer
func (g *GossiperImpl) sendUpdatesToPeer(diff *types.StoreNodes,
conn types.MessageChannel) error {
dataToSend := g.Subset(*diff)
return conn.SendData(&dataToSend)
}
// sendNodeMetaInfo sends a list of meta info for all
// the nodes in the nodes's store to the peer
func (g *GossiperImpl) sendNodeMetaInfo(conn types.MessageChannel) error {
msg := g.MetaInfo()
err := conn.SendData(&msg)
return err
}