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Mutate copies of serverCfg.servers, not original 

Removing any ambiguity re: ownership of the mutated server lists is a win for maintenance and debugging.
This commit is contained in:
Sean Chittenden 2016-02-19 19:01:46 -08:00
parent 753766cc5d
commit c1c17f158b
1 changed files with 22 additions and 9 deletions
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31
consul/server_manager/server_manager.go
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@ -105,9 +105,14 @@ func (sm *ServerManager) AddServer(server *server_details.ServerDetails) {
found := false found := false
for idx, existing := range serverCfg.servers { for idx, existing := range serverCfg.servers {
if existing.Name == server.Name { if existing.Name == server.Name {
// Overwrite the existing server parts in order to newServers := make([]*server_details.ServerDetails, len(serverCfg.servers))
// possibly update metadata (i.e. server version) copy(newServers, serverCfg.servers)
serverCfg.servers[idx] = server
// Overwrite the existing server details in order to
// possibly update metadata (e.g. server version)
newServers[idx] = server
serverCfg.servers = newServers
found = true found = true
break break
} }
@ -240,13 +245,17 @@ func (sm *ServerManager) RebalanceServers() {
defer sm.serverConfigLock.Unlock() defer sm.serverConfigLock.Unlock()
serverCfg := sm.getServerConfig() serverCfg := sm.getServerConfig()
newServers := make([]*server_details.ServerDetails, len(serverCfg.servers)+1)
copy(newServers, serverCfg.servers)
// Shuffle the server list on server join. Servers are selected from // Shuffle the server list on server join. Servers are selected from
// the head of the list and are moved to the end of the list on // the head of the list and are moved to the end of the list on
// failure. // failure.
for i := len(serverCfg.servers) - 1; i > 0; i-- { for i := len(serverCfg.servers) - 1; i > 0; i-- {
j := rand.Int31n(int32(i + 1)) j := rand.Int31n(int32(i + 1))
serverCfg.servers[i], serverCfg.servers[j] = serverCfg.servers[j], serverCfg.servers[i] newServers[i], newServers[j] = newServers[j], newServers[i]
} }
serverCfg.servers = newServers
serverCfg.resetRebalanceTimer(sm) serverCfg.resetRebalanceTimer(sm)
sm.serverConfigValue.Store(serverCfg) sm.serverConfigValue.Store(serverCfg)
@ -267,13 +276,17 @@ func (sm *ServerManager) RemoveServer(server *server_details.ServerDetails) {
n := len(serverCfg.servers) n := len(serverCfg.servers)
for i := 0; i < n; i++ { for i := 0; i < n; i++ {
if serverCfg.servers[i].Name == server.Name { if serverCfg.servers[i].Name == server.Name {
serverCfg.servers[i], serverCfg.servers[n-1] = serverCfg.servers[n-1], nil newServers := make([]*server_details.ServerDetails, len(serverCfg.servers)-1)
serverCfg.servers = serverCfg.servers[:n-1] copy(newServers, serverCfg.servers)
break
} newServers[i], newServers[n-1] = newServers[n-1], nil
} newServers = newServers[:n-1]
serverCfg.servers = newServers
sm.serverConfigValue.Store(serverCfg) sm.serverConfigValue.Store(serverCfg)
return
}
}
} }
// resetRebalanceTimer assumes: // resetRebalanceTimer assumes: