/// <summary>
/// Attempts to commit changing the configuration if a consensus exists at this point.
/// Otherwise a join is performed.
/// If a consensus is lost before the desired configuration was reached, it is instantly applied.
///
/// </summary>
/// <param name="cfg"></param>
public void ChangeConfiguration(Configuration cfg)
{
DoSerialized(() =>
{
if (IsInConsensus)
{
cfgChange = new ConfigurationChange(cfg);
cfgChangeAt = DateTime.Now;
Schedule(cfgChange);
}
else
{
cfgChange = null;
Join(cfg);
}
});
}
internal void Join(Configuration cfg)
{
List <Connection> doDispose = new List <Connection>();
DoSerialized(() =>
{
if (cfgChange != null && cfgChange.NewCFG == cfg)
{
LogMinorEvent("Recognized requested cfg");
cfgChange = null;
}
if (cfg == config)
{
return;
}
LogEvent("Implementing consensus configuration " + cfg);
int at;
if (!cfg.ToIndex(MemberID, out at))
{
LogError("Local member ID " + MemberID + " is not part of new consensus configuration " + cfg + ". Closing down node");
OnOutOfConfig(cfg);
Dispose();
throw new ArgumentException("Local member ID " + MemberID + " is not part of new consensus configuration " + cfg);
}
MemberID = cfg.Members[at];
MyLinearIndex = at;
var newMembers = new Connection[cfg.Size];
if (remoteMembers != null)
{
foreach (var m in remoteMembers)
{
if (m == null)
{
continue;
}
int linear;
if (cfg.ToIndex(m.RemoteIdentifier, out linear) && m.IsActive == linear > MyLinearIndex && m.RemoteIdentifier == cfg.Members[linear])
{
if (at == linear)
{
throw new InvalidOperationException("Found self among remotes");
}
newMembers[linear] = m;
}
else
{
doDispose.Add(m);
}
}
}
config = cfg;
for (int i = MyLinearIndex + 1; i < cfg.Size; i++)
{
if (newMembers[i] == null)
{
newMembers[i] = new ActiveConnection(this, cfg.Members[i]);
}
}
remoteMembers = newMembers;
if (IsLeader)
{
if (!MemberID.CanBeLeader)
{
Yield();
}
}
else
{
var l = leader as Connection;
int linear;
if (l != null && (!cfg.ToIndex(l.RemoteIdentifier, out linear) || !cfg.Members[linear].CanBeLeader))
{
Yield();
}
}
});
foreach (var d in doDispose)
{
d.Dispose();
}
}
