public GrantPermissionReply GrantPermissionToBecomeLeaderHandler(GrantPermissionRequest request)
{
server.becomeLeader(request.PartitionId);
return(new GrantPermissionReply {
Status = "OK"
});
}
public string ElectPartitionMaster(string partitionId, string crashedMasterServerId)
{
Dictionary <string, int> partition_clocks = new Dictionary <string, int>();
string new_leader_id = "";
Partition partition = server.getPartition(partitionId);
Dictionary <string, ServerCommunicationService.ServerCommunicationServiceClient> partitionReplicas = partition.getReplicas();
foreach (string replica_id in partitionReplicas.Keys)
{
try
{
ClockReply reply = partitionReplicas[replica_id].GetPartitionClock(new ClockRequest
{
PartitionId = partitionId,
});
partition_clocks[replica_id] = reply.Clock;
}
catch (Exception)
{
Console.WriteLine("Replica cannot be reached: " + replica_id);
}
}
if (partition_clocks.Count == 0)
{
new_leader_id = this.server.getID();
server.becomeLeader(partitionId);
}
else
{
// find highest clock
int largest_clock = partition_clocks.Values.Max();
// filter servers by their clock
Dictionary <string, int> valid_leaders_list = partition_clocks.Where(x => x.Value == largest_clock).ToDictionary(i => i.Key, i => i.Value);
// now to find the valid leader with highest ID
string[] replicas_ordered_by_id = Shared.Util.PartitionMapping.GetPartitionReplicas(partitionId);
for (int i = 0; i < replicas_ordered_by_id.Length; i++)
{
string server = replicas_ordered_by_id[i];
if (valid_leaders_list.Keys.Contains(server))
{
new_leader_id = server;
// send message granting permission to be a leader
partitionReplicas[new_leader_id].GrantPermissionToBecomeLeader(new GrantPermissionRequest
{
PartitionId = partitionId,
});
break;
}
}
}
return(new_leader_id);
}