// Replica metadata server append to log
public override void AppendToLog(MetadataServer md, string command)
{
string[] args = command.Split(' ');
string code = args[0];
switch (code)
{
case "CREATE":
{
string clientName = args[1];
string filename = args[2];
int serversNumber = int.Parse(args[3]);
int readQuorum = int.Parse(args[4]);
int writeQuorum = int.Parse(args[5]);
if (!md.Files.ContainsKey(filename))
{
if (md.LiveDataServers.Count < serversNumber)
{
if (!md.PendingFiles.ContainsKey(filename))
{
md.PendingFiles.Add(filename, serversNumber - md.LiveDataServers.Count);
}
}
List<string> servers = new List<string>();
string[] chosen = Util.SliceArray(args, 6, args.Length);
// Before sending the requests, a time stamp is added to the filename
foreach (string v in chosen)
{
servers.Add(md.LiveDataServers[v]);
md.ServersLoad[v]++;
}
md.ServersLoad = Util.SortServerLoad(md.ServersLoad);
Metadata meta = new Metadata(filename, serversNumber, readQuorum, writeQuorum, servers);
List<string> clientsList = new List<string>();
clientsList.Add(clientName);
md.Files.Add(filename, meta);
md.OpenFiles.Add(filename, clientsList);
}
}
break;
case "OPEN":
{
string clientName = args[1];
string filename = args[2];
if (md.OpenFiles.ContainsKey(filename))
{
List<string> clientsList = md.OpenFiles[filename];
if (!clientsList.Contains(clientName))
{
md.OpenFiles[filename].Add(clientName);
}
}
else
{
if (md.Files.ContainsKey(filename))
{
List<string> clientsList = new List<string>();
clientsList.Add(clientName);
md.OpenFiles.Add(filename, clientsList);
}
}
}
break;
case "CLOSE":
{
string clientName = args[1];
string filename = args[2];
if (md.Files.ContainsKey(filename))
{
if (md.OpenFiles.ContainsKey(filename))
{
List<string> clientsList = md.OpenFiles[filename];
if (clientsList.Contains(clientName))
{
clientsList.Remove(clientName);
if (clientsList.Count == 0)
{
md.OpenFiles.Remove(filename);
}
}
}
}
}
break;
case "DELETE":
{
string clientName = args[1];
string filename = args[2];
string[] servers = Util.SliceArray(args, 3, args.Length);
if (md.Files.ContainsKey(filename))
{
md.Files.Remove(filename);
md.OpenFiles.Remove(filename);
foreach (string server in servers)
{
md.ServersLoad[server]--;
}
md.ServersLoad = Util.SortServerLoad(md.ServersLoad);
}
}
break;
case "REGISTER":
{
string server = args[1];
string name = args[2];
string address = args[3];
switch (server)
{
case "data":
if (!md.DataServersInfo.ContainsKey(name))
{
md.LiveDataServers.Add(name, address);
md.DataServersInfo.Add(name, null);
md.ServersLoad.Add(name, 0);
}
break;
case "metadata":
if (!md.Replicas.ContainsKey(name) && name != md.Name)
{
md.Replicas.Add(name, address);
}
break;
case "client":
if (!md.Clients.ContainsKey(name))
{
md.Clients.Add(name, address);
}
break;
}
}
break;
case "UPDATE":
{
string name = args[1];
string address = args[2];
string[] files = Util.SliceArray(args, 3, args.Length);
SerializableDictionary<string, int> updated = new SerializableDictionary<string, int>();
bool contains = false;
foreach (string f in files)
{
Metadata meta = md.Files[f];
meta.AddDataServers(address);
md.ServersLoad[name]++;
md.ServersLoad = Util.SortServerLoad(md.ServersLoad);
if (md.PendingFiles.ContainsKey(f))
{
int n = md.PendingFiles[f] - 1;
if (n > 0)
{
updated.Add(f, n);
}
contains = true;
}
}
if (contains)
{
md.PendingFiles = new SerializableDictionary<string, int>(updated);
}
}
break;
case "SET-PRIMARY":
{
string primary = args[1];
md.Primary = primary;
if (md.Primary == md.Name)
{
md.EnablePrimaryTimers();
}
else
{
md.EnableReplicaTimers();
}
}
break;
case "TOKEN":
{
long s = long.Parse(args[1]);
md.Sequencer = s;
}
break;
}
md.Log.Append(command);
}
// Method used to add a new/open file to a free file register
// Limit - 10
private void AddToFileRegister(Metadata meta)
{
fileRegister[nextRegister] = meta;
nextRegister = (nextRegister + 1) % registersLimit;
}
public override Metadata Create(MetadataServer md, string clientName, string filename, int serversNumber, int readQuorum, int writeQuorum)
{
if (md.Files.ContainsKey(filename))
{
throw new FileAlreadyExists("File already exists.");
}
if (md.LiveDataServers.Count < serversNumber)
{
if (!md.PendingFiles.ContainsKey(filename))
{
md.PendingFiles.Add(filename, serversNumber - md.LiveDataServers.Count);
}
}
List<string> servers = new List<string>();
List<string> chosen = ChooseBestServers(serversNumber, md);
// Before sending the requests, a time stamp is added to the filename
string f = md.GetToken().ToString() + (char)0x7f + filename;
foreach (string v in chosen)
{
List<string> arguments = new List<string>();
arguments.Add(md.LiveDataServers[v]);
arguments.Add(f);
servers.Add(md.LiveDataServers[v]);
ThreadPool.QueueUserWorkItem(CreateCallback, arguments);
md.ServersLoad[v]++;
}
LoadBalanceServers(md);
Metadata meta = new Metadata(filename, serversNumber, readQuorum, writeQuorum, servers);
List<string> clientsList = new List<string>();
clientsList.Add(clientName);
md.Files.Add(filename, meta);
md.OpenFiles.Add(filename, clientsList);
List<object> context = new List<object>();
context.Add(md);
string command = string.Format("CREATE {0} {1} {2} {3} {4}", clientName, filename, serversNumber, readQuorum, writeQuorum);
foreach (string c in chosen)
{
command += string.Format(" {0}", c);
}
context.Add(command);
ThreadPool.QueueUserWorkItem(AppendToLog, context);
md.Log.Append(command);
return meta;
}
public void UpdateFileMetadata(string filename, Metadata metadata)
{
if (openFiles.ContainsKey(filename))
{
openFiles[filename] = metadata;
for (int i = 0; i < registersLimit; i++)
{
if (fileRegister[i] != null && fileRegister[i].Filename == filename)
{
fileRegister[i] = metadata;
break;
}
}
}
}