public ReplHandler getReplicatedDatabase_Fresh(string server_guid)
{
ServerContext ctx = new ServerContext();
ctx.server_guid = server_guid;
ctx.connector = connector;
return ReplHandler.InitFresh(new StepsStageSnapshot(new StepsStageSubset(new RecordKeyType_String(ctx.server_guid), this.db)), ctx);
}
public ReplHandler getReplicatedDatabase_Join(string new_server_guid, string join_server_guid)
{
ServerContext ctx = new ServerContext();
ctx.server_guid = new_server_guid;
ctx.connector = connector;
return ReplHandler.InitJoin(
new StepsStageSnapshot(new StepsStageSubset(new RecordKeyType_String(ctx.server_guid), this.db)),
ctx,
join_server_guid);
}
public static ReplHandler InitResume(IStepsSnapshotKVDB db, ServerContext ctx)
{
ReplHandler repl = new ReplHandler(db, ctx);
return repl;
}
public static ReplHandler InitJoin(IStepsSnapshotKVDB db, ServerContext ctx, string seed_name)
{
// connect to the other server, get his instance id, exchange seeds
IReplConnection seed = ctx.connector.getServerHandle(seed_name);
JoinInfo join_info = seed.requestToJoin(ctx.server_guid);
// record the join result
db.setValue(new RecordKey()
.appendKeyPart("_config")
.appendKeyPart("DATA-INSTANCE-ID"),
RecordUpdate.WithPayload(join_info.data_instance_id));
// init a clean log
db.setValue(new RecordKey()
.appendKeyPart("_logs")
.appendKeyPart(ctx.server_guid)
.appendKeyPart(new RecordKeyType_Long(0)),
RecordUpdate.WithPayload(new byte[0]));
foreach (var seed_server in join_info.seed_servers) {
db.setValue(new RecordKey()
.appendKeyPart("_config")
.appendKeyPart("seeds")
.appendKeyPart(seed_server),
RecordUpdate.WithPayload(""));
}
Console.WriteLine("InitJoin: server ({0}) joining seeds ({1})",
ctx.server_guid, String.Join(",", join_info.seed_servers));
ReplHandler repl = new ReplHandler(db, ctx);
return repl;
}
public static ReplHandler InitFresh(IStepsSnapshotKVDB db, ServerContext ctx)
{
// init fresh
// record our instance ID
db.setValue(new RecordKey()
.appendKeyPart("_config")
.appendKeyPart("MY-SERVER-ID"),
RecordUpdate.WithPayload(ctx.server_guid));
// create and record a new instance ID
db.setValue(new RecordKey()
.appendKeyPart("_config")
.appendKeyPart("DATA-INSTANCE-ID"),
RecordUpdate.WithPayload(Lsd.numberToLsd(ReplHandler.myrnd.Next(), 15)));
// record the "start of fresh log" record
db.setValue(new RecordKey()
.appendKeyPart("_logs")
.appendKeyPart(ctx.server_guid)
.appendKeyPart(new RecordKeyType_Long(0)),
RecordUpdate.WithPayload(new byte[0]));
// record ourself as a seed/log
db.setValue(new RecordKey()
.appendKeyPart("_config").appendKeyPart("seeds").appendKeyPart(ctx.server_guid),
RecordUpdate.WithPayload(""));
ReplHandler repl = new ReplHandler(db, ctx);
repl.state = ReplState.active; // TODO: is this the right way to become active?
return repl;
}
public ReplHandler(IStepsSnapshotKVDB db, ServerContext ctx)
{
this.next_stage = db;
this.my_repl_interface = new MyReplConnection(this);
this.rnd = new Random();
this.pusher = new ReplPusher(this);
this.ctx = ctx;
try {
var di_rk = new RecordKey()
.appendKeyPart("_config")
.appendKeyPart("DATA-INSTANCE-ID");
var rec = db.FindNext(di_rk, true);
if (di_rk.CompareTo(rec.Key) != 0) {
throw new Exception(
String.Format("ReplHandler {0} , not able to fetch DATA-INSTANCE-ID", ctx.server_guid));
}
this.data_instance_id = rec.Value.ToString();
Console.WriteLine("ReplHandler - {0}: data_instance_id {1}",
ctx.server_guid, data_instance_id);
} catch (KeyNotFoundException) {
throw new Exception("no data instance ID, try InitResume or InitJoin");
}
// check server_guid matches?
// register ourself
ctx.connector.registerServer(ctx.server_guid, this.my_repl_interface);
// startup our background task
worker = new Thread(delegate() {
this.workerThread();
});
worker.Start();
}