int TDB_replica_leader(TDB_replica_t* replica)
{
UT_array* replica_hooks;
UT_array* log;
TDB_addr_t* vote;
uint64_t term;
uint32_t heartbeat_result = 0;
int default_leader_heartbeat = 5000;
static Alt alts[TDB_REPLICA_LEADER_ALT_NK + 1];
TDB_attach_msg_t data_attach_msg;
data_attach_msg.msg = NULL;
TDB_msg_data_t* data_msg;
TDB_msg_data_resp_t* data_msg_resp = (TDB_msg_data_resp_t*) malloc(sizeof(TDB_msg_data_resp_t));
//LOG(TDB_LOG_INFO, "Replica has entered leader state.");
// TODO: Initialize nextIndex for each follower to the local last log index + 1.
if(TDB_timer_init(&(replica->election_timer)) != TDB_SUCCESS) {
LOG(TDB_LOG_ERR, "Could not allocate a heartbeat timer for this leader replica.");
return TDB_ERROR;
}
alts[TDB_REPLICA_LEADER_ALT_DATA_KEY].c = replica->data_chan;
alts[TDB_REPLICA_LEADER_ALT_DATA_KEY].v = &data_attach_msg;
alts[TDB_REPLICA_LEADER_ALT_DATA_KEY].op = CHANRCV;
alts[TDB_REPLICA_LEADER_ALT_TIMER_KEY].c = replica->election_timer->alarm_chan;
alts[TDB_REPLICA_LEADER_ALT_TIMER_KEY].v = &heartbeat_result;
alts[TDB_REPLICA_LEADER_ALT_TIMER_KEY].op = CHANRCV;
// TODO: Send initial empty AppendEntries RPCs (heartbeat) to each follower.
TDB_timer_start(replica->election_timer, default_leader_heartbeat);
switch(chanalt(alts)) {
case TDB_REPLICA_LEADER_ALT_DATA_KEY:
LOG(TDB_LOG_DBG, "This leader received a data message.");
if(data_attach_msg.msg == NULL) {
LOG(TDB_LOG_DBG, "Received an attach wrapper without a valid message.");
break;
}
data_msg = data_attach_msg.msg;
TDB_proto_print_data_msg(data_msg);
data_msg_resp->success = TDB_PROTO_DATA_R_OK;
data_msg_resp->err_code = 0;
chansendp(data_attach_msg.data_reply_chan, data_msg_resp);
// TODO: Append data messages to local log.
// Pack and append to local log.
//TDB_clnt_proto_pack_data_msgpack(client_data_msg, &op_packed_len, &op_packed);
//TDB_replica_append_to_log(replica, op_packed, op_packed_len);
// TODO: Whenever last log index is greater or equal to nextIndex for a follower:
// 1. Send AppendEntries RPC with log entries starting at nextIndex.
// a. Update nextIndex if successful.
// b. If AppendEntries fails because of log inconsistency, decrement
// nextIndex and retry.
// TODO: Mark entries commited if stored on a majority of servers and some entry
// from current term is stored on a majority of servers. Apply newly committed
// entries to state machine.
// TODO: Step down if currentTerm changes.
break;
case TDB_REPLICA_LEADER_ALT_TIMER_KEY:
LOG(TDB_LOG_DBG, "This leader received a heartbeat alarm.");
// TODO: Send empty append messages (heartbeat) to each follower.
break;
default:
LOG(TDB_LOG_ERR, "Unknown index received for leader alt array.");
break;
}
return TDB_SUCCESS;
}
int
chansendp(Channel *c, void *v)
{
return chansendp(c, &v);
}
