/* This function aborts a non blocking replication attempt if there is one
* in progress, by canceling the non-blocking connect attempt or
* the initial bulk transfer.
*
* If there was a replication handshake in progress 1 is returned and
* the replication state (server.repl_state) set to REDIS_REPL_CONNECT.
*
* Otherwise zero is returned and no operation is perforemd at all. */
int cancelReplicationHandshake(void) {
if (server.repl_state == REDIS_REPL_TRANSFER) {
replicationAbortSyncTransfer();
} else if (server.repl_state == REDIS_REPL_CONNECTING ||
server.repl_state == REDIS_REPL_RECEIVE_PONG)
{
undoConnectWithMaster();
} else {
return 0;
}
return 1;
}
void slaveofCommand(redisClient *c) {
if (!strcasecmp(c->argv[1]->ptr,"no") &&
!strcasecmp(c->argv[2]->ptr,"one")) {
if (server.masterhost) {
sdsfree(server.masterhost);
server.masterhost = NULL;
if (server.master) freeClient(server.master);
if (server.repl_state == REDIS_REPL_TRANSFER)
replicationAbortSyncTransfer();
else if (server.repl_state == REDIS_REPL_CONNECTING ||
server.repl_state == REDIS_REPL_RECEIVE_PONG)
undoConnectWithMaster();
server.repl_state = REDIS_REPL_NONE;
redisLog(REDIS_NOTICE,"MASTER MODE enabled (user request)");
}
} else {
long port;
if ((getLongFromObjectOrReply(c, c->argv[2], &port, NULL) != REDIS_OK))
return;
/* Check if we are already attached to the specified slave */
if (server.masterhost && !strcasecmp(server.masterhost,c->argv[1]->ptr)
&& server.masterport == port) {
redisLog(REDIS_NOTICE,"SLAVE OF would result into synchronization with the master we are already connected with. No operation performed.");
addReplySds(c,sdsnew("+OK Already connected to specified master\r\n"));
return;
}
/* There was no previous master or the user specified a different one,
* we can continue. */
sdsfree(server.masterhost);
server.masterhost = sdsdup(c->argv[1]->ptr);
server.masterport = port;
if (server.master) freeClient(server.master);
disconnectSlaves(); /* Force our slaves to resync with us as well. */
if (server.repl_state == REDIS_REPL_TRANSFER)
replicationAbortSyncTransfer();
server.repl_state = REDIS_REPL_CONNECT;
redisLog(REDIS_NOTICE,"SLAVE OF %s:%d enabled (user request)",
server.masterhost, server.masterport);
}
addReply(c,shared.ok);
}
void replicationCron(void) {
/* Non blocking connection timeout? */
if (server.masterhost &&
(server.repl_state == REDIS_REPL_CONNECTING ||
server.repl_state == REDIS_REPL_RECEIVE_PONG) &&
(time(NULL)-server.repl_transfer_lastio) > server.repl_timeout)
{
redisLog(REDIS_WARNING,"Timeout connecting to the MASTER...");
undoConnectWithMaster();
}
/* Bulk transfer I/O timeout? */
if (server.masterhost && server.repl_state == REDIS_REPL_TRANSFER &&
(time(NULL)-server.repl_transfer_lastio) > server.repl_timeout)
{
redisLog(REDIS_WARNING,"Timeout receiving bulk data from MASTER... If the problem persists try to set the 'repl-timeout' parameter in redis.conf to a larger value.");
replicationAbortSyncTransfer();
}
/* Timed out master when we are an already connected slave? */
if (server.masterhost && server.repl_state == REDIS_REPL_CONNECTED &&
(time(NULL)-server.master->lastinteraction) > server.repl_timeout)
{
redisLog(REDIS_WARNING,"MASTER time out: no data nor PING received...");
freeClient(server.master);
}
/* Check if we should connect to a MASTER */
if (server.repl_state == REDIS_REPL_CONNECT) {
redisLog(REDIS_NOTICE,"Connecting to MASTER...");
if (connectWithMaster() == REDIS_OK) {
redisLog(REDIS_NOTICE,"MASTER <-> SLAVE sync started");
}
}
/* If we have attached slaves, PING them from time to time.
* So slaves can implement an explicit timeout to masters, and will
* be able to detect a link disconnection even if the TCP connection
* will not actually go down. */
if (!(server.cronloops % (server.repl_ping_slave_period * REDIS_HZ))) {
listIter li;
listNode *ln;
listRewind(server.slaves,&li);
while((ln = listNext(&li))) {
redisClient *slave = ln->value;
/* Don't ping slaves that are in the middle of a bulk transfer
* with the master for first synchronization. */
if (slave->replstate == REDIS_REPL_SEND_BULK) continue;
if (slave->replstate == REDIS_REPL_ONLINE) {
/* If the slave is online send a normal ping */
addReplySds(slave,sdsnew("*1\r\n$4\r\nPING\r\n"));
} else {
/* Otherwise we are in the pre-synchronization stage.
* Just a newline will do the work of refreshing the
* connection last interaction time, and at the same time
* we'll be sure that being a single char there are no
* short-write problems. */
if (write(slave->fd, "\n", 1) == -1) {
/* Don't worry, it's just a ping. */
}
}
}
}
}