/**
* Get a Redis object with a connection suitable for fetching the specified key
* @return Array (server, RedisConnRef) or (false, false)
*/
protected function getConnection( $key ) {
if ( count( $this->servers ) === 1 ) {
$candidates = $this->servers;
} else {
$candidates = $this->servers;
ArrayUtils::consistentHashSort( $candidates, $key, '/' );
if ( !$this->automaticFailover ) {
$candidates = array_slice( $candidates, 0, 1 );
}
}
foreach ( $candidates as $server ) {
$conn = $this->redisPool->getConnection( $server );
if ( $conn ) {
return array( $server, $conn );
}
}
return array( false, false );
}
/**
* Get a Redis object with a connection suitable for fetching the specified key
* @param string $key
* @return array (server, RedisConnRef) or (false, false)
*/
protected function getConnection($key)
{
$candidates = array_keys($this->serverTagMap);
if (count($this->servers) > 1) {
ArrayUtils::consistentHashSort($candidates, $key, '/');
if (!$this->automaticFailover) {
$candidates = array_slice($candidates, 0, 1);
}
}
while (($tag = array_shift($candidates)) !== null) {
$server = $this->serverTagMap[$tag];
$conn = $this->redisPool->getConnection($server);
if (!$conn) {
continue;
}
// If automatic failover is enabled, check that the server's link
// to its master (if any) is up -- but only if there are other
// viable candidates left to consider. Also, getMasterLinkStatus()
// does not work with twemproxy, though $candidates will be empty
// by now in such cases.
if ($this->automaticFailover && $candidates) {
try {
if ($this->getMasterLinkStatus($conn) === 'down') {
// If the master cannot be reached, fail-over to the next server.
// If masters are in data-center A, and slaves in data-center B,
// this helps avoid the case were fail-over happens in A but not
// to the corresponding server in B (e.g. read/write mismatch).
continue;
}
} catch (RedisException $e) {
// Server is not accepting commands
$this->handleException($conn, $e);
continue;
}
}
return array($server, $conn);
}
$this->setLastError(BagOStuff::ERR_UNREACHABLE);
return array(false, false);
}
/**
* @return Status Uses RediConnRef as value on success
*/
protected function getConnection()
{
if (!isset($this->conn)) {
$conn = false;
$servers = $this->ring->getLocations($this->key, 3);
ArrayUtils::consistentHashSort($servers, $this->key);
foreach ($servers as $server) {
$conn = $this->pool->getConnection($this->serversByLabel[$server], $this->logger);
if ($conn) {
break;
}
}
if (!$conn) {
return Status::newFatal('pool-servererror', implode(', ', $servers));
}
$this->conn = $conn;
}
return Status::newGood($this->conn);
}
/**
* Get the server index and table name for a given key
* @param string $key
* @return array Server index and table name
*/
protected function getTableByKey($key)
{
if ($this->shards > 1) {
$hash = hexdec(substr(md5($key), 0, 8)) & 0x7fffffff;
$tableIndex = $hash % $this->shards;
} else {
$tableIndex = 0;
}
if ($this->numServers > 1) {
$sortedServers = $this->serverNames;
ArrayUtils::consistentHashSort($sortedServers, $key);
reset($sortedServers);
$serverIndex = key($sortedServers);
} else {
$serverIndex = 0;
}
return array($serverIndex, $this->getTableNameByShard($tableIndex));
}
/**
* Get a Redis object with a connection suitable for fetching the specified key
* @param string $key
* @return array (server, RedisConnRef) or (false, false)
*/
protected function getConnection($key)
{
$candidates = array_keys($this->serverTagMap);
if (count($this->servers) > 1) {
ArrayUtils::consistentHashSort($candidates, $key, '/');
if (!$this->automaticFailover) {
$candidates = array_slice($candidates, 0, 1);
}
}
foreach ($candidates as $tag) {
$server = $this->serverTagMap[$tag];
$conn = $this->redisPool->getConnection($server);
if ($conn) {
return array($server, $conn);
}
}
$this->setLastError(BagOStuff::ERR_UNREACHABLE);
return array(false, false);
}
/**
* Get a Redis object with a connection suitable for fetching the specified key
* @param string $key
* @return array (server, RedisConnRef) or (false, false)
*/
protected function getConnection($key)
{
$candidates = array_keys($this->serverTagMap);
if (count($this->servers) > 1) {
ArrayUtils::consistentHashSort($candidates, $key, '/');
if (!$this->automaticFailover) {
$candidates = array_slice($candidates, 0, 1);
}
}
foreach ($candidates as $tag) {
$server = $this->serverTagMap[$tag];
$conn = $this->redisPool->getConnection($server);
if (!$conn) {
continue;
}
try {
$info = $conn->info();
// Check if this server has an unreachable redis master
if ($info['role'] === 'slave' && $info['master_link_status'] === 'down' && $this->automaticFailover) {
// If the master cannot be reached, fail-over to the next server.
// If masters are in data-center A, and slaves in data-center B,
// this helps avoid the case were fail-over happens in A but not
// to the corresponding server in B (e.g. read/write mismatch).
continue;
}
} catch (RedisException $e) {
// Server is not accepting commands
$this->handleException($conn, $e);
continue;
}
return array($server, $conn);
}
$this->setLastError(BagOStuff::ERR_UNREACHABLE);
return array(false, false);
}
