PHP Class Predis\Connection\Cluster\RedisCluster

This connection backend offers smart support for redis-cluster by handling automatic slots map (re)generation upon -MOVED or -ASK responses returned by Redis when redirecting a client to a different node. The cluster can be pre-initialized using only a subset of the actual nodes in the cluster, Predis will do the rest by adjusting the slots map and creating the missing underlying connection instances on the fly. It is possible to pre-associate connections to a slots range with the "slots" parameter in the form "$first-$last". This can greatly reduce runtime node guessing and redirections. It is also possible to ask for the full and updated slots map directly to one of the nodes and optionally enable such a behaviour upon -MOVED redirections. Asking for the cluster configuration to Redis is actually done by issuing a CLUSTER SLOTS command to a random node in the pool.

Author: Daniele Alessandri ([email protected])

Inheritance: implements ClusterInterface, implements IteratorAggregate, implements Countable

Show file Open project: nrk/predis

Public Methods

Method	Description
__construct ( Predis\Connection\FactoryInterface $connections, Predis\Cluster\StrategyInterface $strategy = null )
add ( Predis\Connection\NodeConnectionInterface $connection )
askSlotMap ( Predis\Connection\NodeConnectionInterface $connection = null )	Generates an updated slots map fetching the cluster configuration using the CLUSTER SLOTS command against the specified node or a random one from the pool.
buildSlotMap ( )	Generates the current slots map by guessing the cluster configuration out of the connection parameters of the connections in the pool.
connect ( )
count ( )
disconnect ( )
executeCommand ( Predis\Command\CommandInterface $command )
getClusterStrategy ( ) : Predis\Cluster\StrategyInterface	Returns the underlying command hash strategy used to hash commands by using keys found in their arguments.
getConnectionByCommand ( Predis\Command\CommandInterface $command )
getConnectionById ( $connectionID )
getConnectionBySlot ( integer $slot ) : Predis\Connection\NodeConnectionInterface	Returns the connection currently associated to a given slot.
getConnectionFactory ( ) : Predis\Connection\FactoryInterface	Returns the underlying connection factory used to create new connection instances to Redis nodes indicated by redis-cluster.
getIterator ( )
getSlotMap ( ) : SlotMap	Returns the underlying slot map.
isConnected ( )
readResponse ( Predis\Command\CommandInterface $command )
remove ( Predis\Connection\NodeConnectionInterface $connection )
removeById ( string $connectionID ) : boolean	Removes a connection instance by using its identifier.
setRetryLimit ( integer $retry )	Sets the maximum number of retries for commands upon server failure.
useClusterSlots ( boolean $value )	Enables automatic fetching of the current slots map from one of the nodes using the CLUSTER SLOTS command. This option is enabled by default as asking the current slots map to Redis upon -MOVED responses may reduce overhead by eliminating the trial-and-error nature of the node guessing procedure, mostly when targeting many keys that would end up in a lot of redirections.
writeRequest ( Predis\Command\CommandInterface $command )

Protected Methods

Method	Description
createConnection ( string $connectionID ) : Predis\Connection\NodeConnectionInterface	Creates a new connection instance from the given connection ID.
getRandomConnection ( ) : Predis\Connection\NodeConnectionInterface \| null	Returns a random connection from the pool.
guessNode ( integer $slot ) : string	Guesses the correct node associated to a given slot using a precalculated slots map, falling back to the same logic used by Redis to initialize a cluster (best-effort).
move ( Predis\Connection\NodeConnectionInterface $connection, integer $slot )	Permanently associates the connection instance to a new slot.
onAskResponse ( Predis\Command\CommandInterface $command, string $details ) : mixed	Handles -ASK responses by executing again the command against the node indicated by the Redis response.
onErrorResponse ( Predis\Command\CommandInterface $command, Predis\Response\ErrorInterface $error ) : mixed	Handles -ERR responses returned by Redis.
onMovedResponse ( Predis\Command\CommandInterface $command, string $details ) : mixed	Handles -MOVED responses by executing again the command against the node indicated by the Redis response.

Private Methods

Method	Description
queryClusterNodeForSlotMap ( Predis\Connection\NodeConnectionInterface $connection ) : mixed	Queries the specified node of the cluster to fetch the updated slots map.
retryCommandOnFailure ( Predis\Command\CommandInterface $command, string $method ) : mixed	Ensures that a command is executed one more time on connection failure.

Method Details

__construct() public method

public __construct ( Predis\Connection\FactoryInterface $connections, Predis\Cluster\StrategyInterface $strategy = null )
$connections	Predis\Connection\FactoryInterface	Optional connection factory.
$strategy	Predis\Cluster\StrategyInterface	Optional cluster strategy.

add() public method

public add ( Predis\Connection\NodeConnectionInterface $connection )
$connection	Predis\Connection\NodeConnectionInterface

askSlotMap() public method

Generates an updated slots map fetching the cluster configuration using the CLUSTER SLOTS command against the specified node or a random one from the pool.

public askSlotMap ( Predis\Connection\NodeConnectionInterface $connection = null )
$connection	Predis\Connection\NodeConnectionInterface	Optional connection instance.

buildSlotMap() public method

Generation is based on the same algorithm used by Redis to generate the cluster, so it is most effective when all of the connections supplied on initialization have the "slots" parameter properly set accordingly to the current cluster configuration.

public buildSlotMap ( )

connect() public method

public connect ( )

count() public method

public count ( )

createConnection() protected method

Creates a new connection instance from the given connection ID.

protected createConnection ( string $connectionID ) : Predis\Connection\NodeConnectionInterface
$connectionID	string	Identifier for the connection.
return	Predis\Connection\NodeConnectionInterface

disconnect() public method

public disconnect ( )

executeCommand() public method

public executeCommand ( Predis\Command\CommandInterface $command )
$command	Predis\Command\CommandInterface

getClusterStrategy() public method

Returns the underlying command hash strategy used to hash commands by using keys found in their arguments.

public getClusterStrategy ( ) : Predis\Cluster\StrategyInterface
return	Predis\Cluster\StrategyInterface

getConnectionByCommand() public method

public getConnectionByCommand ( Predis\Command\CommandInterface $command )
$command	Predis\Command\CommandInterface

getConnectionById() public method

public getConnectionById ( $connectionID )

getConnectionBySlot() public method

Returns the connection currently associated to a given slot.

public getConnectionBySlot ( integer $slot ) : Predis\Connection\NodeConnectionInterface
$slot	integer	Slot index.
return	Predis\Connection\NodeConnectionInterface

getConnectionFactory() public method

Returns the underlying connection factory used to create new connection instances to Redis nodes indicated by redis-cluster.

public getConnectionFactory ( ) : Predis\Connection\FactoryInterface
return	Predis\Connection\FactoryInterface

getIterator() public method

public getIterator ( )

getRandomConnection() protected method

Returns a random connection from the pool.

protected getRandomConnection ( ) : Predis\Connection\NodeConnectionInterface \| null
return	Predis\Connection\NodeConnectionInterface \| null

getSlotMap() public method

Returns the underlying slot map.

public getSlotMap ( ) : SlotMap
return	Predis\Cluster\SlotMap

guessNode() protected method

Guesses the correct node associated to a given slot using a precalculated slots map, falling back to the same logic used by Redis to initialize a cluster (best-effort).

protected guessNode ( integer $slot ) : string
$slot	integer	Slot index.
return	string	Connection ID.

isConnected() public method

public isConnected ( )

move() protected method

The connection is added to the connections pool if not yet included.

protected move ( Predis\Connection\NodeConnectionInterface $connection, integer $slot )
$connection	Predis\Connection\NodeConnectionInterface	Connection instance.
$slot	integer	Target slot index.

onAskResponse() protected method

Handles -ASK responses by executing again the command against the node indicated by the Redis response.

protected onAskResponse ( Predis\Command\CommandInterface $command, string $details ) : mixed
$command	Predis\Command\CommandInterface	Command that generated the -ASK response.
$details	string	Parameters of the -ASK response.
return	mixed

onErrorResponse() protected method

Handles -ERR responses returned by Redis.

protected onErrorResponse ( Predis\Command\CommandInterface $command, Predis\Response\ErrorInterface $error ) : mixed
$command	Predis\Command\CommandInterface	Command that generated the -ERR response.
$error	Predis\Response\ErrorInterface	Redis error response object.
return	mixed

onMovedResponse() protected method

Handles -MOVED responses by executing again the command against the node indicated by the Redis response.

protected onMovedResponse ( Predis\Command\CommandInterface $command, string $details ) : mixed
$command	Predis\Command\CommandInterface	Command that generated the -MOVED response.
$details	string	Parameters of the -MOVED response.
return	mixed

readResponse() public method

public readResponse ( Predis\Command\CommandInterface $command )
$command	Predis\Command\CommandInterface

remove() public method

public remove ( Predis\Connection\NodeConnectionInterface $connection )
$connection	Predis\Connection\NodeConnectionInterface

removeById() public method

Removes a connection instance by using its identifier.

public removeById ( string $connectionID ) : boolean
$connectionID	string	Connection identifier.
return	boolean	True if the connection was in the pool.

setRetryLimit() public method

-1 = unlimited retry attempts 0 = no retry attempts (fails immediatly) n = fail only after n retry attempts

public setRetryLimit ( integer $retry )
$retry	integer	Number of retry attempts.

useClusterSlots() public method

The slots map can still be manually fetched using the askSlotMap() method whether or not this option is enabled.

public useClusterSlots ( boolean $value )
$value	boolean	Enable or disable the use of CLUSTER SLOTS.

writeRequest() public method

public writeRequest ( Predis\Command\CommandInterface $command )
$command	Predis\Command\CommandInterface