The Zookeeper class

Introduction

Represents ZooKeeper session.

Class synopsis

Zookeeper

class Zookeeper {

/* Methods */

public __construct(string $host = '', callable $watcher_cb = null, int $recv_timeout = 10000)

public bool addAuth(string $scheme, string $cert, callable $completion_cb = null)

public void close()

public void connect(string $host, callable $watcher_cb = null, int $recv_timeout = 10000)

public string create(
    string $path,
    string $value,
    array $acls,
    int $flags = null
)

public bool delete(string $path, int $version = -1)

public array exists(string $path, callable $watcher_cb = null)

public string get(
    string $path,
    callable $watcher_cb = null,
    array &$stat = null,
    int $max_size = 0
)

public array getAcl(string $path)

public array getChildren(string $path, callable $watcher_cb = null)

public int getClientId()

public ZookeeperConfig getConfig()

public int getRecvTimeout()

public int getState()

public bool isRecoverable()

public bool set(
    string $path,
    string $value,
    int $version = -1,
    array &$stat = null
)

public bool setAcl(string $path, int $version, array $acl)

public static bool setDebugLevel(int $logLevel)

public static bool setDeterministicConnOrder(bool $yesOrNo)

public bool setLogStream(resource $stream)

public bool setWatcher(callable $watcher_cb)

/* Constants */

const int PERM_READ = 1;

const int PERM_WRITE = 2;

const int PERM_CREATE = 4;

const int PERM_DELETE = 8;

const int PERM_ADMIN = 16;

const int PERM_ALL = 31;

const int EPHEMERAL = 1;

const int SEQUENCE = 2;

const int LOG_LEVEL_ERROR = 1;

const int LOG_LEVEL_WARN = 2;

const int LOG_LEVEL_INFO = 3;

const int LOG_LEVEL_DEBUG = 4;

const int EXPIRED_SESSION_STATE = -112;

const int AUTH_FAILED_STATE = -113;

const int CONNECTING_STATE = 1;

const int ASSOCIATING_STATE = 2;

const int CONNECTED_STATE = 3;

const int READONLY_STATE = 5;

const int NOTCONNECTED_STATE = 999;

const int CREATED_EVENT = 1;

const int DELETED_EVENT = 2;

const int CHANGED_EVENT = 3;

const int CHILD_EVENT = 4;

const int SESSION_EVENT = -1;

const int NOTWATCHING_EVENT = -2;

const int SYSTEMERROR = -1;

const int RUNTIMEINCONSISTENCY = -2;

const int DATAINCONSISTENCY = -3;

const int CONNECTIONLOSS = -4;

const int MARSHALLINGERROR = -5;

const int UNIMPLEMENTED = -6;

const int OPERATIONTIMEOUT = -7;

const int BADARGUMENTS = -8;

const int INVALIDSTATE = -9;

const int NEWCONFIGNOQUORUM = -13;

const int RECONFIGINPROGRESS = -14;

const int OK = 0;

const int APIERROR = -100;

const int NONODE = -101;

const int NOAUTH = -102;

const int BADVERSION = -103;

const int NOCHILDRENFOREPHEMERALS = -108;

const int NODEEXISTS = -110;

const int NOTEMPTY = -111;

const int SESSIONEXPIRED = -112;

const int INVALIDCALLBACK = -113;

const int INVALIDACL = -114;

const int AUTHFAILED = -115;

const int CLOSING = -116;

const int NOTHING = -117;

const int SESSIONMOVED = -118;

const int NOTREADONLY = -119;

const int EPHEMERALONLOCALSESSION = -120;

const int NOWATCHER = -121;

const int RECONFIGDISABLED = -122;

}

Predefined Constants

ZooKeeper Permissions

Zookeeper::PERM_READ: Can read nodes value and list its children
Zookeeper::PERM_WRITE: Can set the nodes value
Zookeeper::PERM_CREATE: Can create children
Zookeeper::PERM_DELETE: Can delete children
Zookeeper::PERM_ADMIN: Can execute set_acl()
Zookeeper::PERM_ALL: All of the above flags ORd together

ZooKeeper Create Flags

Zookeeper::EPHEMERAL: If Zookeeper::EPHEMERAL flag is set, the node will automatically get removed if the client session goes away.
Zookeeper::SEQUENCE: If the Zookeeper::SEQUENCE flag is set, a unique monotonically increasing sequence number is appended to the path name. The sequence number is always fixed length of 10 digits, 0 padded.

ZooKeeper Log Levels

Zookeeper::LOG_LEVEL_ERROR: Outputs only error mesages
Zookeeper::LOG_LEVEL_WARN: Outputs errors/warnings
Zookeeper::LOG_LEVEL_INFO: Outputs big action messages besides errors/warnings
Zookeeper::LOG_LEVEL_DEBUG: Outputs all

ZooKeeper States

Zookeeper::EXPIRED_SESSION_STATE: Connected but session expired
Zookeeper::AUTH_FAILED_STATE: Connected but auth failed
Zookeeper::CONNECTING_STATE: Connecting
Zookeeper::ASSOCIATING_STATE: Associating
Zookeeper::CONNECTED_STATE: Connected
Zookeeper::READONLY_STATE: TODO: help us improve this extension.
Zookeeper::NOTCONNECTED_STATE: Connection failed

ZooKeeper Watch Types

Zookeeper::CREATED_EVENT

A node has been created

This is only generated by watches on non-existent nodes. These watches are set using Zookeeper::exists.

Zookeeper::DELETED_EVENT

A node has been deleted

This is only generated by watches on nodes. These watches are set using Zookeeper::exists and Zookeeper::get.

Zookeeper::CHANGED_EVENT

A node has changed

This is only generated by watches on nodes. These watches are set using Zookeeper::exists and Zookeeper::get.

Zookeeper::CHILD_EVENT

A change as occurred in the list of children

This is only generated by watches on the child list of a node. These watches are set using Zookeeper::getChildren.

Zookeeper::SESSION_EVENT

A session has been lost

This is generated when a client loses contact or reconnects with a server.

Zookeeper::NOTWATCHING_EVENT

A watch has been removed

This is generated when the server for some reason, probably a resource constraint, will no longer watch a node for a client.

ZooKeeper System and Server-side Errors

Zookeeper::SYSTEMERROR

This is never thrown by the server, it shouldn't be used other than to indicate a range. Specifically error codes greater than this value, but lesser than Zookeeper::APIERROR, are system errors.

Zookeeper::RUNTIMEINCONSISTENCY

A runtime inconsistency was found.

Zookeeper::DATAINCONSISTENCY

A data inconsistency was found.

Zookeeper::CONNECTIONLOSS

Connection to the server has been lost.

Zookeeper::MARSHALLINGERROR

Error while marshalling or unmarshalling data.

Zookeeper::UNIMPLEMENTED

Operation is unimplemented.

Zookeeper::OPERATIONTIMEOUT

Operation timeout.

Zookeeper::BADARGUMENTS

Invalid arguments.

Zookeeper::INVALIDSTATE

Invalid zhandle state.

Zookeeper::NEWCONFIGNOQUORUM

No quorum of new config is connected and up-to-date with the leader of last committed config - try invoking reconfiguration after new servers are connected and synced.

Available as of ZooKeeper 3.5.0

Zookeeper::RECONFIGINPROGRESS

Reconfiguration requested while another reconfiguration is currently in progress. This is currently not supported. Please retry.

Available as of ZooKeeper 3.5.0

ZooKeeper API Errors

Zookeeper::OK: Everything is OK.
Zookeeper::APIERROR: This is never thrown by the server, it shouldn't be used other than to indicate a range. Specifically error codes greater than this value are API errors (while values less than this indicate a Zookeeper::SYSTEMERROR).
Zookeeper::NONODE: Node does not exist.
Zookeeper::NOAUTH: Not authenticated.
Zookeeper::BADVERSION: Version conflict.
Zookeeper::NOCHILDRENFOREPHEMERALS: Ephemeral nodes may not have children.
Zookeeper::NODEEXISTS: The node already exists.
Zookeeper::NOTEMPTY: The node has children.
Zookeeper::SESSIONEXPIRED: The session has been expired by the server.
Zookeeper::INVALIDCALLBACK: Invalid callback specified.
Zookeeper::INVALIDACL: Invalid ACL specified.
Zookeeper::AUTHFAILED: Client authentication failed.
Zookeeper::CLOSING: ZooKeeper is closing.
Zookeeper::NOTHING: (not error) No server responses to process.
Zookeeper::SESSIONMOVED: Session moved to another server, so operation is ignored.
Zookeeper::NOTREADONLY: State-changing request is passed to read-only server.
Zookeeper::EPHEMERALONLOCALSESSION: Attempt to create ephemeral node on a local session.
Zookeeper::NOWATCHER: The watcher couldn't be found.
Zookeeper::RECONFIGDISABLED: Attempts to perform a reconfiguration operation when reconfiguration feature is disabled.

Table of Contents

Zookeeper::addAuth — Specify application credentials
Zookeeper::close — Close the zookeeper handle and free up any resources
Zookeeper::connect — Create a handle to used communicate with zookeeper
Zookeeper::__construct — Create a handle to used communicate with zookeeper
Zookeeper::create — Create a node synchronously
Zookeeper::delete — Delete a node in zookeeper synchronously
Zookeeper::exists — Checks the existence of a node in zookeeper synchronously
Zookeeper::get — Gets the data associated with a node synchronously
Zookeeper::getAcl — Gets the acl associated with a node synchronously
Zookeeper::getChildren — Lists the children of a node synchronously
Zookeeper::getClientId — Return the client session id, only valid if the connections is currently connected (ie. last watcher state is ZOO_CONNECTED_STATE)
Zookeeper::getConfig — Get instance of ZookeeperConfig
Zookeeper::getRecvTimeout — Return the timeout for this session, only valid if the connections is currently connected (ie. last watcher state is ZOO_CONNECTED_STATE). This value may change after a server re-connect
Zookeeper::getState — Get the state of the zookeeper connection
Zookeeper::isRecoverable — Checks if the current zookeeper connection state can be recovered
Zookeeper::set — Sets the data associated with a node
Zookeeper::setAcl — Sets the acl associated with a node synchronously
Zookeeper::setDebugLevel — Sets the debugging level for the library
Zookeeper::setDeterministicConnOrder — Enable/disable quorum endpoint order randomization
Zookeeper::setLogStream — Sets the stream to be used by the library for logging
Zookeeper::setWatcher — Set a watcher function