PHP Connection Zookeeper Instance

1, after the installation successful zookeeper, in the Zookeeper Bin directory has started the corresponding startup script

Start the server

./zkserver.sh Start

Start Client: (* Note: CLI requires Java installation)

zkcli.sh

2, php Example:

class Zookeeperdemo extends Zookeeper {

Public function Watcher ($i, $type, $key) {

Echo "Insider watcher\n";

Watcher gets consumed so we need to set a new one

$this->get ('/test ', array ($this, ' Watcher '));

}

}

$zoo = new zookeeperdemo (' 127.0.0.1:2181 ');

$zoo->get ('/test ', array ($zoo, ' Watcher '));

while ( true ) {

Echo '.' ;

Sleep (2);

}

Assignment of leader and worker tasks:

class Worker extends Zookeeper {

Const CONTAINER = '/cluster ';

protected $acl = array (

Array (

' Perms ' = Zookeeper:: Perm_all,

' Scheme ' = ' world ',

' id ' = ' anyone '));

private $isLeader = false ;

private $znode;

Public function __construct ($host = ", $watcher _CB = null , $recv _timeout = 10000) {

parent :: __construct ($host, $watcher _CB, $recv _timeout);

}

Public Function Register () {

if (! $this->exists ( self:: CONTAINER)) {

$this->create ( self:: CONTAINER, null , $this-ACL);

}

$this->znode = $this->create ( self:: CONTAINER. '/w-',

null ,

$this->acl,

Zookeeper:: Ephemeral | Zookeeper::sequence);

$this-Znode = Str_replace ( self:: CONTAINER. '/', ', $this-Znode);

printf ("I ' m registred as:%s\n", $this-Znode);

$watching = $this->watchprevious ();

if ($watching = = $this Znode) {

printf ("Nobody here, I ' m The leader\n");

$this->setleader ( true );

}

Else {

printf ("I ' m watching%s\n", $watching);

}

}

Public function watchprevious () {

$workers = $this->getchildren ( self:: CONTAINER);

Sort ($workers);

$size = sizeof ($workers);

for ($i = 0; $i < $size; $i + +) {

if ($this, Znode = = $workers [$i]) {

if ($i > 0) {

$this->get ( self:: CONTAINER. '/' . $workers [$i-1], array ($this, ' Watchnode '));

return $workers [$i-1];

}

return $workers [$i];

}

}

throw New Exception (sprintf ("Something went very wrong! I can ' t find myself:%s/%s ",

Self:: CONTAINER,

$this, Znode));

}

Public function watchnode ($i, $type, $name) {

$watching = $this->watchprevious ();

if ($watching = = $this Znode) {

printf ("I ' m The new leader!\n");

$this->setleader ( true );

}

Else {

printf ("Now I ' m watching%s\n", $watching);

}

}

Public function Isleader () {

return $this, Isleader;

}

Public function Setleader ($flag) {

$this-Isleader = $flag;

}

Public function run () {

$this->register ();

while ( true ) {

if ($this->isleader ()) {

$this->doleaderjob ();

}

Else {

$this->doworkerjob ();

}

Sleep (2);

}

}

Public function Doleaderjob () {

Echo "Leading\n";

}

Public function Doworkerjob () {

Echo "Working\n";

}

}

$worker = new worker (' 127.0.0.1:2181 ');

$worker->run ();

You can start 3 PHP processes to see the script running.
Process 1:
[Root@localhost zookeeper]# php-f worker.php
I ' m registred as:w-0000000010
Nobody here, I ' m the leader
Leading
Process 2:
[Daniel.luo@localhost zookeeper]$ php-f worker.php
I ' m registred as:w-0000000011
I ' m watching w-0000000010
Working
Process 3:
[Daniel.luo@localhost zookeeper]$ php-f worker.php
I ' m registred as:w-0000000012
I ' m watching w-0000000011
Working

CTRL + C closes the leader process and discovers that processes 2 and 3 will elect a new leader

