php 连接zookeeper实例
1、安装成功zookeeper后，在zookeeper 的bin目录下有启动相应的启动脚本http://blog.iyunv.com/lz19880318/article/details/
启动Server
./zkServer.sh start
启动client：(*注：cli需要安装java）
zkCli.sh
2、PHP实例：
<?phpclass ZookeeperDemo extends Zookeeper{ public function watcher($i, $type, $key ) { echo "InsiderWatcher\n" ; // Watcher gets consumedso 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);}
leader与worker任务的分配：
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 registredas: %s\n", $this-> znode ); $watching = $this->watchPrevious(); if($watching == $this-> znode ){ printf( "Nobodyhere, 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 thenew leader!\n" ); $this->setLeader( true ); } else { printf( "Now I'mwatching %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();可以启动3个php进程，查看脚本的运行。
进程1：
# php -f worker.php
I'm registred as: w-0000000010
Nobody here, I'm the leader
Leading
进程2：
$ php -f worker.php
I'm registred as: w-0000000011
I'm watching w-0000000010
Working
进程3：
$ php -f worker.php
I'm registred as: w-0000000012
I'm watching w-0000000011
Working
ctrl + c 关闭leader进程后，会发现进程2与3会选举出新的leader
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