PHP はオープンソース Zookeeper 分散調整サービスを実装します

wget https://archive.apache.org/dist/zookeeper/zookeeper-3.4.6/zookeeper-3.4.6.tar.gz
tar -zxf zookeeper-3.4.6.tar.gz
cd zookeeper-3.4.6/src/c

./configure
make
make install

<?php
$zk = new Zookeeper("localhost:2181");
$zk->create("/test", "Hello Zookeeper!");
$value = $zk->get("/test");
echo "Node value: " . $value['value'] . "
";
$zk->delete("/test");
?>

<?php
$zk = new Zookeeper("localhost:2181");
$lock_path = "/test/lock";
$lock = $zk->create($lock_path . "/lock-", null, array(
    array('perms' => Zookeeper::PERM_ALL, 'scheme' => 'world', 'id' => 'anyone')
), Zookeeper::EPHEMERAL | Zookeeper::SEQUENCE);

while (!$zk->exists($lock, null)) {}

$children = $zk->getChildren($lock_path);
sort($children);
$lowest_node = reset($children);

if ($lock == $lock_path . '/' . $lowest_node) {
    echo "I got the lock!
";
    // do something
    $zk->delete($lock);
} else {
    echo "I failed getting the lock!
";
}
?>

<?php
$zk = new Zookeeper("localhost:2181");

function node_change_callback($event_type, $state, $path) {
    global $zk;
    $value = $zk->get($path, node_change_callback);
    echo "Node value changed to: " . $value['value'] . "
";
}

$zk->create("/test", "Hello, world");

$value = $zk->get("/test", node_change_callback);

sleep(10);

$zk->set("/test", "Hello, Zookeeper!");

sleep(10);

$zk->delete("/test");
?>