Curator Framework implements the principle analysis of the principle of zookeeper distributed coordination
Curator Framework is a senior client framework for realizing Zookeeper distributed coordination.ZooKeeper is an open source distributed coordination service, which provides high availability, consistency and persistent data storage and coordination capabilities for distributed applications.Curator Framework is a enhancement of the Zookeeper client, providing a simpler and more reliable way of use.
Curator Framework provides a series of advanced features, including connecting management, naming space, distributed locks, elections and distributed queues, etc., simplifying the use of developers' use of Zookeeper.Let's analyze the principles of Curator Framework to implement Zookeeper distributed coordination.
1. Connection management: Curator Framework provides an automatic repeat mechanism. When network failure or Zookeeeper cluster changes, the connection to ZooKeeper can be automatically re -established to ensure the availability of the application.Curator uses the re -connection mechanism of the Apache Zookeeper client and combines some additional logic to ensure the stability of the connection.
2. Naming space: Curator Framework supports dividing the Zookeeper data structure into multiple independent naming spaces, and the nodes in each name space have an independent path.This division can help achieve better isolation and organization, so that different applications or modules can independently manage their own data.The API provided by Curator can easily operate the nodes under the name space.
3. Distributed lock: Curator Framework provides a distributed lock implementation to achieve mutually exclusive operations in the distributed environment.Through Curator's Interprocessmutex class, it can easily achieve the acquisition and release of locks and ensure the correctness in a distributed environment.The following is a simple distributed lock for example code:
CuratorFramework client = CuratorFrameworkFactory.newClient("localhost:2181", new RetryNTimes(3, 1000));
client.start();
InterProcessMutex lock = new InterProcessMutex(client, "/mylock");
try {
if (lock.acquire(10, TimeUnit.SECONDS)) {
// Code blocks that require mutual exclusion operation
}
} catch (Exception e) {
// Treatment abnormalities
} finally {
try {
lock.release();
} catch (Exception e) {
// Treatment abnormalities
}
}
4. Election: Curator Framework provides support for distributed elections for the election leader in a distributed environment to perform a certain task.Through the Leaderselector class of Curator, you can achieve a Leader election based on Zookeeper.The following is an example code for a simple leader election:
CuratorFramework client = CuratorFrameworkFactory.newClient("localhost:2181", new RetryNTimes(3, 1000));
client.start();
LeaderSelector selector = new LeaderSelector(client, "/leader", new LeaderSelectorListener() {
@Override
public void takeLeadership(CuratorFramework client) throws Exception {
// The code logic executed when becoming a leader
}
@Override
public void stateChanged(CuratorFramework client, ConnectionState newState) {
// Process logic of state change
}
});
selector.autoRequeue();
selector.start();
5. Distributed queue: Curator Framework also provides support for distributed queues to achieve message transmission and task scheduling in a distributed environment.Through Curator's DistributedQueue class, the Zookeeper -based queue can be easily implemented.The following is an example code of a simple distributed queue:
CuratorFramework client = CuratorFrameworkFactory.newClient("localhost:2181", new RetryNTimes(3, 1000));
client.start();
DistributedQueue<String> queue = new DistributedQueue<>(client, "/myqueue", new BytesQueueSerializer());
try {
queue.offer("message1".getBytes());
String message = new String(queue.take());
// Treat the message
} catch (Exception e) {
// Treatment abnormalities
}
