elasticsearch curator

Zookeeper native support through the registration of watcher to do event monitoring, but its use is not particularly convenient, the need for developers to repeatedly register their own watcher, more cumbersome. Curator introduces the cache to monitor the Zookeeper server events. Cache is the packaging of event listening in curator, and its monitoring of events can be approximated as a comparison between a

The curator framework is best used by the most popular zookeeper clients. It has the following three advantages 1 A set of very friendly Operation API; 2. Provide some advanced features (including, but not limited to, the packaging mentioned in the previous article) 3. Easy to test MAVEN relies on the following [HTML] view plain copy print? According to the official document and package structure, you can easily see the

It is said that curator connection mechanism is very good, so in the analysis of curator connection and retry mechanism, I would like to first understand the original zookeeper connection problems.Here is my review of the results of the summary, reproduced please specify the source: Jiq Technical BlogAlthough curator provides a so-called high-level abstraction AP

Reprint: http://www.mamicode.com/info-detail-494364.htmlLabel:Zookeeper native API support through the registration of Watcher for event monitoring, but watcher notification is a one-time, so the development process needs to be repeatedly registered watcher, more cumbersome. Curator introduced the cache to listen for events on the zookeeper server. The cache encapsulates zookeeper event monitoring, automates the process of repeatedly registering monit

The Zookeeper Crud API for the OST has synchronous and asynchronous points, and for asynchronous APIs, the AsyncCallback callback needs to be passed. For getdata,getchildren,exists These three APIs, you can also set watcher. How are these features implemented in curator?In curator, you can get results asynchronously in the following three ways:1.inBackground () +curatorlistener2.inBackground (New Background

Service Discovery With the increasing popularity of micro-services, after the system split, the various service modules between the provider and consumer need to be able to find each other, we call service discovery. In soa/distributed systems, services need to find each other. i.e. a Web service might need to find a caching service, etc. DNS can be used for this but it's nowhere near flexible enough for services, is constantly changing. A Service Discovery system provides a mechanism for:servi

Curator provides three types of caching methods: Path Cache,node cache and tree cache.Path Cachethe Path cache is used to monitor a znode child node . When a child node is added, updated, deleted, the Path cache changes its state, containing the latest child nodes, the data and state of the child nodes . That, as its name indicates, monitors the path.There are four classes involved in actual use: Pathchildrencache Pathchildrencacheevent

In practical application development, when a znode changes we need to be notified and do some follow-up processing, curator recipes provides the path Cache to help us easily implement watch Znode. Path Cache The Path cache monitors changes to Znode sub-nodes, for example: Add,update,delete. A Path Cache is used to watch a znode. Whenever a child is added, updated or removed, the Path Cache would change it state to contain the current set of children ,

Curator Framework client use, please see a blog "Zookeeper client curator framework use". The Curatorframework class has an interface that determines whether a node exists checkexists (), which returns a Org.apache.zookeeper.data.Stat object that has a Ephemeralowner attribute in the object. If the node is a persisted node, the value of Ephemeralowner is 0 if the node is a temporary node, the value of Ephem

. CHARSET)); } client.close (); } catch (Exception e) {e.printstacktrace (); }}). Start (); }}Package Com.collonn.javautilmvn.zookeeper.curator.treecache;import Org.apache.curator.retrypolicy;import Org.apache.curator.framework.curatorframework;import org.apache.curator.framework.CuratorFrameworkFactory; Import Org.apache.curator.retry.exponentialbackoffretry;import Org.apache.zookeeper.data.stat;public class tlclientupdatesub {publi

Org.apache.curator.framework.curatorframework;import org.apache.curator.framework.CuratorFrameworkFactory; Import Org.apache.curator.framework.recipes.leader.leaderselector;import Org.apache.curator.framework.recipes.leader.leaderselectorlistener;import Org.apache.curator.framework.state.connectionstate;import Org.apache.curator.retry.ExponentialBackoffRetry; Import Org.apache.curator.utils.ensurepath;public class LeaderListener4 {public static final String C_path = "/testlea Der "; publi

implementation, that is, the first node is not, that no one acquires a lock, and then you create this node, you get this lock. Remember, this node must be a temporary node.Then, of course, acquiring the lock this operation is a dead loop. Controlled by a static variable Countdownlatch. If Countdownlatch is greater than 0, wait hangs, and when someone else releases, another loop continues, attempting to acquire the lock.Let's release the lock. This node is deleted. Countdownlatch Reset to 1.The

Curator solves many zookeeper client very low-level detail development work, including connection reconnection, repeated registration watcher and nodeexistsexception Anomaly, and so on, has become the Apache top project, is one of the most widely used zookeeper clients in the world, Patrick Hunt (the core submitter of zookeeper code) is a "guava is to Java what curator be to zookeeper" (

(); Stat stat = client.checkexists (). Forpath (Nodelistener.c_path); if (stat! = null) {Client.setdata (). Forpath (NodelistenEr. C_path, "GetBytes" (Nodelistener.charset)); } client.close (); } catch (Exception e) {e.printstacktrace (); }}). Start (); }}Package Com.collonn.javautilmvn.zookeeper.curator.nodecache;import Org.apache.curator.retrypolicy;import Org.apache.curator.framework.curatorframework;import org.apache.cur