Zookeeper Leader Election

A simple event based leader election utility.

Installation

npm i zookeeper-leader-election

Usage

const {ClientEvents, ZookeeperLeaderElection}  = require("zookeeper-leader-election");

const opts = {
    host: "localhost:2181",
    zNodeName: "/connect-election",
    childrenPrefix: "guid-n_",
};

const client = new ZookeeperLeaderElection(opts)
    .on(ClientEvents.CHILD_CREATED, ({path, isLeader, id}) => { console.log(`[Child Created], path: ${path}, isLeader: ${isLeader}, id: ${id}`)})
    .on(ClientEvents.CLIENT_CONNECTED, ({host}) => { console.log(`[Client Connected], host: ${host}`)})
    .on(ClientEvents.CLIENT_DISCONNECTED, ({host, path, id}) => { console.log(`[Client Disconnected], host: ${host}, path: ${path}, id: ${id}`)})
    .on(ClientEvents.ERROR, error => { console.error(`[Error], ${JSON.stringify(error)}`)})
    .on(ClientEvents.LEADER_CHANGED, ({path, isLeader, id}) => { console.log(`[Leader Changed], path: ${path}, isLeader: ${isLeader}, id: ${id}`)})
    .on(ClientEvents.NODE_CHILDREN_CHANGED, ({path, isLeader, id}) => { console.log(`[Node Children Changed], path: ${path}, isLeader: ${isLeader}, id: ${id}`)})
    .on(ClientEvents.NODE_CREATED, ({path}) => { console.log(`[Client Created], path: ${path}`)})
    .on(ClientEvents.NODE_REMOVED, ({path, isLeader, id}) => { console.log(`[Node Removed], path: ${path}, isLeader: ${isLeader}, id: ${id}`)});

client.init();

Events

• CHILD_CREATED: is triggered whether the current client instance has been created
• CLIENT_CONNECTED: is triggered when the current client instance connects to Zookeeper
• CLIENT_DISCONNECTED: is triggered when the current client instance disconnects from Zookeeper,
• ERROR: is triggered when a generic error has been issued
• LEADER_CHANGED: is triggered whether the current client leader status changes
• NODE_CHILDREN_CHANGED: is triggered whether the sequence of clients associated to the current zNode changes
• NODE_CREATED: is triggered when the zNode which the current client would attach to has been created
• NODE_REMOVED: is triggered when the zNode attached to the current client has been removed

License

ISC