feat(zookeeper): add ability to use passed in zookeeper client

Author: hyperlink

README.md

@@ -23,20 +23,23 @@ const Elector = require('elector')
 
 const elector = new Elector({host: 'localhost:2818'})
 
+// alternatively pass in zookeeper client
+// const elector = new Elector(new zookeeper.createClient('localhost:2818'))
+
 // connects to zookeeper and starts the election process
 elector.connect()
 
 elector.on('leader', function () {
-	console.log('I am the supreme leader worship me!');
+	console.log('I am the supreme leader worship me!')
 })
 
 elector.on('follower', function () {
-	console.log('I am but a lowly follower :(');
+	console.log('I am but a lowly follower :(')
 })
 
 // leave the election and closes zookeeper connection
-elector.leave();
-
+// do this to leave the election quickly
+// elector.disconnect()
 ```
 
 

index.js

@@ -11,14 +11,26 @@ class Elector extends EventEmitter {
     super()
     this.id = null
     this.electionPath = electionPath
-    this.client = zookeeper.createClient(zkOptions.host)
+
+    if (this._isZkClient(zkOptions)) {
+      this.client = zkOptions
+    } else {
+      this.client = zookeeper.createClient(zkOptions.host)
+      this.ownsClient = true
+    }
     this.client.once('connected', () => this._onConnect())
   }
 
   connect () {
     this.client.connect()
   }
 
+  _isZkClient (client) {
+    return (
+      _.isObject(client) && 'connectionManager' in client && 'close' in client
+    )
+  }
+
   _onConnect () {
     debug('connected!')
     async.waterfall(
@@ -106,7 +118,9 @@ class Elector extends EventEmitter {
     debug('disconnecting')
     this.disconnecting = true
     this.client.remove(`${this.electionPath}/${this.id}`, error => {
-      this.client.close()
+      if (this.ownsClient) {
+        this.client.close()
+      }
       if (error) {
         return debug(error)
       }

package.json

@@ -5,7 +5,7 @@
   "main": "index.js",
   "scripts": {
     "test": "standard && docker-compose up -d && mocha",
-    "format": "prettier-standard '*.js'",
+    "format": "prettier-standard '*.js' 'test/*js'",
     "semantic-release": "semantic-release pre && npm publish && semantic-release post"
   },
   "repository": {
@@ -42,7 +42,7 @@
   },
   "lint-staged": {
     "linters": {
-      "src/**/*.js": [
+      "**/*.js": [
         "prettier-standard",
         "git add"
       ]

test/index.js

@@ -6,6 +6,8 @@ const Elector = require('../')
 const async = require('async')
 const _ = require('lodash')
 const assert = require('assert')
+const uuid = require('uuid')
+const zookeeper = require('node-zookeeper-client')
 
 describe('Elector', function () {
   let electors = []
@@ -24,34 +26,58 @@ describe('Elector', function () {
     const leaders = []
     const followers = []
 
-    async.each(
-      electors,
-      function (elector, callback) {
-        elector.connect()
-        function cb (error) {
-          if (error) {
-            return callback(error)
-          }
-          if (this.isLeader) {
-            leaders.push(this.id)
-          } else {
-            followers.push(this.id)
-          }
-          callback(null)
-        }
-        elector.on('leader', cb)
-        elector.on('follower', cb)
-        elector.on('error', callback)
-      },
-      function (error) {
-        assert.equal(leaders.length, 1)
-        assert.equal(followers.length, 4)
-        done(error)
+    connectAndListen(electors, leaders, followers, function (error) {
+      assert.equal(leaders.length, 1)
+      assert.equal(followers.length, 4)
+      done(error)
+    })
+  })
+
+  it('should take an existing zookeeper client', function (done) {
+    const electionPath = '/' + uuid.v4()
+    electors = _.times(5, function () {
+      const client = zookeeper.createClient('localhost:2181')
+      return new Elector(client, electionPath)
+    })
+
+    const leaders = []
+    const followers = []
+
+    connectAndListen(electors, leaders, followers, function (error) {
+      assert.equal(leaders.length, 1)
+      assert.equal(followers.length, 4)
+      for (let elector of electors) {
+        assert.equal(elector.ownsClient, undefined)
       }
-    )
+      done(error)
+    })
   })
 })
 
+function connectAndListen (electors, leaders, followers, callback) {
+  async.each(
+    electors,
+    function (elector, callback) {
+      elector.connect()
+      function cb (error) {
+        if (error) {
+          return callback(error)
+        }
+        if (this.isLeader) {
+          leaders.push(this.id)
+        } else {
+          followers.push(this.id)
+        }
+        callback(null)
+      }
+      elector.on('leader', cb)
+      elector.on('follower', cb)
+      elector.on('error', callback)
+    },
+    callback
+  )
+}
+
 function createElector () {
   return new Elector({ host: 'localhost:2181' })
 }