Node Codis
Node-codis is a codis client running on nodejs, Used to connect to redis cluster services.
Use the node-zookeeper-client library for service discovery.
Use the redis library to connect to the codis proxy service. The ioredis is supported as well.
Getting started
Installation
npm i node-codis -SUsage
const { NodeCodis } = require('node-codis')
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password'
})
nodeCodis.on('connected', (err, client) => {
if (err) {
console.log(err)
return
}
// Expires after 100 seconds
client.SETEX('node-codis:test', 100, 'hello world', NodeCodis.print)
client.GET('node-codis:test', (err, data) => {
console.log(data) // hello world
})
})ioredis
Codis instance with ioredis can be created by NodeIOCodis.
const Codis = require('node-codis')
const nodeCodis = new Codis.NodeIOCodis({
// ...
})
nodeCodis.on('connected',
/**
* @param {Codis.CodisIOClient} client
*/
(err, client) => {
// ...
})Please NOTE that
NodeIOCodisdoesn't have aNodeCodis!
Documentation
Constructor Options
zkServers string required
Comma separated host:port pairs, each represents a ZooKeeper server. You can optionally append a chroot path, then the client would be rooted at the given path. e.g.
'localhost:3000,localhost:3001,localhost:3002'
'localhost:2181,localhost:2182/test'zkCodisProxyDir string required
Node path of codis-proxy on zookeeper. NodeCodis will establish a connection with all codis-proxy in this directory, and then randomly select one as the client. link this:
/zk/codis/db_test_node/proxyIn the
codis2.x, it is usually located at/zk/codis/db_${product_name}/proxy
In the
codis3.x, If the server codis-proxy is configured asjodis_compatible = false, it is usually located at/jodis/${product_name}/proxy
codisPassword string optional
Login password for codis-proxy.
zkClientOpts object optional
An object to set the zookeeper client options. Currently available options are:
-
sessionTimeoutSession timeout in milliseconds, defaults to 30 seconds. -
spinDelayThe delay (in milliseconds) between each connection attempts. -
retriesThe number of retry attempts for connection loss exception.
Defaults options:
{
sessionTimeout: 30000,
spinDelay: 1000,
retries: 1
}For example:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password',
zkClientOpts: {
sessionTimeout: 10000
}
})redisClientOpts object optional
We use redis to connect to the codis-proxy service, so you can pass in these parameters when redis creates the client.
Reference here https://github.com/NodeRedis/node_redis#rediscreateclient
log boolean | Function
Whether to enable the log, default open, use the debug library. The printed log looks like this:
node-codis Connect to codis at proxy:e203bf77d1c7b3e2c132984f14827c04 @192.168.3.62:19201 +0ms
node-codis Connect to codis at proxy:40297cde8c3453714459ab1c452c6c56 @192.168.3.72:19201 +7ms
You can also set up a custom logger, like this:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password',
log: console.log
})You can pass false to close log.
proxyAddrKey string optional
Proxy address field. Usually when the codis-proxy is registered to zk, the field of the proxy address is called addr. If not, you can pass in a custom field. link this:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password',
proxyAddrKey: 'proxy_addr'
})Property
codisClientPool
Return all connected codis client. link this:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password'
})
console.log(nodeCodis.codisClientPool)Event
connected
When all codis-proxy are connected for the first time, the connect event is fired and a connected codis client is randomly selected as the argument to the callback function. link this:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password'
})
nodeCodis.on('connected', (err, client) => {
if (err) {
console.log(err)
return
}
// Expires after 100 seconds
client.SETEX('node-codis:test', 100, 'hello world', NodeCodis.print)
client.GET('node-codis:test', (err, data) => {
console.log(data) // hello world
})
})reconnected
When the zookeeper node of codis changes, the codis-proxy is reconnected internally, and the reconnected event is triggered, and a random connected codis client is passed to the callback function. link this:
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password'
})
nodeCodis.on('reconnected', (err, client) => {
if (err) {
console.log(err)
return
}
console.log(client)
})Static methods
getRandomClient(clientsMap: CodisClientPool)
Randomly get a connected codis client, if the client pool is empty, return null.
You can use this method in some framework middleware to achieve load balancing. link this:
// app.js
var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var { NodeCodis } = require('node-codis')
var indexRouter = require('./routes/index');
var app = express();
app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));
const nodeCodis = new NodeCodis({
zkServers: '127.0.0.1:6701, 127.0.0.1:6702',
zkCodisProxyDir: '/zk/codis/db_test_node/proxy',
codisPassword: 'your_codis_password'
})
nodeCodis.on('connected', (err, client) => {
if (err) {
console.log(err)
return
}
app.set('codisClientPool', nodeCodis.codisClientPool)
})
app.use(function(req, res, next) {
var codisClientPool = req.app.get('codisClientPool')
req.codisClientPool = NodeCodis.getRandomClient(codisClientPool)
next()
})
app.use('/', indexRouter);
app.use(function (req, res, next) {
next(createError(404));
});
app.use(function (err, req, res, next) {
res.locals.message = err.message;
res.locals.error = req.app.get('env') === 'development' ? err : {};
res.status(err.status || 500);
res.render('error');
});
module.exports = app;// routes/index.js
var express = require('express');
var router = express.Router();
router.get('/test', function (req, res) {
const codisClient = req.codisClient
if (codisClient) {
console.log(codisClient.address)
}
})
module.exports = router;When you always request localhost:3000/test, printed as follows:
192.168.3.72:19201
GET /test - - ms - -
192.168.3.72:19201
GET /test - - ms - -
192.168.3.62:19201
GET /test - - ms - -
192.168.3.62:19201
GET /test - - ms - -
192.168.3.72:19201
GET /test - - ms - -
192.168.3.62:19201
GET /test - - ms - -
192.168.3.62:19201
GET /test - - ms - -
192.168.3.62:19201
GET /test - - ms - -
192.168.3.72:19201
GET /test - - ms - -
192.168.3.62:19201Licence
NodeCodis is licensed under the MIT License - see the LICENSE file for details.