我们在Node.js和Redis连接中使用Redis npm模块。
偶尔，我们会遇到以下错误：
message: read ECONNRESET, stack: Error: read ECONNRESET
at exports._errnoException (util.js:1020:11)
at TCP.onread (net.js:568:26)
Redis的设置如下：一个Redis服务器在内部网络中，两个Node.js服务器位于DMZ中，每个服务器均有8个PM2实例。节点服务器与Redis服务器之间有防火墙。
NODE版本-6.11.2，REDIS版本-3.2.9，PM2版本-2.4.6
我们进行了TCP转储(TCP dump)。转储显示了一些RST/ACK数据包。TCP转储
在Node.js中，我们创建了一个单一的Redis连接，并尝试将相同的Redis连接用于所有请求。
const Redis = require('redis');
const Config = require('../../config');
const Logger = require('../helpers/logger');
const redisClient = (function() {
// Start with a fake client so that we have a client that works
// even when Redis server is down
let client = {
get: function(key, callback) {
callback(null, null);
},
setex: function(key, time, value) {
Logger.info('Value:',value);
// Do nothing in particular
}
};
// Attempt to create a new instance of an actual redis client
const redisConfig = Config.get('/redis');
const tempClient = Redis.createClient(redisConfig.port,redisConfig.host, {
//eslint-disable-next-line
// console.log('[redis]','Creating the retry strategy');
retry_strategy: function(options) { //eslint-disable-line
//eslint-disable-next-line
console.log('[redis]','Creating the retry strategy');
if (options.error && options.error.code === 'ECONNREFUSED') {
// End reconnecting on a specific error and flush all commands with
// a individual error
//eslint-disable-next-line
console.log('[redis,error]','Connection refused error');
return new Error('The server refused the connection');
}
if (options.error && options.error.code === 'NR_CLOSED') {
//eslint-disable-next-line
console.log('[redis,error]','Connection closed error');
return new Error('The server closed the connection');
}
if (options.attempt > 5) {
// End reconnecting with built in error
//eslint-disable-next-line
console.log('Exceeded attempts');
return undefined;
}
if (options.total_retry_time > 1000 * 60 * 60) {
// End reconnecting after a specific timeout and flush all commands
// with a individual error
//eslint-disable-next-line
console.log('Retrial time:' + options.total_retry_time);
return 1000;
}
// reconnect after
return Math.min(options.attempt * 100, 3000);
}
});
// Set the "client" variable to the actual redis client instance
// once a connection is established with the Redis server
tempClient.on('ready', () => {
client = tempClient;
});
tempClient.on('error', (error) => {
Logger.info(['redis','error'],'Redis client error:', error);
if (error.code === 'NR_CLOSED') {
tempClient.end();
client = Redis.createClient(redisConfig.port,redisConfig.host, {
retry_strategy: function(options) { //eslint-disable-line
if (options.error && options.error.code === 'NR_CLOSED') {
Logger.info(['redis','error'],'Connection closed error');
return new Error('The server refused the connection');
}
}
});
}
});
/**
* Get a redis client
* @return {Object} client - eventually a proper redis client object
* (if redis is up) or a fake client object (if redis is down)
*/
const getClient = function() {
Logger.info('Getting the client ' + client);
return client;
};
return {
getClient: getClient
};
}());
module.exports = redisClient;
我们想知道导致连接问题的具体原因，以及为什么会出现这种情况，应该采取什么解决措施。