javascript - node.js 中的 Redis 错误

Question

我在 Node.js 中使用 Redis，当部署在实时服务器上时，它开始崩溃并显示以下错误消息:

每秒的请求数更多。

at Object.replyToObject [as reply_to_object] (/home/ubuntu/webservices/node_modules/redis/lib/utils.js:7:15)
at RedisClient.handle_reply (/home/ubuntu/webservices/node_modules/redis/index.js:319:23)
at multi_callback (/home/ubuntu/webservices/node_modules/redis/lib/multi.js:79:43)
at Command.callback (/home/ubuntu/webservices/node_modules/redis/lib/multi.js:116:9)
at normal_reply (/home/ubuntu/webservices/node_modules/redis/index.js:726:21)
at RedisClient.return_reply (/home/ubuntu/webservices/node_modules/redis/index.js:824:9)
at JavascriptRedisParser.returnReply (/home/ubuntu/webservices/node_modules/redis/index.js:192:18)
at JavascriptRedisParser.execute (/home/ubuntu/webservices/node_modules/redis/node_modules/redis-parser/lib/parser.js:553:10)
Socket.<anonymous> (/home/ubuntu/webservices/node_modules/redis/index.js:274:27)
emitOne (events.js:116:13)
Socket.emit (events.js:211:7)
addChunk (_stream_readable.js:263:12)
readableAddChunk (_stream_readable.js:250:11)
at Socket.Readable.push (_stream_readable.js:208:10)
at TCP.onread (net.js:594:20)

我已经编写了通用代码来打开和关闭 Redis 连接并尝试重用连接。 (不确定重用它是否正确)。

我正在使用 Redis“^2.7.1”并在 Ubuntu 上本地安装了 Redis。

我能够进入 Redis 控制台并查看存储的 key 。但不确定为什么它会非常频繁地给出上述错误信息。我正在使用 pm2 模块，因此它会在崩溃后重新启动。

以下是 Node.js 中的 Redis 代码

var Promise = require('bluebird');
var Redis = Promise.promisifyAll(require('redis'));

// Global (Avoids Duplicate Connections)
var redisClient = null;
var redisMultiClient = null;

// Make the below functions as private
function openRedisConnection() {
    if (redisClient && redisClient.connected)
        return redisClient;

    if (redisClient)
        redisClient.end(); // End and open once more

    redisClient = Redis.createClient(6379,process.env.REDIS_URL);
    redisClient.selected_db = 1;
    return redisClient;
}

function openMultiRedisConnection() {
    if (redisMultiClient && redisMultiClient._client.connected) {
        redisMultiClient._client.selected_db = 0;
        return redisMultiClient;
    }

    if (redisMultiClient)
        redisMultiClient.quit(); // End and open once more

    redisMultiClient = Redis.createClient(6379,process.env.REDIS_URL).multi();
    redisMultiClient._client.selected_db = 0;
    return redisMultiClient;
}

function getExpiryTime(key) {
    return 120; // testing
}


module.exports = {
    /**
     * Get Key-Value Pair
     */
    getRedisValue: function (keys) {
        return openRedisConnection().mgetAsync(keys);
    },
    /**
     * Set Key-Value Pair
     */
    setRedisValue: function (key, value) {
        return openRedisConnection()
            .setAsync(key, value, 'EX', getExpiryTime(key))
            .then(function (result) {
                return Promise.resolve(result);
            });
    },

    getV2MultiRedisValue: function (keyList) {
        let redisMultiClientObj = openMultiRedisConnection();
        redisMultiClientObj._client.selected_db = 2;

        redisMultiClientObj.hgetallAsync(keyList);

        return redisMultiClientObj.execAsync()
            .then(function (results) {
                return Promise.resolve(results);
            });
    },

    setV2MultiRedisValue: function (key, redisList) {
        let expiryTime = getExpiryTime(key);
        let redisMultiClientObj = openMultiRedisConnection();
        redisMultiClientObj._client.selected_db = 2;

        for (let item of redisList) {
            redisMultiClientObj.hmsetAsync(item.key, item.value);
            redisMultiClientObj.expireAsync(item.key, expiryTime);
        }
        return redisMultiClientObj.execAsync()
        .then(function (results) {
            return Promise.resolve(results);
        });
    }
};

Answer 1

client.multi([commands]) 不打开多连接，只是指出因为函数 openMultiRedisConnection 具有误导性。

根据引用，你使用了很多错误

client.multi([commands])

MULTI commands are queued up until an EXEC is issued, and then all commands are run atomically by Redis. The interface in node_redis is to return an individual Multi object by calling client.multi(). If any command fails to queue, all commands are rolled back and none is going to be executed (For further information look at transactions).

Multi 返回一个单独的对象，在调用.exec 后再次使用它不是很好。

我不知道为什么您需要一个数据库，但您正在使用 selected_db 和全局客户端变量更改数据库，这很糟糕!并可能导致很多问题!(数据不一致，冲突等)。您可以使用 client.select(callback) 来更改数据库，但这似乎又不是一个好主意。

这部分代码没有理由与不这样做完全一样。

 .then(function (result) {
    return Promise.resolve(result);
  });

只有一个数据库应该没问题。

   var Promise = require('bluebird');
var Redis = Promise.promisifyAll(require('redis'));

// Global (Avoids Duplicate Connections)
var redisClient = [];


// Make the below functions as private
function openRedisConnection( {
    if (redisClient && redisClient.connected)
        return redisClient;

    if (redisClient)
        redisClient.end(); // End and open once more

    redisClient = Redis.createClient(6379,process.env.REDIS_URL,{"db":1});

    return redisClient;
}


function getExpiryTime(key) {
    return 120; // testing
}


module.exports = {
    /**
     * Get Key-Value Pair
     */
    getRedisValue: function (keys) {
        return openRedisConnection().mgetAsync(keys);
    },
    /**
     * Set Key-Value Pair
     */
    setRedisValue: function (key, value) {
        return openRedisConnection()
            .setAsync(key, value, 'EX', getExpiryTime(key));

    },

    getV2MultiRedisValue: function (keyList) {

         let redisClient = openRedisConnection();

        //no need to open multi here....
        let multi = redisClient.multi();

        multi.hgetallAsync(keyList);

        return multi.execAsync();

    },

    setV2MultiRedisValue: function (key, redisList) {
        let expiryTime = getExpiryTime(key);
        let redisClient = openRedisConnection();

        let multi = redisClient.multi();

        for (let item of redisList) {
            multi.hmsetAsync(item.key, item.value);
            multi.expireAsync(item.key, expiryTime);
        }

        return multi.execAsync();

    }
};