nodejs mongodb驱动程序在空闲时丢弃连接

Question

nodejs mongodb驱动程序在空闲时断开连接并且不重新连接.

背景

下面的脚本连接到mongodb并在全局变量"db"中存储对数据库的引用

config = require("./config.js");
express = require("express");
mongodb = require("mongodb"); 

db = null;

options = {
  auto_reconnect: true,
  db: {
    w: 1
  }
};

mongodb.MongoClient.connect(config.mongo, options, function(err, database) {

  if (err !== null)
    return console.log(err);

  db = database;
  console.log("successfully connected to mongodb");

  db.on("close", (function() {
    return console.log("Connection to database closed automagically " + arguments);
  }));

  db.on("error", function(err) {
    return console.log("Db error " + err);
  });

  app.listen(port);

  return console.log("listening for connections on " + port);

});

每当我从客户端收到插入请求时,都会调用以下函数:

insert = function(collectionName, object) {
  return db.collection(collectionName).insert(object, {w: 1}, (function(err) {
    return console.log("insert complete with err = " + err);
  }));
};

问题

当服务器在很长一段时间后收到插入请求时,它会无声地失败,或者有时会抛出错误说明 unable to insert object (Error: failed to connect to [host:port])

题

有没有办法防止这种行为？我试图使用auto_reconnect选项并写下1的关注但这些都没有帮助.

谢谢!

Answer 1

解决了！

1. 将 server.socketoptions.keepAlive 设置为 1。只需像这样更新选项对象：

   options = {
     auto_reconnect: true,
     db: {
       w: 1
     },
     server: {
       socketOptions: {
         keepAlive: 1
       }
     }
   };
   

2. 定期对数据库执行 Ping 操作。下面的代码片段正是执行此操作：

   printEventCount = function() {
     db.collection("IOSEvents").count(function(err, numberOfEvents) {
       console.log(new Date() + ": error = " + err + ", number of events = " + numberOfEvents);
       ping();
     });
   };
   
   ping = function() {
     if (config.pingPeriod === 0)
       return;    
     setTimeout(printEventCount, config.pingPeriod);
   };