Node.js Docker容器中的mongodb副本集连接

我已经在3个virtualbox虚拟机中创建了一个mongodb副本集，分别是manasger1、worker1和worker2。每个副本集都有自己的容器。副本集工作正常，我可以登录到服务器：

docker exec -it mongoNode1 bash -c 'mongo -u $MONGO_USER_ADMIN -p $MONGO_PASS_ADMIN --authenticationDatabase "admin"'
MongoDB shell version v3.6.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.6.4
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
    http://docs.mongodb.org/
Questions? Try the support group
    http://groups.google.com/group/mongodb-user
rs1:PRIMARY> use medmart_db
switched to db medmart_db
rs1:PRIMARY> db.providers.findObe()
2018-05-14T17:46:38.844+0000 E QUERY    [thread1] TypeError: db.providers.findObe is not a function :
@(shell):1:1
rs1:PRIMARY> db.providers.findOne()
{
    "_id" : ObjectId("56ddb50c230e405eafaf7781"),
    "provider_id" : 6829973073,

当我运行nodejs应用程序时，它会连接到副本集。问题是，当我为我的应用程序创建一个容器时，我遇到以下异常，我的容器停止运行，我不能再连接到副本集主副本集，而是连接到次副本集

(node:16) UnhandledPromiseRejectionWarning: MongoNetworkError: failed to connect to server [worker2:27017] on first connect [MongoNetworkError: connection 5 to worker2:27017 timed out]
     at Pool.<anonymous> (/home/nupp/app/node_modules/mongoose/node_modules/mongodb-core/lib/topologies/server.js:505:11)
     at Pool.emit (events.js:182:13)
     at Connection.<anonymous> (/home/nupp/app/node_modules/mongoose/node_modules/mongodb-core/lib/connection/pool.js:329:12)
     at Object.onceWrapper (events.js:273:13)
     at Connection.emit (events.js:182:13)
     at Socket.<anonymous> (/home/nupp/app/node_modules/mongoose/node_modules/mongodb-core/lib/connection/connection.js:256:10)
     at Object.onceWrapper (events.js:273:13)
     at Socket.emit (events.js:182:13)
     at Socket._onTimeout (net.js:447:8)
     at ontimeout (timers.js:427:11)
     at tryOnTimeout (timers.js:289:5)
     at listOnTimeout (timers.js:252:5)
     at Timer.processTimers (timers.js:212:10)
 (node:16) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
 (node:16) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

我的配置文件是：

'use strict';
const serverConfig = {
    port: 3000, 
};
const dbConfig = {
  db: 'xxxxxxx',
  user: 'xxxxxx',
  pass: 'xxxxxxx',
  repl: 'rs1',
  servers: (process.env.DB_SERVERS) ? process.env.DB_SERVERS.split(' ') : ['192.168.99.100:27017','192.168.99.101:27017','192.168.99.102:27017'],
};
module.exports = Object.assign({},{dbConfig, serverConfig});

---

因此，有两个步骤可以解决这个问题。首先也是最重要的是，必须更新virtualBox机器上的主机文件，以获得mongodb域的ip地址。为此：

> docker-machine ssh manager1
docker@manager1:~$ sudo vi /etc/hosts
#add the following
192.168.99.100 manager1
192.168.99.101 worker1
192.168.99.102 worker2

对worker1和worker2重复上述步骤。 如果通过添加以下内容，您就可以跳过第二部分。 接下来，如果出现以下错误：

Error: ERROR::providers-service::model::ProviderModel::getProviderById: TypeError: Cannot read property 'wireProtocolHandler' of null
     at cb (/home/nupp/app/src/model/ProviderModel.js:182:13)
     at /home/nupp/app/node_modules/mongoose/lib/model.js:4161:16
     at Immediate.Query.base.findOne.call (/home/nupp/app/node_modules/mongoose/lib/query.js:1529:14)
     at Immediate.<anonymous> (/home/nupp/app/node_modules/mquery/lib/utils.js:119:16)
     at runCallback (timers.js:696:18)
     at tryOnImmediate (timers.js:667:5)
     at processImmediate (timers.js:649:5)

希望我的解决方案能帮助别人。我花了好几天的时间才最终弄明白

Error: ERROR::providers-service::model::ProviderModel::getProviderById: TypeError: Cannot read property 'wireProtocolHandler' of null
     at cb (/home/nupp/app/src/model/ProviderModel.js:182:13)
     at /home/nupp/app/node_modules/mongoose/lib/model.js:4161:16
     at Immediate.Query.base.findOne.call (/home/nupp/app/node_modules/mongoose/lib/query.js:1529:14)
     at Immediate.<anonymous> (/home/nupp/app/node_modules/mquery/lib/utils.js:119:16)
     at runCallback (timers.js:696:18)
     at tryOnImmediate (timers.js:667:5)
     at processImmediate (timers.js:649:5)

mediator.once('boot.ready', () => {
        const options = {};         
        mongoose.connect(getURL(config), options);
        mongoose.connection.on('error', (err) => {  
            mediator.emit('db.error', err);
        });
        mongoose.connection.on('connected', () => { 
            mediator.emit('db.ready', mongoose);
        });
    });