How to connect to a Mongo Standalone ReplicaSet, running in Docker, with Mongoose 6.0.8?

Question

Connecting to a MongoDB (with ReplicaSet) running in Docker worked in 5.13.9 but fails in 6.0.8

docker-compose.yml for the database:

This is the docker-compose.yml file for the Database:

version: '3.9'

services:

  loggerdb:
    image: mongo
    container_name: loggerdb
    command: ["--replSet", "rs0", "--bind_ip_all", ]
    restart: always
    ports:
      - "27017:27017"
    volumes:
      - ./data:/data/db
    environment:
      MONGO_INITDB_DATABASE: logger

networks:
  default:
    external: true
    name: logger-network

As you see, there is no Authentication and the database is listening to 27017 on localhost.

The database is running in the Docker Container:

$ docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED       STATUS       PORTS                                           NAMES
b42adb1e26ec   0bcbeb494bed   "docker-entrypoint.s…"   3 hours ago   Up 3 hours   0.0.0.0:27017->27017/tcp, :::27017->27017/tcp   loggerdb

Code to connect (5.13.9)

The code is in Typescript, and for the version 5.13.9 Mongoose I use the following:

mongoose.connect('mongodb://localhost:27017/logger', { useNewUrlParser: true, useUnifiedTopology: true })
    .then(() => {
        app.listen(PORT, () => {
            console.log(`Listening on ${PORT} for Log Messages`);
        });
    });

It is necessary to specify useNewUrlParser and useUnifiedTopology here, otherwise you'll get an error.

The result is that this is working correctly. The program is connecting to the database and I can write stuff to it.

Code to connect (6.0.8)

The code for 6.0.8 is slightly different:

mongoose.connect('mongodb://localhost:27017/logger?replicaSet=rs0')
    .then(() => {
        app.listen(PORT, () => {
            console.log(`Listening on ${PORT} for Log Messages`);
        });
    });

The useNewUrlParser and useUnifiedTopology are obsolete now, and the docs show you need to specify the ReplicaSet as a param.

The result of connecting with this code to 6.0.8 Mongoose is as follows:

[INFO] 14:33:33 ts-node-dev ver. 1.1.8 (using ts-node ver. 9.1.1, typescript ver. 4.3.5)
MongooseServerSelectionError: getaddrinfo ENOTFOUND b42adb1e26ec
   [[ Removed the StackTrace ]]
[ERROR] 14:34:05 MongooseServerSelectionError: getaddrinfo ENOTFOUND b42adb1e26ec

Question

What is the correct to connect to a Mongo Standalone ReplicaSet, running in Docker, with Mongoose 6.0.8 ?

Answer 1

I had this exact problem when trying to connect to a single node replica set inside docker from localhost (I was also upgrading mongoose from v5 to v6.)

I solved the issue by changing my connection string from

mongodb://admin:pass@127.0.0.1:27017/testdb

to

mongodb://admin:pass@127.0.0.1:27017/testdb?directConnection=true

It looks like mongoose is forcefully using the docker hostname which would only work if your code was running inside of docker.

directConnection - Specifies whether to force dispatch all operations to the host specified in the connection URI.