connecting to local mongodb from docker container

Question

I have a local mongoDB server running on mongodb://127.0.0.1:27017. My DB name is localv2. I have a node/express app with the Dockerfile as follows:

FROM node:7.5

RUN npm install -g pm2

RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

COPY package.json /usr/src/app
RUN npm install

COPY . /usr/src/app

EXPOSE 3002

ENV NODE_ENV local

CMD pm2 start --no-daemon server.js

The server.js file has a connection to local mongodb with the following code:

app.db = mongoose.connect("mongodb://127.0.0.1:27017/localv2", options);

This doesn't work when I spin up a container from the image created using the Dockerfile above. I read somewhere that Docker creates a VLAN with a gatway IP address of its own. When I docker inspect my container, my gateway IP address: 172.17.0.1.

Even on changing the mongodb connection to

app.db = mongoose.connect("mongodb://172.17.0.1:27017/localv2", options)

and re-building the image and starting a new container, I still get the error:

MongoError: failed to connect to server [172.17.0.1:27017] on first connect [MongoError: connect ECONNREFUSED 172.17.0.1:27017]

Command to run the container: docker run -p 3002:3002 image-name

Please help.

try found out your PC local IP address not a container adress and add it to the mongo connection config — bxN5

airpower44 airpower44 · Accepted Answer · 2018-07-11T19:19:38

On Docker for Mac, you can use host.docker.internal if your mongo is running on your localhost. You could have your code read in an env variable for the mongo host and set it in the Dockerfile like so:

ENV MONGO_HOST "host.docker.internal"

See here for more details on https://docs.docker.com/docker-for-mac/networking/#use-cases-and-workarounds

connecting to local mongodb from docker container

3 Answers