Node app cannot connect to mongo image on my ubuntu instance - mongodb

Question

MongoServerSelectionError: getaddrinfo ENOTFOUND mongo
is the error I'm getting when I try to run docker-compose build.
This is my docker-compse.yml file
version: '3'
services:
app:
container_name: node-app
build: .
ports:
- "3000:3000"
restart: always
volumes:
- ./uploads:/app/uploads
links:
- mongo
mongo:
container_name: mongo
image: mongo
volumes:
- ./data:/data/db
ports:
- "27017:27017"
command: mongod
as well as my Dockerfile
# https://docs.docker.com/samples/library/node/
ARG NODE_VERSION=12.10.0
# https://github.com/Yelp/dumb-init/releases
ARG DUMB_INIT_VERSION=1.2.2
# Build container
FROM node:${NODE_VERSION}-alpine AS build
ARG DUMB_INIT_VERSION
WORKDIR /home/node
RUN apk add --no-cache build-base python2 yarn && \
wget -O dumb-init -q https://github.com/Yelp/dumb-init/releases/download/v${DUMB_INIT_VERSION}/dumb-init_${DUMB_INIT_VERSION}_amd64 && \
chmod +x dumb-init
ADD . /home/node
RUN yarn install && yarn build && yarn cache clean
# Runtime container
FROM node:${NODE_VERSION}-alpine
WORKDIR /home/node
COPY --from=build /home/node /home/node
EXPOSE 3000
CMD ["./dumb-init", "yarn", "start"]
My connection string in the code is
mongodb://mongo:27017/{db_name}
When I run docker ps -a, I can clearly that my mongo image is there. I've googled this issue to no extent, and tried ridiculous combinations of connection strings to try and connect to mongo, but does anyone have any supplemental information or debugging advice to overcome this?

Answer 1

The issue is most probably that you start mongod without passing the --bind_ip_all parameter. By default, mongod only binds to 127.0.0.1 as also stated by other SO posts.