Example Dockerfile and docker-compose.yml for a node js application with mongo db

docker-compose.yml

version: "3.7"
services:
  app:
    build: ./app
    environment:
      - MONGO_URI=mongodb://mongo:27017/app
    depends_on:
      - "mongo"
    command: ["/bin/wait-for.sh", "mongo:27017", "--", "node", "app.js"]
    ports:
      - "8888:8888"
  mongo:
    image: "mongo:3"
    healthcheck:
      test: "if mongo --eval 'quit(db.runCommand({ ping: 1 }).ok ? 0 : 2)'; then exit 0; fi; exit 1;"
      start_period: 60s
      interval: 60s
      timeout: 15s
      retries: 5

Dockerfile

FROM node:12-alpine
RUN apk add --no-cache tini
RUN apk add --no-cache curl

ADD https://raw.githubusercontent.com/eficode/wait-for/master/wait-for /bin/wait-for.sh
RUN chmod +rx /bin/wait-for.sh

USER node
RUN mkdir -p /home/node/app
WORKDIR /home/node/app

COPY --chown=node:node package*.json ./
ENV NODE_ENV=production
RUN npm ci --only=production

# make sure to .dockerignore all unneeded files
COPY --chown=node:node . .

EXPOSE 8888
HEALTHCHECK --start-period=60s --interval=60s --timeout=15s --retries=5 \
  CMD curl -f http://localhost:8888/ || exit 1

ENTRYPOINT ["/sbin/tini", "--"]
CMD ["node", "app.js"]