SpringBoot in Docker not connecting to Mongo in Docker

Question

I have a Spring Boot Application and developed it with a mongo db which was running in brew services.

To get a connection to the db I just had to put the following

Answer 1

Try not defining the ports of Mongo.

version: '3'

services:

mongo:
 container_name: docker-mongo
 image: mongo:latest
 volumes:
  - ./data/db:/data/db

spring:
 depends_on:
   - mongo
 image:
   docker-spring-http-alpine
 ports:
   - "8080:8080"
 links:
   - mongo