503 error code for Springboot container connecting to mongo container using docker-compose

Question

I am trying to connect my spring-boot application(REST endpoints) running in a Tomcat container with a mongo container. I am using docker-compose to link both the containers. The application was working perfectly fine. It just stopped working suddenly.

Following is my code:

Dockerfile:

FROM tomcat:9.0.13
WORKDIR /usr/local/tomcat/webapps
#COPY pom.xml .
#RUN ["mvn", "clean", "install"]
COPY /target/TestProfileManager.war .

docker-compose.yml:

version: '3'
services:
 app:
  container_name: VF-BACKEND
  restart: always
  build: .
  ports:
   - "8083:8080" #VF Webservice
  depends_on:
   - mongo
  links:
   - mongo
 mongo:
  container_name: VF-MONGO
  image: mongo:4.0.2
  ports:
   - "27018:27017"
  volumes:
   - /data/vfdb:/data/db

application.properties

spring.data.mongodb.uri=mongodb://mongo:27018/tsp

If I run the application from the IDE as a standalone application, the endpoints do return the response. Only during container communication, I am getting 503. I could not find any post that answers my question.

Thanks for the help. Since, the code was working before, not pasting the classes. Let me know if I should share them as well.

Answer 1

It should be mongodb://mongo:27017 , in service to service communication you do not need to use publish port.

It is important to note the distinction between HOST_PORT and CONTAINER_PORT . the HOST_PORT is 27018 and the container port is 27017 . Networked service-to-service communication use the CONTAINER_PORT

compose-networking