1

I'm trying to connect my Spring Boot application (using spring-boot-starter-data-mongodb) to a MongoDB instance within a shared Docker network managed by docker-compose.

The connection is failing, and my application appears to be attempting to connect to the default MongoDB address (mongodb://localhost:27017) instead of the host/port I've configured for the Docker network. This suggests my configuration is being ignored or overridden due to Spring Boot's Externalized Configuration precedence.

My Setup

1. docker-compose.yml

YAML

 services: # 1. MongoDB Service mongodb: image: mongo:latest container_name: mongodb ports: # Exposing for external access/testing, but internal communication doesn't use this port mapping - "27017:27017" environment: MONGO_INITDB_ROOT_USERNAME: myuser MONGO_INITDB_ROOT_PASSWORD: mypassword volumes: - mongo_data:/data/db # 2. Spring Boot Application Service myapp: build: . container_name: myapp ports: - "8080:8080" depends_on: - mongodb # --- CRITICAL AREA --- environment: # These properties seem to be failing to correctly configure the connection: SPRING_DATA_MONGODB_HOST: mongodb SPRING_DATA_MONGODB_PORT: 27017 SPRING_DATA_MONGODB_USERNAME: myuser SPRING_DATA_MONGODB_PASSWORD: mypassword SPRING_DATA_MONGODB_DATABASE: mydatabase volumes: mongo_data:

2. Spring Boot application.yaml (or application-prod.yaml)

This is the internal configuration I'm trying to override:

YAML

spring: data: mongodb: host: localhost # This is the value I expect to be overridden port: 27017 database: mydatabase username: myuser password: mypassword

The Problem

  1. My application logs show a connection attempt to mongodb://localhost:27017 or a connection timeout error.

  2. I suspect the environment variables in my docker-compose.yml are either incorrectly formatted for Spring Boot's relaxed binding or not taking effect, allowing the default settings (or the values in application.yaml) to take precedence.

What is the correct and most robust way to configure Spring Boot's MongoDB connection string using the Docker Compose service name, ensuring it correctly overrides any configuration inside my JAR?

I am specifically looking for confirmation on:

  1. The correct environment variable format for the full connection URI (e.g., SPRING_DATA_MONGODB_URI).

  2. Why using SPRING_DATA_MONGODB_HOST: mongodb is failing to override the localhost setting.

Improve this question
2
  • Looks like you are following a tutorial/information using SPring Boot 3 and decided to use Spring BOot 4. Properties are now in the spring.mongodb insteda of spring.data.mongodb namespace. So you are baiscally using the wrong properties. See the migration guides. Commented Nov 26 at 13:29
  • stackoverflow.com/help/gen-ai-policy Commented Nov 26 at 17:49

1 Answer 1

Reset to default
2

Looks like you are following a tutorial/information using Spring Boot 3 and decided to use Spring Boot 4. Properties are now in the spring.mongodb instead of spring.data.mongodb namespace. So you are baiscally using the wrong properties. See the migration guides.

So use spring.mongodb.host instead of spring.data.mongodb.host (and friends).

spring: mongodb: host: localhost # This is the value I expect to be overridden port: 27017 database: mydatabase username: myuser password: mypassword

Then in your Docker compose file

environment: SPRING_MONGODB_HOST: mongodb SPRING_MONGODB_PORT: 27017 SPRING_MONGODB_USERNAME: myuser SPRING_MONGODB_PASSWORD: mypassword SPRING_MONGODB_DATABASE: mydatabase
Improve this answer
Sign up to request clarification or add additional context in comments.

1 Comment

I would also make it a rule of thumb for every major upgrade to run Spring Initializr again so you can compare up to date configuration with what you have. Configuration properties which disappear, not exactly uncommon in Spring Boot Land, stick out more like that.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.