Spring Datasources based on Environment

Question

I am trying to configure my Spring Boot application to use specific datasources when certain environmental variables exist. For example, if the MY_PROD_DATASOURCE environmental variable exists, I would like to use my production datasource; otherwise, I would like to use my local datasource (of the same type).

I have found something in the Spring reference that explains how a single datasource could be declared in my application.properties. Specifically, a MySQL datasource could look like:

spring.datasource.url=jdbc:mysql://localhost/test
spring.datasource.username=dbuser
spring.datasource.password=dbpass
spring.datasource.driverClassName=com.mysql.jdbc.Driver

However, I do not see how I could change the datasource properties conditionally in this file. Is there another way to do it?

Answer 1

In Spring Boot you can:

1. Externalize application.properties from your jar and provide file per environment by adding path as a startup parameter:

   java -jar your-app.jar --spring.config.location=/path/to/app.properties
   

2. Use Spring profiles. Create application-${profile}.properties for each profile, in each one different datasource properties

3. Use Spring profiles and instead of application.properties, put your properties to application.yaml where you can put properties for all environments using convention as below:

   spring:
       profiles: development
   server:
       port: 9001
   
   ---
   
   spring:
       profiles: production
   server:
       port: 0
   

4. Use environment variables and set SPRING_DATASOURCE_URL, SPRING_DATASOURCE_USERNAME, SPRING_DATASOURCE_PASSWORD, and (optionally) SPRING_DATASOURCE_DRIVER_CLASS_NAME.

Learn more in the Spring Boot reference section on How to change configuration depending on the environment and External Configuration.