How to access the same DB from 2 different spring boot applications

Question

I have 2 spring microservice Applications and want them to access the same DB. But both Applications create a different databases when i run them. The Application.yml files:

Service 1:

server.port: 8002

logging:
  level:
    org:
      springframework:
        jdbc:
          core:
            DEBUG

spring:
  application:
    name: movie
  datasource:
    url: jdbc:h2:mem:movie_service
    driver-class-name: org.h2.Driver
  h2:
    console:
      enabled: true

eureka:
  client:
    serviceUrl:
      defaultZone: ${EUREKA_URI:http://localhost:8001/eureka}
    registryFetchIntervalSeconds: 1
  instance:
    leaseRenewalIntervalInSeconds: 1
    #preferIpAddress: true
eureka.instance.prefer-ip-address: false

Service 2:

server.port: 8003

spring:
  application.name: client
  datasource:
    url: jdbc:h2:mem:movie_service
    driver-class-name: org.h2.Driver
  h2:
    console:
      enabled: true

logging:
  level:
    org:
      springframework:
        jdbc:
          core:
            DEBUG

eureka:
  client:
    serviceUrl:
      defaultZone: ${EUREKA_URI:http://localhost:8001/eureka}
    registryFetchIntervalSeconds: 1
  instance:
    leaseRenewalIntervalInSeconds: 1
    #preferIpAddress: true
eureka.instance.prefer-ip-address: false

I thought by providing the same URL, one service will create the DB and the other one will just use it.

It's not recommended to share database between microservices. See this post : https://stackoverflow.com/questions/43612866/microservices-with-shared-database-using-multiple-orms — Katy, Jul 11 '20 at 18:43

thst · Accepted Answer · 2020-07-11T18:33:40.747

3

H2 is an in memory database, use a database that allows multiple users.

UPDATE:

actually, I was not precise. H2 has a server mode, but you are running the database embedded in your application.

You need the database as a service and then you can connect from your microservice applications to that running database.

As a side note, it is a common antipattern to have different microservices accessing the same database.

The database - if it is shared at all - should only be shared by instances of one microservice component.

edited Jul 11 '20 at 18:33

answered Jul 11 '20 at 18:28

thst

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In my case its ok to have one user. In every Service i create a table with a foreignKey connecting these tables. I just want them to create the tables in the same DB. – Asperator Jul 11 '20 at 18:35
No, from an architectural point, you are breaking the independence of the microservices. It may be ok for your application at this level (play project) but it leads to a macro-service architecture and deployment monoliths to have. You will find yourself selecting tables you don't own and thus building high coupling between your services over the database schema. As a consequence, you will not be able to update services and data models independently. – thst Jul 11 '20 at 18:40
Thank you very much. This makes totally sense. I changed my architecture accordingly. – Asperator Jul 11 '20 at 21:19

How to access the same DB from 2 different spring boot applications

1 Answers1