从两个不同的 Spring 引导应用程序访问相同的 MongoRepository 集合

Question

I am working on two different spring boot services, that will need to access a common MongoRepository collection of Users.

For the sake of simplicity, we have SpringBootApp1: User.java

    @Document(collection = "user")
    public class User {
       @Id
       private String id;
       ....
    }

Then I get the repository as: UserRepository.java

public interface UserRepository extends MongoRepository<User, String> {

}

Now I need another application, SpringBootApp2 that reads the Users. I was planning to do the same in the second service, but then I would have two versions of User object, one defined on each service and both of them trying to read from the same MongoRepository collection. If one User class is modified in one service, the other will not know and they will start being off-sync, on top of having repetition or code on both services.

What would be the best approach in this case?

Answer 1

Why you need SpringBootApp2 to read the User table again? You can expose an API in SpringBootApp1 which will fetch you the desired data by calling from the App2. All your database related operations you can keep in one micro service or one app, and if you need the data from the database just expose methods in App1 and call that from App2.

UPDATE : As you said, App1 does READ-WRITE with the collection and grants access only to authenticated users, and App2 does a simple READ-ONLY activity, in that case, you can use the JPA repo interface in App2 with only the read from collection method implemented. You don't need any setters method for the Entity and no save/update method implemented for your interface. This design is harmless. You are just making a call to the same database from two different services. No harm in that. Anyways you are always making a fresh query to the collection from App2.

Else if you have concerns with this approach as well, and if you dont want to keep multiple DB read logics from different services, then ( I do not know what else functionalities your App1 offers other than DB operations ) I would like to suggest you to create App3 which is only for the sole purpose of DB operations.

In that case:

1. App1 will do security related operations + other services
2. Design App3 which does DB manipulation work, without any direct user credentials or security
3. App1 will perform authentication, and on success call App3 for any DB READ-WRITE work, App3 wont need any security
4. App2 will call App3 for any DB READ operations, App3 wont need any security