Is it possible for another service module to import another repository module?

[JuTiger-Lee]

Hello
If User Service import to use Feed Repository, Is case no problem?
If there is a problem in this case, Is there any problem if I create an interface in FeedRepository and DIP it?
I think it is correct to use import between services.

[Sairyss]

Read modules section. If you import files between modules you create coupling between those modules.
If your project is small that doesn't matter that much. If your project is big and complicated, and you want to follow the architecture described in readme, you have to use message-driven communication and not import things between modules.

[JuTiger-Lee]

Sorry, It seems that the example was lacking.
Thank you answer me.
I will prepare an example.

[Sairyss]

If i understood correctly, and the Feed is a collection of Posts, you don't need a FeedEntity for it, and you don't need a repository. Just a query to get the feed, and it has to be paginated. For example:

@QueryHandler(GetFeedQuery)
export class GetFeedQueryHandler implements IQueryHandler{
  constructor(
    @InjectPool()
    pool: DatabasePool,
  ) {}

  async execute(
    query: GetFeedQuery,
  ): {
      const feed= await this.pool.query(
      SELECT * FROM .......
        LIMIT ${query.limit}
        OFFSET ${query.offset}
    );
    ....

    // return paginated result
    return Ok(
      new Paginated({
        data: records.rows,
        count: records.rowCount,
        limit: query.limit,
        page: query.page,
      }),
    );
  }
}

[vietlait]

I see the case of @JuTiger-Lee seems to be incorrect in terms of business logic.
Normally, if I want to retrieve a list of posts, I would need to handle it within the FeedModule rather than the UserModule.

Could you explain why you need to retrieve a list of posts within the UserModule?

[JuTiger-Lee]

hello.
I just gave an example of a service module calling another repository module. But it seems that examples were lacking.
I'll add an example and share it again.

[vietlait]

I think if you're aiming to follow the aspects mentioned in this repository, you should not have one service calling another repository unless they both belong to the same aggregate.

If not, you will need to adhere to what @Sairyss said: '...and you want to follow the architecture described in the readme, you have to use message-driven communication and not import things between modules.'
Everything will communicate with each other through queries, command buses, or ports.