DB and compile time dependency injection

[Ronald Cirka]

I am trying to use Slick 3.0 with Macwire. When extending BuiltInComponentsFromContext, I am not able to use

lazy val db = Database.forDataSource(DB.getDataSource())

since DB.getDataSource() requires an implicit application, and the application has not started yet. (passing in the application from BuiltInComponentsFromContext will cause play to hang on load)

I am guessing the new idiomatic to load components is for the component to have a reference to ApplicationLifecycle, instead of Application - for example the NingWSAPI in Play 2.4 uses ApplicationLifecycle. However, none of the DB interfaces appear to have a reference ApplicationLifecycle; the BoneCPPlugin also expects Application, not ApplicationLifecycle. Am I missing something, or is the DB Api not suited for compile time injection?

[Ronald Cirka]

Never mind i figured it out. I needed to mix in the trait DBComponents.

trait DBModule extends DBComponents {
  def dbApi: DBApi
  lazy val connectionPool: ConnectionPool = wire[BoneConnectionPool]
  lazy val db = Database.forDataSource(dbApi.database("default").dataSource)
}

app.conf:
db.default.driver=org.postgresql.Driver
db.default.url=...

[Loic]

I have the same problem, with Anorm, that does not provide Database.forDataSource method.

Do you know how to to instantiate the DB API? I did not find any example to do this.

My application loader is define as : 

class SimpleApplicationLoader extends ApplicationLoader {

  def load(context: Context) = {

    new ApplicationComponents(context).application

  }

}

trait DBModule extends DBComponents with HikariCPComponent {

  def dbApi: DBApi

  //lazy val db = ??

}

class ApplicationComponents(context: Context) extends BuiltInComponentsFromContext(context) with DBComponents {       

  lazy val applicationController = new controllers.Application("test")

  lazy val assets = new controllers.Assets(httpErrorHandler)

  override lazy val router = new Routes(httpErrorHandler, applicationController, assets)

}}

When I'm trying to use the DB with ;

DB.withConnection { implicit connection =>

    // ...

    }

I have this error : 

java.lang.NoSuchMethodException: play.api.db.DBApi.<init>()

Thanks :)

[Loic]

It seems that I just need to remove DB object and create one from the dbApi instead. 

val db = dbApi.database("default")

I don't know why I was thinking DB.withconnection was using the injector under the hood...  :)