JarCastingAkka Dumb DI
If you don't want to commit to full blown DI for your actor system, but you'd still like to be able to easily mock services and non-actor dependencies.
You normally specify your dependencies - module only in your test config.
In a config, if dependency path:
- is not found -> nothing is overriden, and production behaviour is used
- is found, but module is not found -> ActorInitializaitonException is thrown
- is found, and module specified is found -> module is executed and thus can override depenedncies
Installation
libraryDependencies += "com.marekkadek" %% "akka-dumbdi" % "0.0.2"
ActorWithModule
You mix this trait if you want to specify dependancy module equal to deployment path:
akka.actor.dependency {
/some-guy = "com.myproject.MyFakeModule"
/parent/child = "com.myproject.SomeOtherModule"
}
package com.myproject
class MyFakeModule extends ActorModuleConfigurable {
bind[Service](new FakeService)
...
}
Your actor could look like this. The initialize block is executed first.
class SomeGuy extends Actor with ActorWithModule {
val service: Service = module.get[Service]
override protected def initialize(module: ActorModuleConfigurable): Unit = {
module.bind[Service](new NormalService) // <-- this will be overriden in test, as is specified in cfg
}
...
}
You can extract the trait to more specific one, to separate module logic, if you wish:
trait MyModule extends ActorWithModule { self: Actor =>
override protected def initialize(module: ActorModuleConfigurable): Unit = {
module.bind[Service](new NormalService)
}
}
class SomeGuyWithModule extends Actor with MyModule {
val service: Service = module.get[Service]
...
}
ActorWithModuleNamed
If you wish to speficy name yourself, and not derive one from path. Usage is very similar:
akka.actor.dependency {
some-guy = "com.myproject.MyFakeModule"
}
trait HisNamedModule extends ActorWithNamedModule { self: Actor =>
override protected def moduleConfigLocation: String = "some-guy"
override protected def initialize(module: ActorModuleConfigurable): Unit = {
module.bind[Service](new NormalService)
}
}
Same as ActorWithModule, you can as well extract it to custom trait.
Other info
You can't do any more binds outside initialize method (type system won't allow you).
TODO
- documentation: update with snapshot changes
- documentation: module sigleton
- documentation: how to use fakes, mocks, fixtures
- production: non trivial binds (multiple of same type, named, scoped)
- production: nested modules detection
- tests: conditional, smart binds (in objects modules for tests - for mocking, first being different instance than second (for same interface... for example router with three children with same dependency to Service... we want all three different instances of mock)