initializer-generator

A code generator for use with Anvil-KSP that simplifies adding application initializers to the DI graph with a single @ContributesInitializer annotation.

Code generator setup

Before using the generator, make sure Anvil-KSP is already configured in the project.

Then add the required dependencies:

dependencies {
    ksp("ru.pixnews.anvil.ksp.codegen:initializer-generator:0.1")

    implementation("ru.pixnews.anvil.ksp.codegen:initializer-inject:0.1")
}

Project setup

To make use of this generator's output, the project must have injection set up using Dagger multibindings. The configuration might look something like this (using classes from the initializer-inject module).

Create component to collect all initializers into multibinding set:

import ru.pixnews.anvil.ksp.codegen.initializer.inject.AppInitializersScope

@SingleIn(AppInitializersScope::class)
@MergeComponent(
    scope = AppInitializersScope::class,
    dependencies = […],
)
interface AppInitializerComponent {
    fun inject(initializer: GlobalAndroidxStartupAppInitializer)

    @Component.Factory
    fun interface Factory {
        …
    }
}

Module:

import ru.pixnews.anvil.ksp.codegen.initializer.inject.AppInitializersScope
import ru.pixnews.foundation.initializers.AppInitializer
import ru.pixnews.foundation.initializers.AsyncInitializer
import ru.pixnews.foundation.initializers.Initializer

@ContributesTo(AppInitializersScope::class)
@Module
abstract class AppInitializersModule {
    @Multibinds
    abstract fun appInitializers(): DaggerSet<Initializer>

    @Multibinds
    abstract fun appAsyncInitializers(): DaggerSet<AsyncInitializer>

    companion object {
        @Provides
        fun providesAppInitializer(
            initializers: DaggerSet<Initializer>,
            asyncInitializers: DaggerSet<AsyncInitializer>,
            …
        ): AppInitializer {
            // AppInitializer used in GlobalAndroidxStartupAppInitializer (androidx.startup.Initializer)
            // to execute collected initializers
            return AppInitializer(initializers, asyncInitializers, …)
        }
    }
}

Usage

Implement ru.pixnews.foundation.initializers.AsyncInitializer or ru.pixnews.foundation.initializers.Initializer and annotate it with ContributesInitializer to add it to multibinding:

@ContributesInitializer(replaces = [DebugStrictModeInitializerModule::class])
class TestStrictModeInitializer @Inject constructor(plogger: Logger) : Initializer {
    private val logger = logger.withTag("TestStrictModeInitializer")

    override fun init() {
        logger.v { "Setting up StrictMode" }

        StrictMode.setThreadPolicy(
            …
        )
    }
}

The following binding will be generated based on this annotation:

@Module
@ContributesTo(
  AppInitializersScope::class,
  replaces = [DebugStrictModeInitializerModule::class],
)
object TestStrictModeInitializer_InitializerModule {
  @Provides
  @IntoSet
  @Reusable
  fun provideTestStrictModeInitializer(logger: Logger): Initializer = TestStrictModeInitializer(
      logger = logger
  )
}

Packages

ru.pixnews.anvil.ksp.codegen.initializer.generator

jvm