Magic Modules

Deprecation notice

This project has been deprecated in favor of Gradle's type-safe project dependencies.

What was this?

Read more in the blog post

For large Android projects hosted in mono repos, management for module names might be a real pain, specially when we have lots of moving parts under a structure driven by nested Gradle subprojects.

This experimental plugin attemps to solve that. It parses a project tree like this

.
├── app
│   └── src
│       └── main
│           ├── AndroidManifest.xml
│           ├── java
│           └── res
├── build.gradle
├── buildSrc
│   ├── build.gradle.kts
│   └── src
│       └── main
│           └── kotlin
├── common
│   ├── core
│   │   ├── build.gradle
│   │   └── src
│   │       └── main
│   └── utils
│       ├── build.gradle.kts
│       └── src
│           └── main
├── features
│   ├── home
│   │   ├── build.gradle
│   │   └── src
│   │       └── main
│   └── login
│       ├── build.gradle
│       └── src
│           └── main
|
|
└── settings.gradle

and

• it automatically includes all founded modules in settings.gradle
• it writes 3 Kotlin files under your buildSrc/src/main/kotlin :

JavaModules.kt

// Generated by MagicModules plugin. Mind your Linters!
import kotlin.String
import kotlin.collections.List

object JavaModules {
    const val UTILS: String = ":utils"

    object SomeInnerFolder {
        const val SOME: String = ":some-inner_folder:some"

        val allAvailable: List<String> = 
                    listOf(
                        SOME
                    )
    }

    val allAvailable: List<String> = 
            listOf(
                UTILS
            )
}

LibraryModules.kt

// Generated by MagicModules plugin. Mind your Linters!
import kotlin.String
import kotlin.collections.List

object LibraryModules {
    object Common {
        const val CORE: String = ":common:core"

        object Shared {
            const val FORMATTER: String = ":common:shared:formatter"

            val allAvailable: List<String> = 
                        listOf(
                            FORMATTER
                        )
        }

        val allAvailable: List<String> = 
                    listOf(
                        CORE
                    )
    }

    object Features {
        const val HOME: String = ":features:home"
        const val LOGIN: String = ":features:login"

        val allAvailable: List<String> = 
                    listOf(
                        HOME,
                        LOGIN
                    )
    }
}

ApplicationModules.kt

// Generated by MagicModules plugin. Mind your Linters!
import kotlin.String
import kotlin.collections.List

object ApplicationModules {
    const val APP: String = ":app"

    val allAvailable: List<String> = 
            listOf(
                APP
            )
}

In this way, refactors around the project structure will become a bit easier, since build.gradle configuration

dependencies {
    implementation project(JavaModules.UTILS)
    implementation project(LibraryModules.Common.CORE)
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
    implementation ...
}

will break if common/utils moves around. The new constant under buildSrc will be mapped and will be ready to use.

We can also add all the libraries to an monotlithic-like app easily

dependencies {
    JavaModules.allAvailable.each { implementation project(it) }
    LibraryModules.Common.allAvailable.each { implementation project(it) }
}

Setup

To try this plugin out, you can grab a snapshot build from Jitpack. Add this snippet in your settings.gradle file

buildscript {
    repositories {
        mavenCentral()	
        maven { url 'https://jitpack.io' }
    }

    dependencies {
        classpath 'com.github.dotanuki-labs:magic-modules:<plugin-version>'
    }
}

apply plugin: "io.labs.dotanuki.magicmodules"

and remove all include statements

include 'app'
include 'featureA'
include 'featureB'
include 'featureC'
include ...

They are not needed anymore.

If your project uses a multi-application layout, with standalone apps for your features/screens, you can opt-in to not include all com.android.application modules in order to reduce configuration times locally and eventually build times on CI.

rootProject.name='awesome-project'

apply plugin: "io.labs.dotanuki.magicmodules"

magicModules {
    includeApps = false
}

include ':app'

Matching Gradle build files

This plugin walks your project tree and inspect all the build.gradle and build.gradle.kts files in order to learn if each founded module matches an Android library, a JVM library or an Android application. This means that Magic Modules is sensitive on how you apply plugins in your Gradle build scripts, for instance using

apply plugin: 'com.android.library'

or

plugins {
    kotlin("jvm")
}

This plugin does a best-effort attempt in order to catch all the common cases, but it might not work at all if you

• (1) have some strategy to share build logic accross Gradle modules and
• (2) applied the application or library plugin using such shared build logic for your modules

Building and testing

To build this plugin and publish it locally for testing

./gradlew publishToMavenLocal

To run all the checks, including integration tests

./gradlew ktlintCheck test

To check logs generated by this plugin and learn how this plugin works, we have a sample project available

cd sample
./gradlew clean app:assembleDebug --info | grep MagicModulesPlugin

Limitations

The main limitation I've found with this approach is that - right now - the plugin generates the JavaModules.kt, LibraryModules.kt and ApplicationModules.kt under the main source set of buildSrc, which means eventually issues with linters that run for buildSrc files.

I need more time in order to figure out if we can have such generated files under buildSrc/build somehow.

Further work

I realised that

• It might be useful to configure the output folder/package for JavaModules.kt, LibraryModules.kt and ApplicationModules.kt

Author

Coded by Ubiratan Soares (follow me on Twitter)

Contributors

• Thiago Santos - @programadorthi

License

The MIT License (MIT)

Copyright (c) 2020 Dotanuki Labs

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.