Scaling your build logic

Presented at Londroid on 2025.01.16

This presentation explores strategies for managing and extracting common build logic across different project phases, from pre-compiled scripts to convention plugins and defining your very own custom DSL to hide away the complexity of third party dependencies and plugins.

Footnotes:
[^1]: This presentation will focus on Gradle as a build tool.
[^2]: https://blog.gradle.org/declarative-gradle#software-definition-vs-build-logic
[^3]: Always consider the stage of the project. Just as to any approach there are always caveats.
[^4]: https://github.com/cdsap/ProjectGenerator
[^5]: https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration
[^6]: https://docs.gradle.org/current/userguide/implementing_gradle_plugins_precompiled.html
[^7]: Unless you use `--no-rebuild`
[^8]: https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:using_buildsrc
[^9]: https://medium.com/proandroiddev/stop-using-gradle-buildsrc-use-composite-builds-instead-3c38ac7a2ab3
[^10]: https://developer.android.com/build/releases/past-releases/agp-8-0-0-release-notes
[^11]: https://developer.android.com/reference/tools/gradle-api/8.0/com/android/build/api/dsl/SettingsExtension
[^12]: https://github.com/anthonymonori/sample-gradle-project/pull/1/files
[^13]: https://developer.squareup.com/blog/herding-elephants/
[^14]: https://github.com/android/nowinandroid
[^15]: https://github.com/slackhq/foundry

Transcript

1. Scaling your build logic Antal Monori, Android Engineer @ Wise
2. Show your hands If you know this little elephant...
3. Disclaimer1 1 This presentation will focus on Gradle as a build tool.
4. Definition build logic (n.)
5. Definition build logic (n.) A set of declarative instructions and plugins that transform source code and resources into deployable packages.
6. Definition build logic (n.) A set of declarative instructions and plugins that transform source code and resources into deployable packages. "Build logic is how the software will be built. It is the code that adds new capabilities, integrates different tools, and supplies conventions to the software definition."2 2 https://blog.gradle.org/declarative-gradle#software-definition-vs-build-logic
7. Goals
8. Goals 1. Some Gradle fundamentals
9. Goals 1. Some Gradle fundamentals 2. How to create a Gradle plugin
10. Goals 1. Some Gradle fundamentals 2. How to create a Gradle plugin 3. Pre-compiled scripts vs convention plugins
11. Goals 1. Some Gradle fundamentals 2. How to create a Gradle plugin 3. Pre-compiled scripts vs convention plugins 4. buildSrc vs includedBuild()
12. Goals 1. Some Gradle fundamentals 2. How to create a Gradle plugin 3. Pre-compiled scripts vs convention plugins 4. buildSrc vs includedBuild() 5. How to build a declarative, custom DSL
13. Let's get started // settings.gradle.kts rootProject.name="sample-gradle-project" pluginManagement { repositories { google() mavenCentral() gradlePluginPortal() } } include (":app")
14. Let's get started // settings.gradle.kts rootProject.name="sample-gradle-project" pluginManagement { repositories { google() mavenCentral() gradlePluginPortal() } } include (":app")
15. Disclaimer3 3 Always consider the stage of the project. Just as to any approach there are always caveats.
16. Let's create a more realistic example4 $ projectGenerator --shape triangle --layers 5 --modules 100 --classes-module-type random --classes-module 150 --language kts --agp-version 8.7.2 --kgp-version 2.1.0 --type-of-string-resources large --generate-unit-test true --gradle 8.11.1 --dependency-plugins true 4 https://github.com/cdsap/ProjectGenerator
17. Let's create a more realistic example4 $ projectGenerator --shape triangle --layers 5 --modules 100 --classes-module-type random --classes-module 150 --language kts --agp-version 8.7.2 --kgp-version 2.1.0 --type-of-string-resources large --generate-unit-test true --gradle 8.11.1 --dependency-plugins true 4 https://github.com/cdsap/ProjectGenerator
18. A more realistic example // settings.gradle.kts rootProject.name="sample-gradle-project" include (":app") include (":layer_0:module_0_1") include (":layer_0:module_0_2") include (":layer_0:module_0_3") include (":layer_0:module_0_4") include (":layer_0:module_0_5") include (":layer_0:module_0_6") include (":layer_0:module_0_7") include (":layer_0:module_0_8") include (":layer_0:module_0_9") include (":layer_0:module_0_10") include (":layer_0:module_0_11") include (":layer_0:module_0_12") include (":layer_0:module_0_13") include (":layer_0:module_0_14") include (":layer_0:module_0_15") include (":layer_0:module_0_16") include (":layer_1:module_1_17") include (":layer_1:module_1_18") include (":layer_1:module_1_19") include (":layer_1:module_1_20") // ...
19. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
20. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
21. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
22. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
23. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
24. With many build scripts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
25. Growing pains This is when the real growing pains start to show their face.
26. Growing pains This is when the real growing pains start to show their face. • Duplication across build scripts
27. Growing pains This is when the real growing pains start to show their face. • Duplication across build scripts • Misconfiguration going unnoticed
28. Growing pains This is when the real growing pains start to show their face. • Duplication across build scripts • Misconfiguration going unnoticed • Larger surface area to maintain
29. Growing pains This is when the real growing pains start to show their face. • Duplication across build scripts • Misconfiguration going unnoticed • Larger surface area to maintain • Tedious and slow iterations/migrations
30. Let's start extracting // layer_1/module_1_20/build.gradle.kts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":", "_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
31. Let's start searching for advice
32. Applying what the internet says // build.gradle.kts subprojects { android { compileSdk = 33 defaultConfig { minSdk = 24 } } }
33. Applying what the internet says // build.gradle.kts subprojects { android { // ERROR: Unresolved reference 'android'. compileSdk = 33 defaultConfig { minSdk = 24 } } }
34. Yes, we can fix this... // build.gradle.kts subprojects { plugins.withId("com.android.application") { configureAndroid(project) } plugins.withId("com.android.library") { configureAndroid(project) } } fun configureAndroid(project: Project) { project.extensions.configure<com.android.build.gradle.BaseExtension>("android") { compileSdkVersion(33) defaultConfig { minSdk = 24 } } }
35. Tip #1 Avoid using allprojects {} and subprojects {} because:
36. Tip #1 Avoid using allprojects {} and subprojects {} because: • Breaks isolation5 5 https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration
37. Tip #1 Avoid using allprojects {} and subprojects {} because: • Breaks isolation5 • Performance hit 5 https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration
38. Tip #1 Avoid using allprojects {} and subprojects {} because: • Breaks isolation5 • Performance hit • Hard to debug 5 https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:convention_plugins_vs_cross_configuration
39. Tip #1 Avoid using allprojects {} and subprojects {} because: • Breaks isolation • Performance hit • Hard to debug Instead Use pre-compiled scripts or convention plugins
40. What are they A pre-compiled script6 refers to a reusable build script file, that encapsulates shared build logic (such as configurations and dependencies) for consistent use across multiple projects. 6 https://docs.gradle.org/current/userguide/implementing_gradle_plugins_precompiled.html
41. What are they A pre-compiled script refers to a reusable build script file, that encapsulates shared build logic (such as configurations and dependencies) for consistent use across multiple projects. A convention plugin refers to a reusable Gradle binary plugin, that encapsulates shared build logic (such as configurations and dependencies) for consistent use across multiple projects.
42. They are the same picture.
43. Are they the same? Both pre-compiled scripts and convention plugins:
44. Are they the same? Both pre-compiled scripts and convention plugins: • Written in Groovy or Kotlin DSL
45. Are they the same? Both pre-compiled scripts and convention plugins: • Written in Groovy or Kotlin DSL • Encapsulate common, shared build logic
46. Are they the same? Both pre-compiled scripts and convention plugins: • Written in Groovy or Kotlin DSL • Encapsulate common, shared build logic • Are simply plugins after all
47. Let's start with pre-compiled scripts
48. Pre-compiled scripts $ mkdir buildSrc $ touch buildSrc/build.gradle.kts // buildSrc/build.gradle.kts plugins { `kotlin-dsl` `kotlin-dsl-precompiled-script-plugins` // Enables Kotlin DSL for precompiled script plugins } dependencies { } repositories { google() mavenCentral() gradlePluginPortal() }
49. Let's take a library build script plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":","_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
50. sample.android.library.gradle.kts plugins { id("com.android.library") id("org.jetbrains.kotlin.android") id("kotlin-kapt") } val normalizedName = name.replace(":","_") android { namespace = "com.example.mylibrary.$normalizedName" compileSdk = 33 defaultConfig { minSdk = 24 testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner" } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies { /* ... */ }
51. The generated code // buildSrc/build/generated-sources/kotlin-dsl-plugins/kotlin/Sample_android_libraryPlugin.kt public class Sample_android_libraryPlugin : org.gradle.api.Plugin<org.gradle.api.Project> { override fun apply(target: org.gradle.api.Project) { try { Class .forName("Sample_android_library_gradle") .getDeclaredConstructor( org.gradle.api.Project::class.java, org.gradle.api.Project::class.java ) .newInstance(target, target) } catch (e: java.lang.reflect.InvocationTargetException) { throw e.targetException } } }
52. Applying the plugin // layer_1/module_1_20/build.gradle.kts plugins { id("sample.android.library") } dependencies { /* ... */ }
53. Successfully extracted build logic Now we just need to apply to all build scripts.
54. What about the root project? // build.gradle.kts plugins { id("org.jetbrains.kotlin.jvm") version("2.1.0") apply false id("com.android.application") version ("8.7.2") apply false id("com.android.library") version ("8.7.2") apply false }
55. sample.root.gradle.kts plugins { }
56. Where to pin them instead? // buildSrc/build.gradle.kts plugins { `kotlin-dsl` `kotlin-dsl-precompiled-script-plugins` } dependencies { implementation("com.android.tools.build:gradle:8.7.2") implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.0") } repositories { google() mavenCentral() gradlePluginPortal() }
57. Applying the plugin // build.gradle.kts plugins { id("sample.android.root") }
58. ✅ All good, right?
59. Tip #2 Avoid using buildSrc:
60. Tip #2 Avoid using buildSrc: • It's a special directory, only one can exist
61. Tip #2 Avoid using buildSrc: • It's a special directory, only one can exist • Added to the root project classpath
62. Tip #2 Avoid using buildSrc: • It's a special directory, only one can exist • Added to the root project classpath • Any change7 causes the whole project to become out-of-date8 8 https://docs.gradle.org/current/userguide/sharing_build_logic_between_subprojects.html#sec:using_buildsrc 7 Unless you use --no-rebuild
63. Tip #2 Avoid using buildSrc: • It's a special directory, only one can exist • Added to the root project classpath • Any change causes the whole project to become out-of-date Instead Use composite builds (also known as includedBuild())9 9 https://medium.com/proandroiddev/stop-using-gradle-buildsrc-use-composite-builds-instead-3c38ac7a2ab3
64. Migrating to composite builds $ mv buildSrc build-logic // settings.gradle.kts rootProject.name="sample-gradle-project" includeBuild ("build-logic") include (":app") include (":layer_0:module_0_1") include (":layer_0:module_0_2") include (":layer_0:module_0_3") include (":layer_0:module_0_4") include (":layer_0:module_0_5") include (":layer_0:module_0_6") include (":layer_0:module_0_7") include (":layer_0:module_0_8") include (":layer_0:module_0_9") // ...
65. ✅ Sync and ready to go
66. Migrating to convention plugins // build-logic/build.gradle.kts plugins { `kotlin-dsl` `kotlin-dsl-precompiled-script-plugins` // Enables Kotlin DSL for precompiled script plugins } dependencies { implementation("com.android.tools.build:gradle:8.7.2") implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.0") } repositories { google() mavenCentral() gradlePluginPortal() }
67. Migrating to convention plugins // build-logic/build.gradle.kts plugins { `kotlin-dsl` } dependencies { implementation("com.android.tools.build:gradle:8.7.2") implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.0") } gradlePlugin { plugins { } } repositories { google() mavenCentral() gradlePluginPortal() }
68. Migrating to convention plugins // build-logic/build.gradle.kts plugins { /* .. */} dependencies { /* .. */} gradlePlugin { plugins { create("root") { id = "sample.$name" implementationClass = "convention.SampleRootPlugin" version = "1.0.0" } create("android.library") { id = "sample.$name" implementationClass = "convention.SampleAndroidLibraryPlugin" version = "1.0.0" } create("android.application") { id = "sample.$name" implementationClass = "convention.SampleAndroidApplicationPlugin" version = "1.0.0" } } } repositories { /* .. */ }
69. Migrating to convention plugins // build-logic/src/main/kotlin/convention/SampleRootPlugin.kt internal class SampleRootPlugin : Plugin<Project> { override fun apply(project: Project) { require(project == project.rootProject) { "Plugin must be applied to root project!" } } }
70. Migrating to convention plugins internal class SampleAndroidApplicationPlugin : Plugin<Project> { override fun apply(project: Project) { with(project) { plugins.apply("com.android.library") plugins.apply("org.jetbrains.kotlin.android") plugins.apply("kotlin-kapt") extensions.getByType(ApplicationExtension::class.java).apply { compileSdk = 33 defaultConfig { applicationId = "com.example.myapplication" minSdk = 24 targetSdk = 33 } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies.apply { add("implementation", "androidx.appcompat:appcompat:1.6.1") // ... } } } }
71. Migrating to convention plugins internal class SampleAndroidApplicationPlugin : Plugin<Project> { override fun apply(project: Project) { with(project) { plugins.apply("com.android.library") plugins.apply("org.jetbrains.kotlin.android") plugins.apply("kotlin-kapt") extensions.getByType(ApplicationExtension::class.java).apply { compileSdk = 33 defaultConfig { applicationId = "com.example.myapplication" minSdk = 24 targetSdk = 33 } compileOptions { sourceCompatibility = JavaVersion.VERSION_11 targetCompatibility = JavaVersion.VERSION_11 } } tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach { kotlinOptions { jvmTarget = JavaVersion.VERSION_11.toString() } } dependencies.apply { add("implementation", "androidx.appcompat:appcompat:1.6.1") // ... } } } }
72. Migrating to convention plugins // app/build.gradle.kts plugins { id("sample.android.application") } dependencies { /* ... */ }
73. Done
74. Achievements, so far...
75. Achievements, so far... • We went from 1000s of lines to 100s of lines of code
76. Achievements, so far... • We went from 1000s of lines to 100s of lines of code • Spreading over in 100s of projects to 1
77. Achievements, so far... • We went from 1000s of lines to 100s of lines of code • Spreading over in 100s of projects to 1 • We now own many Gradle plugins (locally)
78. There's more... // settings.gradle.kts rootProject.name="sample-gradle-project" includeBuild ("build-logic") include (":app") include (":layer_0:module_0_1") include (":layer_0:module_0_2") include (":layer_0:module_0_3") include (":layer_0:module_0_4") include (":layer_0:module_0_5") include (":layer_0:module_0_6") include (":layer_0:module_0_7") include (":layer_0:module_0_8") include (":layer_0:module_0_9") include (":layer_0:module_0_10") include (":layer_0:module_0_11") // ...
79. There's more... // settings.gradle.kts // ... enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") dependencyResolutionManagement { repositories { google().content { includeGroupByRegex("com\\.google.*") includeGroupByRegex("com\\.android.*") includeGroupByRegex("androidx.*") } mavenCentral() } } buildCache { local { isEnabled = true } }
80. There's logic in settings kts // settings.gradle.kts // ... enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") dependencyResolutionManagement { repositories { google().content { includeGroupByRegex("com\\.google.*") includeGroupByRegex("com\\.android.*") includeGroupByRegex("androidx.*") } mavenCentral() } } buildCache { local { isEnabled = true } }
81. There's logic in settings kts // settings.gradle.kts // ... enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") dependencyResolutionManagement { repositories { google().content { includeGroupByRegex("com\\.google.*") includeGroupByRegex("com\\.android.*") includeGroupByRegex("androidx.*") } mavenCentral() } } buildCache { local { isEnabled = true } }
82. There's logic in settings kts // settings.gradle.kts // ... enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") dependencyResolutionManagement { repositories { google().content { includeGroupByRegex("com\\.google.*") includeGroupByRegex("com\\.android.*") includeGroupByRegex("androidx.*") } mavenCentral() } } buildCache { local { isEnabled = true } }
83. Creating a settings convention plugin $ mkdir build-logic-settings $ touch build-logic-settings/build.gradle.kts plugins { `kotlin-dsl` } gradlePlugin { plugins { create("settings") { id = "sample.$name" implementationClass = "convention.SampleSettingsPlugin" } } } repositories { gradlePluginPortal() }
84. Creating a settings convention plugin // build-logic-settings/src/main/kotlin/convention/SampleSettingsPlugin.kt class SampleSettingsPlugin : Plugin<Settings> { override fun apply(settings: Settings) { with(settings) { enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") pluginManagement { configurePluginManagement() } dependencyResolutionManagement { configureRepositories() } pluginManager.apply(GradleBuildCachePlugin::class.java) } } }
85. Creating a settings convention plugin // build-logic-settings/src/main/kotlin/convention/SampleSettingsPlugin.kt class SampleSettingsPlugin : Plugin<Settings> { override fun apply(settings: Settings) { with(settings) { enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") pluginManagement { configurePluginManagement() } dependencyResolutionManagement { configureRepositories() } pluginManager.apply(GradleBuildCachePlugin::class.java) } } }
86. Creating a settings convention plugin // build-logic-settings/src/main/kotlin/convention/SampleSettingsPlugin.kt class SampleSettingsPlugin : Plugin<Settings> { override fun apply(settings: Settings) { with(settings) { enableFeaturePreview("STABLE_CONFIGURATION_CACHE") enableFeaturePreview("TYPESAFE_PROJECT_ACCESSORS") pluginManagement { configurePluginManagement() } dependencyResolutionManagement { configureRepositories() } pluginManager.apply(GradleBuildCachePlugin::class.java) } } }
87. Creating a settings convention plugin // settings.gradle.kts rootProject.name="sample-gradle-project" pluginManagement { includeBuild("build-logic-settings") } plugins { id("sample.settings") }
88. ✅ Pretty much done
89. Tip #3 Android Grade Plugin 8.0.010 now ships with a settings plugin artifact: plugins { id("com.android.settings") version "<agp-version>" } Then we can tweak a few props via the android11 extension. 11 https://developer.android.com/reference/tools/gradle-api/8.0/com/android/build/api/dsl/SettingsExtension 10 https://developer.android.com/build/releases/past-releases/agp-8-0-0-release-notes
90. Apply directly // settings.gradle.kts rootProject.name="sample-gradle-project" pluginManagement { includeBuild("build-logic-settings") } plugins { id("sample.settings") id("com.android.settings") version "8.7.2" }
91. Apply to settings convention plugin plugins { `kotlin-dsl` } dependencies { implementation("com.android.settings:com.android.settings.gradle.plugin:8.7.2") } gradlePlugin { plugins { create("settings") { id = "sample.$name" implementationClass = "convention.SampleSettingsPlugin" } } } repositories { google() gradlePluginPortal() }
92. Apply to settings convention plugin // build-logic-settings/src/main/kotlin/convention/SampleSettingsPlugin.kt import com.android.build.api.dsl.SettingsExtension import com.android.build.gradle.SettingsPlugin class SampleSettingsPlugin : Plugin<Settings> { override fun apply(settings: Settings) { with(settings) { // ... pluginManager.apply(SettingsPlugin::class.java) extensions.getByType<SettingsExtension>().apply { minSdk = 24 compileSdk = 33 } } } }
93. Recap We now have:
94. Recap We now have: 1. Understand how to structure build logic
95. Recap We now have: 1. Understand how to structure build logic 2. Creating and applying convention plugins
96. Not so fast
97. But I use Compose UI... // layer_1/module_1_19/build.gradle.kts plugins { id("sample.android.library") id("org.jetbrains.kotlin.plugin.compose") id("org.jetbrains.compose") } android { buildFeatures { compose = true } } dependencies { debugImplementation("org.jetbrains.compose.ui:ui-tooling-preview:1.7.1") debugImplementation("org.jetbrains.compose.components:components-ui-tooling-preview:1.7.1") implementation("org.jetbrains.compose.ui:ui:1.7.1") implementation("org.jetbrains.compose.runtime:runtime:1.7.1") implementation("org.jetbrains.compose.material3:material3:1.7.1") implementation("org.jetbrains.compose.foundation:foundation:1.7.1") implementation("org.jetbrains.compose.ui:ui-tooling:1.7.1") }
98. But I use Dagger Hilt... // layer_1/module_1_21/build.gradle.kts plugins { id("sample.android.library") id("kotlin-kapt") id("com.google.dagger.hilt.android") } dependencies { implementation("com.google.dagger:hilt-android:2.53.1") kapt("com.google.dagger:hilt-compiler:2.53.1") } kapt { correctErrorTypes = true }
99. What if... // layer_1/module_1_20/build.gradle.kts plugins { id("sample.android.library") } sampleCompany { features { compose() dagger() } }
100. How do I implement it12 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
101. How do I implement it12 1. Create a base plugin 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
102. How do I implement it12 1. Create a base plugin 2. Create a @DslMarker annotation 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
103. How do I implement it12 1. Create a base plugin 2. Create a @DslMarker annotation 3. Create a core DSL class sample { } 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
104. How do I implement it12 1. Create a base plugin 2. Create a @DslMarker annotation 3. Create a core DSL class sample { } 4. Create a nested feature DSL class features { } 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
105. How do I implement it12 1. Create a base plugin 2. Create a @DslMarker annotation 3. Create a core DSL class sample { } 4. Create a nested feature DSL class features { } 5. Create the features 12 https://github.com/anthonymonori/sample-gradle-project/pull/1/files
106. Set up the base plugin // build-logic/src/main/kotlin/com/sample/SampleBasePlugin.kt class SampleBasePlugin : Plugin<Project> { override fun apply(project: Project) { with(project) { val sampleExtension = extensions.create("sample", SampleCompanyExtension::class.java) pluginManager.withPlugin("com.android.application") { configure<BaseAppModuleExtension> { sampleExtension.androidExtension = this } } project.pluginManager.withPlugin("com.android.library") { configure<LibraryExtension> { sampleExtension.androidExtension = this } } sampleExtension.applyTo(this) } } }
107. Set up the base plugin // build-logic/src/main/kotlin/com/sample/SampleBasePlugin.kt class SampleBasePlugin : Plugin<Project> { override fun apply(project: Project) { with(project) { val sampleExtension = extensions.create("sample", SampleCompanyExtension::class.java) pluginManager.withPlugin("com.android.application") { configure<BaseAppModuleExtension> { sampleExtension.androidExtension = this } } project.pluginManager.withPlugin("com.android.library") { configure<LibraryExtension> { sampleExtension.androidExtension = this } } sampleExtension.applyTo(this) } } }
108. Set up the marker and core DSL // build-logic/src/main/kotlin/com/sample/SampleCompanyHandler.kt @DslMarker annotation class SampleCompanyExtensionMarker @SampleCompanyExtensionMarker open class SampleCompanyExtension @Inject internal constructor(objects: ObjectFactory) { private val featuresHandler = objects.newInstance(FeaturesHandler::class.java) fun features(action: Action<FeaturesHandler>) { action.execute(featuresHandler) } internal fun applyTo(project: Project) { project.afterEvaluate { featuresHandler.applyTo(project) } } }
109. Set up the marker and core DSL // build-logic/src/main/kotlin/com/sample/SampleCompanyHandler.kt @DslMarker annotation class SampleCompanyExtensionMarker @SampleCompanyExtensionMarker open class SampleCompanyExtension @Inject internal constructor(objects: ObjectFactory) { private val featuresHandler = objects.newInstance(FeaturesHandler::class.java) fun features(action: Action<FeaturesHandler>) { action.execute(featuresHandler) } internal fun applyTo(project: Project) { project.afterEvaluate { featuresHandler.applyTo(project) } } }
110. Set up the marker and core DSL // build-logic/src/main/kotlin/com/sample/SampleCompanyHandler.kt @DslMarker annotation class SampleCompanyExtensionMarker @SampleCompanyExtensionMarker open class SampleCompanyExtension @Inject internal constructor(objects: ObjectFactory) { private val featuresHandler = objects.newInstance(FeaturesHandler::class.java) fun features(action: Action<FeaturesHandler>) { action.execute(featuresHandler) } internal fun applyTo(project: Project) { project.afterEvaluate { featuresHandler.applyTo(project) } } }
111. Set up the feature DSL // build-logic/src/main/kotlin/com/sample/features/FeatureHandler.kt @SampleCompanyExtensionMarker abstract class FeaturesHandler @Inject internal constructor(objects: ObjectFactory) { private val composeHandler = objects.newInstance<ComposeHandler>() private val daggerHandler = objects.newInstance<DaggerHandler>() internal fun applyTo(project: Project) { composeHandler.applyTo(project) daggerHandler.applyTo(project) } fun compose(action: Action<ComposeHandler>? = null) { composeHandler.enable() action?.execute(composeHandler) } fun dagger(action: Action<DaggerHandler>? = null) { daggerHandler.enable() action?.execute(daggerHandler) } }
112. Set up the feature DSL // build-logic/src/main/kotlin/com/sample/features/FeatureHandler.kt @SampleCompanyExtensionMarker abstract class FeaturesHandler @Inject internal constructor(objects: ObjectFactory) { private val composeHandler = objects.newInstance<ComposeHandler>() private val daggerHandler = objects.newInstance<DaggerHandler>() internal fun applyTo(project: Project) { composeHandler.applyTo(project) daggerHandler.applyTo(project) } fun compose(action: Action<ComposeHandler>? = null) { composeHandler.enable() action?.execute(composeHandler) } fun dagger(action: Action<DaggerHandler>? = null) { daggerHandler.enable() action?.execute(daggerHandler) } }
113. Compose UI feature // build-logic/src/main/kotlin/com/sample/features/ComposeHandler.kt @SampleCompanyExtensionMarker abstract class ComposeHandler @Inject internal constructor(objects: ObjectFactory) { private val enabled = objects.property<Boolean>().convention(false) internal var androidExtension: CommonExtension<*, *, *, *, *, *>? = null internal fun enable() { enabled.set(true) enabled.disallowChanges() androidExtension.apply { buildFeatures { compose = true } } } internal fun applyTo(project: Project) { if (enabled.get()) { project.plugins.apply("org.jetbrains.kotlin.plugin.compose") project.plugins.apply("org.jetbrains.compose") project.dependencies.apply { add("implementation", "org.jetbrains.compose.ui:ui:$composeVersion") add("implementation", "org.jetbrains.compose.runtime:runtime:$composeVersion") // ... } } } }
114. Compose UI feature // build-logic/src/main/kotlin/com/sample/features/ComposeHandler.kt @SampleCompanyExtensionMarker abstract class ComposeHandler @Inject internal constructor(objects: ObjectFactory) { private val enabled = objects.property<Boolean>().convention(false) internal var androidExtension: CommonExtension<*, *, *, *, *, *>? = null internal fun enable() { enabled.set(true) enabled.disallowChanges() androidExtension.apply { buildFeatures { compose = true } } } internal fun applyTo(project: Project) { if (enabled.get()) { project.plugins.apply("org.jetbrains.kotlin.plugin.compose") project.plugins.apply("org.jetbrains.compose") project.dependencies.apply { add("implementation", "org.jetbrains.compose.ui:ui:$composeVersion") add("implementation", "org.jetbrains.compose.runtime:runtime:$composeVersion") // ... } } } }
115. Providing a custom DSL
116. Providing a custom DSL • Declarative, discoverable
117. Providing a custom DSL • Declarative, discoverable • Hides the complexity away
118. Providing a custom DSL • Declarative, discoverable • Hides the complexity away • Allows for easy migrations
119. Changing Dagger KAPT to KSP // build-logic/src/main/kotlin/com/sample/features/DaggerHandler.kt abstract class DaggerHandler @Inject internal constructor(objects: ObjectFactory) { // ... private fun Project.setupDaggerCompiler() { if (useKsp.get()) { pluginManager.apply("com.google.devtools.ksp") dependencies.apply { add("ksp", daggerHiltCompiler) } } else { pluginManager.apply("kotlin-kapt") dependencies.apply { add("kapt", daggerHiltCompiler) } } } }
120. How about discoverability
122. Acknowledgements
123. Herding Elephants 13 13 https://developer.squareup.com/blog/herding-elephants/
124. NowInAndroid 14 14 https://github.com/android/nowinandroid
125. slackhq/foundry 15 15 https://github.com/slackhq/foundry
126. Find me on the Fediverse androiddev.social/@antal
127. Thank you, question?