Dagger Reflect - The circle from runtime to compile time and back again

Back in the day Java dependency injection frameworks were purely runtime based like Spring and Guava. Dagger 1 introduced a compile time component as well as compile time safety and Dagger 2 took the concept even further. Now we're going back to runtime with Dagger Reflect in an effort to improve local developer build speeds. This talk will cover the reasons for building dagger reflect, how it works under the hood, how to use it in your project as well as how it is developed.

Presented at BerlinDroid Aug 28, 2019
https://www.meetup.com/berlindroid/events/ktlzcryzlblc/

Video here: https://www.droidcon.com/media-detail?video=357540042

1. Dagger Reflect Nelson Osacky from runtime to compile time and back again
3. Me • Android for 9 years • Chocolate and Running • Previously at Square in SF on Build Tools • Currently Working at SoundCloud in Berlin • Maintainer of Fladle - Gradle Plugin for Firebase Test Lab https://github.com/runningcode/fladle • Gradle Doctor - https://github.com/runningcode/gradle- doctor
5. Why?
7. What is Dependency Injection?
8. public class Store {a private Item item; public Store()a{ item = new ItemImpl1(); }a }b
9. public class Store {a private Item item; public Store( )a{ itema=bnew ItemImpl1(); }a }b
10. public class Store {a private Item item; public Store( Itembitem )a{ this.item = item; }a }b
11. public class Store {a private Item item; public Store(Itembitem)a{ this.item = item; }a }b
12. Dependency Injection in the Java world
13. Spring
14. Spring <bean id="item1" class="com.soundcloud.ItemImpl1" /> <bean id="store" class="com.soundcloud.Store"> <constructor-arg type="ItemImpl1" index="0" name="item" ref="item1" /> </bean>
15. Java 1.5 added @Annotations
16. Guice
17. Guice public class Store {c private Item item; public Store(Item item) {d this.item = item; }a }b
18. Guice public class Store {c private Item item; @Inject public Store(Item item) {d this.item = item; }a }b
19. Dagger
20. Dagger public class Store {c private Item item; @Inject public Store(Item item) {d this.item = item; }a }b
21. Dagger @Module public class PlayerModule { @Provides public PlayerProvider providePlayerProvider(AppFeatures appFeatures) { return new PlayerProviderImpl(appfeatures); } }
23. Dagger 2
24. @Component(includes = PlayerModule.class) public interface ApplicationComponent { }
25. Super rough comparison (not to scale) 0 25 50 75 100 Guice Dagger 1 Dagger 2 Compile Time Runtime
29. Dagger Reflect
30. A reflection-based implementation of the Dagger dependency injection library for fast local builds.
31. MyApplication DaggerApplicationComponent
32. @Component public interface ApplicationComponent {b }a
33. @Component public interface ApplicationComponent {b }a DaggerApplicationComponent .factory() .create(this)
34. @Component public interface ApplicationComponent {b @Component.Factory interface Builder {b} }a DaggerApplicationComponent .factory() .create(this)
35. @Component public interface ApplicationComponent {b void inject(MyApplication application); @Component.Factory interface Builder {b} }a DaggerApplicationComponent .factory() .create(this)
36. @Component public interface ApplicationComponent {b void inject(MyApplication application); @Component.Factory interface Builder {b} }a DaggerApplicationComponent .factory() .create(this) .inject(this)
37. class MyApplication : Application(), HasAndroidInjector { override fun onCreate() { super.onCreate() DaggerApplicationComponent .factory() .create(this) .inject(this) } }
38. MyApplication DaggerApplicationComponent Generated by Dagger ~10,000 lines
39. public final class DaggerApplicationComponent { private void initialize(final ApplicationModule applicationModuleParam, final FacebookModule facebookModuleParam, final ApiModule apiModuleParam, final AppFeaturesModule appFeaturesModuleParam, final. BaseAnalyticsModule baseAnalyticsModuleParam, final AdAnalyticsModule adAnalyticsModuleParam, final AppBoyModule appBoyModuleParam, final Application applicationParam) { this.userTopTracksFragmentSubcomponentFactoryProvider = new Provider<UserTopTracksModule_BindUserTopTracksFragment.UserTopTracksFragmentSubcomponent.Factory>() { @Override public UserTopTracksModule_BindUserTopTracksFragment.UserTopTracksFragmentSubcomponent.Factory get( ) { return new UserTopTracksFragmentSubcomponentFactory();} }; this.soundRecorderServiceSubcomponentFactoryProvider = new Provider<CreatorsModule_ProvidesSoundRecorder.SoundRecorderServiceSubcomponent.Factory>() { @Override public CreatorsModule_ProvidesSoundRecorder.SoundRecorderServiceSubcomponent.Factory get() { return new SoundRecorderServiceSubcomponentFactory();} }; this.recordFragmentSubcomponentFactoryProvider = new Provider<CreatorsModule_ProvidesRecordFragment.RecordFragmentSubcomponent.Factory>() { @Override public CreatorsModule_ProvidesRecordFragment.RecordFragmentSubcomponent.Factory get() { return new RecordFragmentSubcomponentFactory();} }; this.recordAppWidgetProviderSubcomponentFactoryProvider = new Provider<CreatorsModule_ProvidesRecordAppWidgetProvider.RecordAppWidgetProviderSubcomponent.Factory>() { @Override public CreatorsModule_ProvidesRecordAppWidgetProvider.RecordAppWidgetProviderSubcomponent.Factory get( ) { return new RecordAppWidgetProviderSubcomponentFactory();} }; this.homescreenWidgetBroadcastReceiverSubcomponentFactoryProvider = new Provider<HomescreenWidgetModule_HomescreenWidgetBroadcastReceiver.HomescreenWidgetBroadcastReceiverSubcomponent.Factory>() { @Override public HomescreenWidgetModule_HomescreenWidgetBroadcastReceiver.HomescreenWidgetBroadcastReceiverSubcomponent.Factory get( ) { return new HomescreenWidgetBroadcastReceiverSubcomponentFactory();} }; this.mainActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindMainActivity.MainActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindMainActivity.MainActivitySubcomponent.Factory get() { return new MainActivitySubcomponentFactory();} }; this.launcherActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindLauncherActivity.LauncherActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindLauncherActivity.LauncherActivitySubcomponent.Factory get() { return new LauncherActivitySubcomponentFactory();} }; this.resolveActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindResolveActivity.ResolveActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindResolveActivity.ResolveActivitySubcomponent.Factory get() { return new ResolveActivitySubcomponentFactory();} }; this.changeStorageLocationActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindChangeLocationStorageActivity.ChangeStorageLocationActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindChangeLocationStorageActivity.ChangeStorageLocationActivitySubcomponent.Factory get( ) { return new ChangeStorageLocationActivitySubcomponentFactory();} }; this.fullScreenVideoActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindFullScreenVideoActivity.FullScreenVideoActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindFullScreenVideoActivity.FullScreenVideoActivitySubcomponent.Factory get( ) { return new FullScreenVideoActivitySubcomponentFactory();} }; this.goOnboardingActivitySubcomponentFactoryProvider = new Provider<ActivityBuilder_BindGoOnboardingActivity.GoOnboardingActivitySubcomponent.Factory>() { @Override public ActivityBuilder_BindGoOnboardingActivity.GoOnboardingActivitySubcomponent.Factory get( ) {
40. MyApplication DaggerApplicationComponent Generated by Dagger ~10,000 lines
41. MyApplication DaggerApplicationComponent Generated by DaggeriReflect 20 lines long
42. MyApplication DaggerApplicationComponent Generated by DaggeriReflect 20 lines long DaggerReflect Dagger Reflect Runtime
43. MyApplication DaggerApplicationComponent DaggerReflect DaggerApplicationComponent
44. MyApplication DaggerApplicationComponent DaggerReflect DaggerApplicationComponent
45. MyApplication DaggerApplicationComponent Generated by DaggeriReflect DaggerReflect DaggerApplicationComponent Generated by Dagger
46. public final class DaggerApplicationComponent {a public static ApplicationComponent.Builder factory() {b return DaggerReflect.factory(ApplicationComponent.Builder.class); }c }d
47. public final class DaggerApplicationComponent {a public static ApplicationComponent.Builder factory() {b return DaggerReflect.factory(ApplicationComponent.Builder.class); }c }d Generated by Dagger Reflect
48. DaggerReflect.factory(ApplicationComponent.Builder.class);
49. DaggerReflect.factory(ApplicationComponent.Builder.class);
50. DaggerReflect factory
51. public final class DaggerReflect {a public static <F> F factory(Class<F> factoryClass) {b }c }d
52. public final class DaggerReflect {a public static <F> F factory(Class<F> factoryClass) {b }c }d In Dagger Reflect Library
53. public final class DaggerReflect {a public static <F> F factory(Class<F> factoryClass) {b return ComponentFactoryInvocationHandler.forComponentFactory(factoryClass); }c }d In Dagger Reflect Library
54. ComponentFactoryInvocationHandler.forComponentFactory(factoryClass); In Dagger Reflect Library
55. ComponentFactoryInvocationHandler In Dagger Reflect Library
56. InvocationHandler
57. InvocationHandler java.lang.Reflect
58. public interface InvocationHandler { public Object invoke(Object proxy, Method method, Object[] args) } java.lang.Reflect
59. InvocationHandler handles method invocations on Proxy classes
60. Proxy classes
61. Proxy classes Implement interfaces at runtime when they are created
62. Create a proxy class at runtime implementing our Component Interface
63. MyApplication DaggerApplicationComponent Generated by DaggeriReflect 20 lines long DaggerReflect Dagger Reflect Runtime
64. MyApplication DaggerApplicationComponent DaggerReflect
65. MyApplication DaggerApplicationComponent Factory DaggerApplicationComponent ComponentFactoryInvocationHandler
66. MyApplication DaggerApplicationComponent.Factory DaggerApplicationComponent ComponentFactoryInvocationHandler
67. ComponentFactoryInvocationHandler.forComponentFactory(factoryClass); In Dagger Reflect Library
68. ComponentFactoryInvocationHandler forComponentFactory In Dagger Reflect Library
69. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
70. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
71. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
72. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
73. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
74. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
75. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
76. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
77. static <F> F forComponentFactory(Class<F> factoryClass) {a requireAnnotation(factoryClass, Component.Factory.class); Class<?> componentClass = requireEnclosingClass(factoryClass); return newProxy( factoryClass, new ComponentFactoryInvocationHandler( componentClass, () -> ComponentScopeBuilder.buildComponent(componentClass))); }b In Dagger Reflect Library
78. ComponentScopeBuilder.buildComponent(componentClass)) In Dagger Reflect Library
79. ComponentScopeBuilder buildComponent In Dagger Reflect Library
80. static ComponentScopeBuilder buildComponent(Class<?> componentClass) {a Component component = requireAnnotation(componentClass, Component.class); Set<Annotation> scopeAnnotation = findScopes(componentClass.getAnnotations()); return create(component.modules(), component.dependencies(), scopeAnnotation, null); }b In Dagger Reflect Library
81. static ComponentScopeBuilder buildComponent(Class<?> componentClass) {a Component component = requireAnnotation(componentClass, Component.class); Set<Annotation> scopeAnnotation = findScopes(componentClass.getAnnotations()); return create(component.modules(), component.dependencies(), scopeAnnotation, null); }b In Dagger Reflect Library
82. static ComponentScopeBuilder buildComponent(Class<?> componentClass) {a Component component = requireAnnotation(componentClass, Component.class); Set<Annotation> scopeAnnotation = findScopes(componentClass.getAnnotations()); return create(component.modules(), component.dependencies(), scopeAnnotation, null); }b In Dagger Reflect Library
83. static ComponentScopeBuilder buildComponent(Class<?> componentClass) {a Component component = requireAnnotation(componentClass, Component.class); Set<Annotation> scopeAnnotation = findScopes(componentClass.getAnnotations()); return create(component.modules(), component.dependencies(), scopeAnnotation, null); }b In Dagger Reflect Library
85. Dagger Reflect Development
86. reflect reflect-compiler integration-tests codegen Project Gradle Setup
87. reflect Reflection based implementation of Dagger
88. reflect reflect-compiler integration-tests codegen Project Gradle Setup
89. reflect-compiler Generates the glue to link your code to the reflection based dagger implementation
90. reflect reflect-compiler integration-tests codegen Project Gradle Setup
91. integration-tests All the tests!
92. integration-tests Make sure we do the same thing as Dagger!
93. integration-tests Make sure we do the same thing as Dagger!
94. @Test public void componentProvider() {a ComponentProvider component = backend.create(ComponentProvider.class); assertThat(component.string()).isEqualTo("foo"); }b
95. @Test public void componentProvider() {a ComponentProvider component = backend.create(ComponentProvider.class); assertThat(component.string()).isEqualTo("foo"); }b @Component(modules = ComponentProvider.Module1.class) interface ComponentProvider { String string(); @Module abstract class Module1 { @Provides static String string() { return "foo"; } } }
96. @Test public void componentProvider() {a ComponentProvider component = backend.create(ComponentProvider.class); assertThat(component.string()).isEqualTo("foo"); }b
97. backend.create(ComponentProvider.class);
98. @RunWith(Parameterized.class) public final class IntegrationTest { @Parameters(name = "{0}") public static Object[] parameters() { return Backend.values(); } @Parameter public Backend backend = backend.create(ComponentProvider.class); }
99. Backend.values();
100. Backend values();
101. enum Backend {a REFLECT, CODEGEN }e
102. enum Backend {a abstract <C> C create(Class<C> componentClass); REFLECT, CODEGEN }e
103. enum Backend {a abstract <C> C create(Class<C> componentClass); REFLECT {b @Overridea <F>aFacreate(Class<F>acomponentClass) { returnaDaggerReflect.create(componentClass); }c },d CODEGEN }e
104. enum Backend {a abstract <C> C create(Class<C> componentClass); REFLECT {b @Overridea <F>aFacreate(Class<F>acomponentClass) { returnaDaggerReflect.create(componentClass); }c },d CODEGEN { @Override <F> F create(Class<F> componentClass) { return DaggerCodegen.create(componentClass); } }; }e
105. backend.create(ComponentProvider.class);
106. @RunWith(Parameterized.class) public final class IntegrationTest { @Parameters(name = "{0}") public static Object[] parameters() { return Backend.values(); } @Parameter public Backend backend = backend.create(ComponentProvider.class); }
107. backend.create(ComponentProvider.class);
108. @Test public void componentProvider() { ComponentProvider component = backend.create(ComponentProvider.class); assertThat(component.string()).isEqualTo("foo"); }
109. How to contribute
110. Try it and write tests
111. @Test public void justInTimeGenericNested()a{ ignoreReflectionBackend(); JustInTimeGenericNested component = backend.create(JustInTimeGenericNested.class); assertThat(component.thing()).isNotNull(); }b
112. pu()a{ ignoreReflectionBackend(); Jus asserTNu }
113. private void ignoreReflectionBackend() { assumeTrue("Not yet implemented for reflection backend", backend != Backend.REFLECT); }
114. @Test public void justInTimeGenericNested()a{ ignoreReflectionBackend(); JustInTimeGenericNested component = backend.create(JustInTimeGenericNested.class); assertThat(component.thing()).isNotNull(); }b
115. @Test public void justInTimeGenericNested() { JustInTimeGenericNested component = backend.create(JustInTimeGenericNested.class); assertThat(component.thing()).isNotNull(); }
116. integration-tests Make sure we do the same thing as Dagger!
117. integration-tests Run the Dagger tests on Dagger Reflect upstream
118. test.filter { // dagger-reflect does not produce the exact same behavior as dagger-compiler for @Reusable. excludeTest 'dagger.functional.ReusableTest', null // TODO reflect bug! Need something like ByteBuddy for proxying classes at runtime. excludeTest 'dagger.functional.builder.BuilderBindsInstanceParameterTest', null // TODO reflect bug! Generics don't work well. excludeTest 'dagger.functional.GenericTest', 'complexGenerics' }
119. Usage
120. Make sure to use @Component.Builder or @Component.Factory
121. @Component interface ApplicationComponent {a }d
122. @Component interface ApplicationComponent {a @Component.Factory interface Factory {b }c }d
123. class MyApplication : Application(), HasAndroidInjector { override fun onCreate() { super.onCreate() DaggerApplicationComponent .factory() .create(this) .inject(this) } }
124. Make sure Dagger Annotations have Runtime Retention
125. @Qualifier public @interface EventGatewayBaseUrl {a }b
126. @Qualifier @Retention(RetentionPolicy.RUNTIME) public @interface EventGatewayBaseUrl {a }b
127. @Qualifier @Retention(RetentionPolicy.RUNTIME) public @interface EventGatewayBaseUrl { } Structural Based Search Inspection
128. Swap Dagger for Dagger Reflect
129. implementation deps.dagger.dagger kapt deps.dagger.compiler
130. implementation deps.dagger.dagger kapt deps.dagger.compiler private fun useDaggerReflect() : Boolean { return properties["dagger.reflect"] == "true") }
131. private fun useDaggerReflect() : Boolean { return properties["dagger.reflect"] == "true") }
132. implementation deps.dagger.dagger if ( useDaggerReflect() ) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler } else { kapt deps.dagger.compiler }
133. implementation deps.dagger.dagger if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler } else { kapt deps.dagger.compiler }
134. Swap Dagger for Dagger Reflect
135. Swap Dagger for Dagger Reflect in every module
136. implementationadeps.dagger.dagger if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler }celse {a kapt deps.dagger.compiler }b
137. implementationadeps.dagger.dagger implementationbdeps.dagger.daggerAndroid if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler }celse {a kapt deps.dagger.compiler kapt deps.dagger.daggerAndroidCompiler }b
138. Swap Dagger for Dagger Reflect in every module
139. Swap Dagger for Dagger Reflect in every module and for Dagger Android
140. Swap Dagger for Dagger Reflect in every module and for Dagger Android and for every new module
141. implementationadeps.dagger.dagger implementationbdeps.dagger.daggerAndroid if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler }celse {a kapt deps.dagger.compiler kapt deps.dagger.daggerAndroidCompiler }b
142. implementationadeps.dagger.dagger implementationbdeps.dagger.daggerAndroid lintChecks deps.dagger.daggerReflectLint if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler }celse {a kapt deps.dagger.compiler kapt deps.dagger.daggerAndroidCompiler }b
143. Swap Dagger for Dagger Reflect in every module and for Dagger Android and for every new module and don’t forget the lint check
144. It’s high maintenance
146. apply plugin: 'com.soundcloud.delect'
147. Dagger Reflect Gradle Plugin
148. apply plugin: 'com.soundcloud.delect'
149. buildscript { classpath 'com.soundcloud.delect:delect-plugin:0.1.0-SNAPSHOT' } apply plugin: 'com.soundcloud.delect'
150. echo "dagger.reflect=true" > ~/.gradle/gradle.properties
151. echo "dagger.reflect=true" > ~/.gradle/gradle.properties
152. Delect
153. implementation deps.dagger.dagger if (useDaggerReflect()) { implementation deps.dagger.reflectRuntime kapt deps.dagger.daggerReflectCompiler } else { kapt deps.dagger.compiler }
154. configurations.all config@ {a dependencies.all {b //bIf we depend on the daggerbruntime, also add the daggerbreflect runtime. ifb(group == daggerGroupId && name == "dagger") {c dependencies {d add(this@config.name, "$com.jakewharton.dagger:dagger-reflect:${extension.daggerReflectVersion}") }e }f }g resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler“) ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p substitute(module("$com.google.dagger:dagger-android-processor")) .with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) }q }r }s
155. configurations.all config@ {a dependencies.all {b //bIf we depend on the daggerbruntime, also add the daggerbreflect runtime. ifb(group == daggerGroupId && name == "dagger") {c dependencies {d add(this@config.name, "$com.jakewharton.dagger:dagger-reflect:${extension.daggerReflectVersion}") }e }f }g }s
156. configurations.all config@ {a dependencies.all {b //bIf we depend on the daggerbruntime, also add the daggerbreflect runtime. ifb(group == daggerGroupId && name == "dagger") {c dependencies {d add(this@config.name, "$com.jakewharton.dagger:dagger-reflect:${extension.daggerReflectVersion}") }e }f }g }s
157. configurations.all config@ {a dependencies.all {b //bIf we depend on the daggerbruntime, also add the daggerbreflect runtime. ifb(group == daggerGroupId && name == "dagger") {c dependencies {d add(this@config.name, "$com.jakewharton.dagger:dagger-reflect:${extension.daggerReflectVersion}") }e }f }g resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler") ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p substitute(module("$com.google.dagger:dagger-android-processor")) .with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) }q }r }s
158. configurations.all config@ {a resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler") ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p }q }r }s
159. configurations.all config@ {a resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler") ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p substitute(module("$com.google.dagger:dagger-android-processor")) .with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) }q }r }s
160. configurations.all config@ {a resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler") ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p substitute(module("$com.google.dagger:dagger-android-processor")) .with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) }q }r }s
161. configurations.all config@ {a dependencies.all {b //bIf we depend on the daggerbruntime, also add the daggerbreflect runtime. ifb(group == daggerGroupId && name == "dagger") {c dependencies {d add(this@config.name, "$com.jakewharton.dagger:dagger-reflect:${extension.daggerReflectVersion}") }e }f }g resolutionStrategy {h dependencySubstitution {o // Substitute dagger compiler for dagger reflect compiler. substitute( module("$com.google.dagger:dagger-compiler") ).apply { with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) because("We want to build faster.") }p substitute(module("$com.google.dagger:dagger-android-processor")) .with(module("$com.jakewharton.dagger:dagger-reflect-compiler:${extension.daggerReflectVersion}")) }q }r }s
162. Let’s talk build times
163. Dagger Reflect Build clean with unique java file 1m54s 1m35s Clean build 31s 26s No-op build 8s 7s Make change to DI 1m8s 1m1s Micro benchmark
170. The longer the build the longer the Dagger time
173. The current state of Dagger Reflect
174. • Slower startup time • Lazy reflection (doesn’t scan entire app at startup) • Different behavior than production • Not all Dagger features are supported yet • Poor error messages
175. Future of Dagger Reflect
176. • Match Dagger with Features • Improve Error Messages • Improve Runtime Performance • Kotlin Dagger Reflect
177. Relative build performance J genating J only K generating K only K & J generating K & J Time https://eng.uber.com/measuring-kotlin-build-performance/
178. At SoundCloud
179. At SoundCloud • Long running side project • Small number of devs using it on master since last week! • Currently running Dagger Reflect behind an opt-in gradle property • Using a fork of Dagger Reflect with our supported features
181. Dagger Reflect a0.1.0a
182. Dagger Reflect a0.1.0a 0.1.0 Delect
196. 58.09s -> 44.68s 23% decrease in build times
197. • Thanks to Riccardo for testing Delect and help with open sourcing • Thanks to my team for testing out Dagger Reflect • Thanks to SoundCloud for letting me have the time to work on this • Thanks Jake Wharton for reviewing my code and building and releasing 0.1.0
198. More information • DIY: Build your own dependency injection library - Pierre- Yves Ricau - https://academy.realm.io/posts/android- pierre-yves-ricau-build-own-dependency-injection/ • Dagger Reflect: https://github.com/jakewharton/dagger- reflect • Dagger Reflect Gradle Plugin: https://github.com/ soundcloud/delect • A brief history of dependency injection http://mvpjava.com/ brief-history-dependency-injection/
199. Thanks nelson@osacky.com Let’s talk build speeds and productivity osacky.com