Gradle Deep Dive

All about Gradle!

Transcript

1. Gradle deep dive
   Bryan Herbst
   Android Engineer @ Target
   

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2. The toolchain and you
   

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3. Your Code
   

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4. Your Code
   (it’s just text)
   

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5. Build tools
   

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6. Gradle
   

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7. IDE
   

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8. Your Code Build tools Gradle IDE
   

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9. Why Gradle?
   

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10. Reproducible builds
    !
    

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11. Dependency Management
    "
    

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12. Extensibility
    #
    

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13. Faster builds
    $
    

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14. Task automation
    %
    

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15. Other options
    Bazel and Buck
    

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16. Gradle intro
    

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17. Projects
    Every build contains 1+ projects
    

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18. Projects
    Every build contains 1+ projects
    compile ':projectB:childC'
    

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19. Tasks
    Every project contains 1+ tasks
    

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20. Build lifecycle
    Initialization Configuration Execution
    

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21. Gradle Wrapper
    It isn’t that special
    

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22. if (gradleIsNotInstalled) {
    installGradle()
    }
    invokeGradle()
    

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23. Why?
    

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24. Why?
    For consistent builds across machines
    

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25. Tasks
    Things you can do
    

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26. Android Tasks
    • androidDependencies - Displays the Android dependencies of the project.
    • signingReport - Displays the signing info for each variant.
    • sourceSets - Prints out all the source sets defined in this project.
    • assemble - Assembles all variants of all applications and secondary packages.
    • assembleAndroidTest - Assembles all the Test applications.
    • assembleDebug - Assembles all Debug builds.
    • assembleRelease - Assembles all Release builds.
    • build - Assembles and tests this project.
    • buildDependents - Assembles and tests this project and all projects that depend on it.
    • buildNeeded - Assembles and tests this project and all projects it depends on.
    • clean - Deletes the build directory.
    • cleanBuildCache - Deletes the build cache directory.
    • compileDebugAndroidTestSources
    • compileDebugSources
    • compileDebugUnitTestSources
    • compileReleaseSources
    • compileReleaseUnitTestSources
    • mockableAndroidJar - Creates a version of android.jar that's suitable for unit tests.
    • init - Initializes a new Gradle build.
    • wrapper - Generates Gradle wrapper files.
    • buildEnvironment - Displays all buildscript dependencies declared in root project 'HelloWorld'.
    • components - Displays the components produced by root project 'HelloWorld'. [incubating]
    • dependencies - Displays all dependencies declared in root project 'HelloWorld'.
    • dependencyInsight - Displays the insight into a specific dependency in root project 'HelloWorld'.
    • dependentComponents - Displays the dependent components of components in root project 'HelloWorld'.
    [incubating]
    • help - Displays a help message.
    • model - Displays the configuration model of root project 'HelloWorld'. [incubating]
    • projects - Displays the sub-projects of root project 'HelloWorld'.
    • properties - Displays the properties of root project 'HelloWorld'.
    • tasks - Displays the tasks runnable from root project 'HelloWorld' (some of the displayed tasks may belong to
    subprojects).
    • installDebug - Installs the Debug build.
    • installDebugAndroidTest - Installs the android (on device) tests for the Debug build.
    • uninstallAll - Uninstall all applications.
    • uninstallDebug - Uninstalls the Debug build.
    • uninstallDebugAndroidTest - Uninstalls the android (on device) tests for the Debug build.
    • uninstallRelease - Uninstalls the Release build.
    • check - Runs all checks.
    • connectedAndroidTest - Installs and runs instrumentation tests for all flavors on connected devices.
    • connectedCheck - Runs all device checks on currently connected devices.
    • connectedDebugAndroidTest - Installs and runs the tests for debug on connected devices.
    • deviceAndroidTest - Installs and runs instrumentation tests using all Device Providers.
    • deviceCheck - Runs all device checks using Device Providers and Test Servers.
    • lint - Runs lint on all variants.
    • lintDebug - Runs lint on the Debug build.
    • lintRelease - Runs lint on the Release build.
    • test - Run unit tests for all variants.
    • testDebugUnitTest - Run unit tests for the debug build.
    • testReleaseUnitTest - Run unit tests for the release build.
    •
    

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27. (Some) Android Tasks
    • assembleDebug – Assembles all Debug builds.
    • assemble – Assembles all variants of all applications and
    secondary packages.
    • clean – Deletes the build directory
    

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28. (Some) Android Tasks
    • assembleDebug – Assembles all Debug builds.
    • assemble – Assembles all variants of all applications and
    secondary packages.
    • clean – Deletes the build directory
    

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29. (Some) Android Tasks
    • assembleDebug – Assembles all Debug builds.
    • assemble – Assembles all variants of all applications and
    secondary packages.
    • clean – Deletes the build directory
    

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30. task hello {
    doLast {
    println 'Hello world!'
    }
    }
    

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31. doFirst() doLast()
    

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32. doFirst()
    Add to the beginning of
    the action list
    doLast()
    

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33. doFirst()
    Add to the beginning of
    the action list
    doLast()
    Add to the end of the
    action list
    

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34. task hello {
    description 'Says hello'
    group 'Useless tasks'
    doLast {
    println 'Hello world!'
    }
    }
    

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35. Hot off the presses (Gradle 4.2)
    task hello {
    description 'Says hello'
    group 'Useless tasks'
    doLast('Print greeting') {
    println 'Hello world!'
    }
    }
    

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36. task taskX(dependsOn: 'taskY') {
    doLast {
    println 'taskX'
    }
    }
    Will run first
    

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37. class GreetingTask: DefaultTask {
    @TaskAction
    fun greet() {
    println("Hello!")
    }
    }
    

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38. Shortcuts
    ./gradlew tDUT = testDebugUnitTest
    

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39. Shortcuts
    ./gradlew tDUT = testDebugUnitTest
    ./gradlew t = test
    

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40. Shortcuts
    ./gradlew tDUT = testDebugUnitTest
    ./gradlew t = test
    test? tasks?
    

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41. Shortcuts
    ./gradlew tDUT = testDebugUnitTest
    ./gradlew t = test
    ./gradlew te = test
    

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42. Task Outcomes
    • EXECUTED- Task was fully executed
    

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43. Task Outcomes
    • EXECUTED- Task was fully executed
    • UP-TO-DATE- Task inputs/outputs did not change
    

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44. Task Outcomes
    • EXECUTED- Task was fully executed
    • UP-TO-DATE- Task inputs/outputs did not change
    • FROM-CACHE- Output pulled from cache
    

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45. Task Outcomes
    • EXECUTED- Task was fully executed
    • UP-TO-DATE- Task inputs/outputs did not change
    • FROM-CACHE- Output pulled from cache
    • SKIPPED- Task was skipped
    

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46. Task Outcomes
    • EXECUTED- Task was fully executed
    • UP-TO-DATE- Task inputs/outputs did not change
    • FROM-CACHE- Output pulled from cache
    • SKIPPED- Task was skipped
    • NO-SOURCE- Task wasn’t needed
    

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47. Task Outcomes
    • EXECUTED - BAD
    • UP-TO-DATE - GOOD
    • FROM-CACHE - OKAY
    • SKIPPED - GOOD
    • NO-SOURCE - GOOD
    

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48. Plugins
    

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49. class GreetingPlugin implements Plugin {
    void apply(Project project) {
    project.task('hello') {
    doLast {
    println "Hello from the GreetingPlugin"
    }
    }
    }
    }
    

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50. class GreetingPlugin implements Plugin {
    void apply(Project project) {
    project.task('hello') {
    doLast {
    println "Hello from the GreetingPlugin"
    }
    }
    }
    }
    

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51. class GreetingPlugin implements Plugin {
    void apply(Project project) {
    project.task('hello') {
    doLast {
    println "Hello from the GreetingPlugin"
    }
    }
    }
    }
    

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52. Anatomy of a build script
    

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53. Anatomy of a Gradle build script
    buildscript { // ... }
    allprojects { // ... }
    apply plugin: 'kotlin'
    android { // ... }
    dependencies { // ... }
    

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54. buildscript {
    // ...
    }
    Configuration for the
    Gradle build script itself
    allprojects { // ... }
    apply plugin: 'kotlin'
    android { // ... }
    dependencies { // ... }
    

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55. buildscript {
    repositories {
    google()
    jcenter()
    }
    dependencies {
    classpath ’com.foo:bar:1.0.0'
    }
    }
    Dependency repos
    for the build script
    allprojects { // ... }
    apply plugin: 'kotlin'
    android { // ... }
    dependencies { // ... }
    Dependencies for
    the build script
    

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56. allprojects {
    // ...
    }
    Configuration for this
    and all child projects
    apply plugin: 'kotlin'
    android { // ... }
    dependencies { // ... }
    buildscript { // ... }
    

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57. allprojects {
    repositories {
    google()
    jcenter()
    }
    }
    Common dependency
    repo definition
    apply plugin: 'kotlin'
    android { // ... }
    dependencies { // ... }
    buildscript { // ... }
    

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58. apply plugin: 'kotlin' Apply plugins
    android { // ... }
    dependencies { // ... }
    buildscript { // ... }
    allprojects { // ... }
    

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59. android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    }
    Plugin configuration
    DSL
    dependencies { // ... }
    buildscript { // ... }
    allprojects { // ... }
    apply plugin: 'kotlin'
    

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60. dependencies {
    compile 'com.foo:bar:2.1.3'
    testCompile 'junit:junit:4.12'
    }
    Project dependencies
    buildscript { // ... }
    allprojects { // ... }
    apply plugin: 'kotlin'
    android { // ... }
    

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61. android {
    compileSdkVersion 26
    }
    android.compileSdkVersion 26
    =
    

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62. Configurations
    Dependency configurations
    

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63. Configurations (Android)
    • debugCompile
    

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64. Configurations (Android)
    • debugCompile
    • releaseCompile
    

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65. Configurations (Android)
    • debugCompile
    • releaseCompile
    • testCompile
    

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66. Configurations (Android)
    • debugCompile
    • releaseCompile
    • testCompile
    • testDebugCompile
    

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67. Configurations (Android)
    • debugCompile
    • releaseCompile
    • testCompile
    • testDebugCompile
    • testDebugFreeBlueArmv7Compile
    

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68. Custom Configurations
    configurations {
    internalCompile
    debugCompile.extendsFrom(internalCompile)
    dogfoodCompile.extendsFrom(internalCompile)
    }
    dependencies {
    internalCompile '...'
    }
    

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69. Custom Configurations
    configurations {
    internalCompile
    debugCompile.extendsFrom(internalCompile)
    dogfoodCompile.extendsFrom(internalCompile)
    }
    dependencies {
    internalCompile '...'
    }
    

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70. Custom Configurations
    configurations {
    internalCompile
    debugCompile.extendsFrom(internalCompile)
    dogfoodCompile.extendsFrom(internalCompile)
    }
    dependencies {
    internalCompile '...'
    }
    

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71. Gradle Kotlin DSL
    

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72. Static typing
    defaultConfig {
    versionCode "abc"
    versionName 123
    multiDexEnabled "10"
    }
    

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73. Static typing
    defaultConfig {
    versionCode "abc"
    versionName 123
    multiDexEnabled "10"
    }
    

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74. Autocompletion + content assist
    

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75. And more!
    (but it is a little rough)
    

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76. Organizing scripts
    

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77. buildscript { // ... }
    ext.isCi = System.getenv().containsKey("IS_CI")
    task foo {
    doLast {
    if (isCi) {
    // ...
    }
    }
    }
    

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78. buildscript { // ... }
    ext.isCi = System.getenv().containsKey("IS_CI")
    task foo {
    doLast {
    if (isCi) {
    // ...
    }
    }
    }
    

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79. ext.supportLibVersion = "26.0.1"
    dependencies {
    compile "[…]:appcompat-v7:$supportLibVersion"
    compile "[…]:design:$supportLibVersion"
    }
    

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80. Organizing scripts- include
    versions.gradle
    ext.buildTools = "26.0.1"
    ext.compileVersion = 26
    build.gradle
    apply from: 'versions.gradle'
    android {
    buildToolsVersion buildTools
    // ...
    }
    

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81. buildSrc
    Re-usable and testable buildscript code
    

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82. {project}/buildSrc/
    src/main/java - Plugins, tasks, etc.
    

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83. {project}/buildSrc/
    src/main/java - Plugins, tasks, etc.
    build.gradle – Dependencies and configuration
    

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84. {project}/buildSrc/
    src/main/java - Plugins, tasks, etc.
    build.gradle – Dependencies and configuration
    src/test/java – Tests!
    

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85. See Also:
    github.com/android/platform_frameworks_support
    

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86. Getting Build Information
    Knowledge is power
    

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87. apply plugin: 'project-report'
    ./gradlew projectReport
    Provides:
    • Task report
    • dependency report
    • property report
    

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88. apply plugin: 'build-dashboard'
    ./gradlew buildDashboard
    Provides:
    • All reports implementing the reporting interface
    

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89. ./gradlew [task] --profile
    Provides:
    • Build profile by step
    

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90. apply plugin: 'com.gradle.build-scan'
    ./gradlew assembleDebug --scan
    Provides:
    • Shareable, centralized build record
    

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91. Build Scans Demo
    

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92. Improving Build Performance
    

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93. def gitSha = 'git rev-parse --short HEAD’
    .execute([], project.rootDir).text.trim()
    

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94. def gitSha = 'git rev-parse --short HEAD’
    .execute([], project.rootDir).text.trim()
    timestamp = new Date().format('yyyyMMddHHmmss')
    

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95. def gitSha = 'git rev-parse --short HEAD’
    .execute([], project.rootDir).text.trim()
    timestamp = new Date().format('yyyyMMddHHmmss')
    &
    

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96. def gitSha = 'git rev-parse --short HEAD’
    .execute([], project.rootDir).text.trim()
    timestamp = new Date().format('yyyyMMddHHmmss')
    versionNameSuffix = new Date().format('yyyyMMddHHmmss')
    

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97. def gitSha = 'git rev-parse --short HEAD’
    .execute([], project.rootDir).text.trim()
    timestamp = new Date().format('yyyyMMddHHmmss')
    versionNameSuffix = new Date().format('yyyyMMddHHmmss')
    '
    

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98. Gradle Daemon
    Enabled by default as of Gradle 3.0
    

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99. Parallel Builds
    

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100. Parallel Builds
     org.gradle.parallel=true
     

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101. Don’t compile if you don’t need to
     

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102. Don’t compile if you don’t need to
     taskX.onlyIf { !project.hasProperty('skipX') }
     

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103. Don’t compile if you don’t need to
     class TaskX extends DefaultTask {
     @Input def inputProperty
     }
     

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104. Don’t compile if you don’t need to
     class TaskX extends DefaultTask {
     @Input def inputProperty
     }
     Task is now incremental!
     

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105. Android Plugin 3.0.0
     & Gradle 4.x
     Parallel & cacheable
     

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106. Configurations
     compile
     

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107. Configurations
     compile
     testCompile
     

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108. Configurations
     compile
     testCompile
     debugCompile
     

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109. Configurations
     compile
     testCompile
     debugCompile
     apk
     

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110. Configurations
     compile
     testCompile
     debugCompile
     apk
     provided
     

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111. Configurations
     compile
     testCompile
     debugCompile
     apk
     provided
     

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112. Configurations
     implementation Available at compile time,
     Only available to consumers at
     runtime
     

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113. Configurations
     implementation
     api
     Available at compile time and
     run time
     

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114. Configurations
     implementation
     api
     compileOnly
     Only available at compile time
     

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115. Configurations
     implementation
     api
     compileOnly
     runtimeOnly
     Only available at runtime
     

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116. Lib B Lib A App
     

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117. Lib B Lib A App
     Old configurations
     Change
     (recompile)
     

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118. Lib B Lib A App
     Old configurations
     Change
     (recompile)
     recompile
     

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119. Lib B Lib A App
     Old configurations
     Change
     (recompile)
     recompile recompile
     

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120. Lib B Lib A App
     New configurations
     Change
     (recompile)
     recompile
     implementation
     

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121. Plugin 2.2.0
     Gradle 2.14.1
     Plugin 3.0
     Gradle 4.0
     Configuration ~2 mins ~2.5 s
     1-line Java change ~2 mins 15 s ~6.4 s
     

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122. Build cache
     

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123. Build cache
     (not Android’s)
     

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124. Has input
     changed?
     

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125. Has input
     changed?
     UP-TO-DATE
     

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126. Has input
     changed?
     UP-TO-DATE
     In cache?
     

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127. Has input
     changed?
     UP-TO-DATE
     In cache?
     Yes
     FROM-CACHE
     

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128. Has input
     changed?
     UP-TO-DATE
     In cache?
     Yes
     FROM-CACHE
     Execute task
     

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129. Build cache
     org.gradle.caching=true
     Or
     ./gradlew [task] --build-cache
     

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130. Resources
     • google.github.io/android-gradle-dsl
     • github.com/android/platform_frameworks_support
     • gradle.org/docs
     

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