Gradle

Gradle (6.6.1)

• requires JDK
• download from [https://gradle.org/releases/]
• can use either Groovy or Kotlin DSL (Domain-Specific Language)

Terminology

• Project: models a software component
• Build script: contains automation instructions for a project
• Task: defines executable automation instructions
  • Ad hoc task: implements one-off, simplistic action code by defining doFirst or doLast, automatically extends DefaultTaslk without having to declare it
  • Typed task: Explicitly declares type (for example, Copy); does not need to define actions as they are already provided by type
• Wrapper:
  • set of files checked into SCM alongside source code
  • standardizes compatible Gradle version for a project
  • automatically downloads the Gradle distribution with defined version

Actions

• doLast, doFirst, …

Files structure for a “Multi-module build”

  root
   + build.gradle
   + moduleA/
   |  + build.gradle
   |   + src/
   + moduleB/
      + build.gradle
     + src/

Commands

• gradle <task name> -> run the task from the build.gradle

• gradle wrapper -> create the wrapper files

  • creates gradlew, gradlew.bat and the gradle directories…

  • gradle/wrapper/gradle-wrapper.properties

  • example:

      distributionBase=GRADLE_USER_HOME
      distributionPath=wrapper/dists
      distributionUrl=https\://services.gradle.org/distributions/gradle-6.6.1-bin.zip
      zipStoreBase=GRADLE_USER_HOME
      zipStorePath=wrapper/dists

  • ./gradlew <task name> -> download the wrapper gradle version and execute the task with it

• gradle projects -> create settings for the project

  • Use settings.gradle do define information, example:

      rootProject.name = "gradle-training"

• gradle <task name> --dry-run -> show the tasks from the build.gradle but does not execute

• gradle tasks --all -> show the full list of available tasks

Example of Typed Task

• example:

    task copyFiles(type: Copy) {
      from "sourceFiles"
      into "target"
      include "**/*md"
      includeEmptyDirs = false
    }
  
    task createZip(type: Zip) {
      from "build/docs"
      archiveFileName = "docs.zip"
      destinationDirectory = file("build/dist")
      dependsOn CopyFiles
    }

Plugins

1. create a reusable or sharable <plugin-name>.gradle file with defined tasks
2. apply the plugin to the local project build.gradle file, example:
   1. plugin with tasks: myPlugin.gradle
   2. in build.gradle:

  apply from: "myPlugin.gradle"

• Notes:

  • available plugins are Core Plugins (from Gradle) and Community Plugins (not from Gradle)
  • to apply Core plugin Base (for example), in build.gradle:

    apply plugin: 'base'