Gradle

Gradle is a build automation tool.

Tasks

Gradle achieves its operations through tasks which are defined in the build.gradle file which is extended with plugins. To define custom tasks and run them with ./gradlew someTask:

task someTask {
    println "Some custom task"
}

Build phases

A task has different phases in its execution:

1. Initialization phase

   • Used to configure multi-project builds

2. Configuration phase

   • Executes code in tasks that's not the action e.g. description

3. Execution phase

   • Execute task actions

Variables

You can define local variables within tasks or share it between tasks with def someVar. To share variables outside the script, use ext someGlobalVar.

Dependencies

Tasks can depend on each other and there are a few ways of achieving this:

1. dependsOn - will be run after task T, doesn't handle circular dependencies

2. mustRunAfter - will detect and fail on circular dependencies

3. shouldRunAfter - doesn't handle circular dependencies

4. finalizedBy - inverted dependency

Order of concurrent task execution is random.

Extending tasks

A common use case is to copy certain files and leverage the Gradle plugin Copy:

// You can filter certain files etc. by setting the relevant properties
task copyStuff (type: Copy) {
    into 'dst'
}