Task

Lets create 'Hello world' type of task.

task helloWorld {
    doLast {
        println "Hello World!"
    }
}

When we run gradle tasks --all, we should be able to see that task among other project tasks.

Other tasks
-----------
helloWorld

We can try to execute the task and see what happens. The task prints out 'Hello world' message in console.

➜  gradle helloWorld

> Task :helloWorld
Hello World!


BUILD SUCCESSFUL in 0s
1 actionable task: 1 executed

Tasks using Ant

Ant is available in all Gradle builds.

task antUsed() {
    ant.echo(message: 'Ant called...')
}

Dynamic tasks

Taks can be created in dynamic way.

3.times {
    task "task$it" {
        doLast {
            println "Dynamic task nr $it"
        }
    }
}

Run gradle tasks --all to get all the available tasks. We should be able to see dynamically created tasks there.

Other tasks
-----------
task0
task1
task2

Task dependencies

Tasks can be dependent on other tasks. There can be no circular dependencies (Gradle needs to be able to create an acyclic dependency graph).

task1.dependsOn task0
task2.dependsOn task1
// task1.dependsOn task2 // circular dependency won't work in Gradle
task runWithAllDeps(dependsOn: task2)

Task abbreviation

Almost all the tasks are executable by its abbreviation. If there is conflict in abbreviation uniqueness, Gradle fails to run the task.

task runWithAllDeps(dependsOn: task2) // (gradle rWAD) to run it by abbreviation

Exclude task from execution

Use -x flag to say what tasks should be excluded from task execution.

gradle rWAD -x task0

Task graph

We can hook into the task execution graph.

gradle.taskGraph.whenReady { graph ->
    println "All tasks in Directed Acyclic Graph:"
    println graph.allTasks
}