Task Actions in Gradle (Execution Phase)

Overview

Gradle tasks are composed of actions, which are units of work that are executed in a specific order. This note covers the key methods for defining actions in Gradle tasks:

doLast
doFirst

Key Methods for Defining Task Actions

From doLast

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The doLast method adds an action to the end of a task's execution phase.

This action is executed after all other actions defined in the task have completed.

Usage Example:

tasks.register("exampleTask") {
    doLast {
        println("This action runs after the main task actions.")
    }
}

Syntax: <<

Operator '<<' IS do last

Note: the "<<" is a shorthand notation for "doLast"

task B << {
 println 'action'
}

ref

From doFirst

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`doFirst`

The doFirst method adds an action to the beginning of a task's execution phase. This action is executed before all other actions defined in the task.

Usage Example:

tasks.register("exampleTask") {
    doFirst {
        println("This action runs before the main task actions.")
    }
}

Key Points

Execution Order:
- doFirst actions are executed first.
- doLast actions are executed last.

Example in Context

In a task that prepares a file for logging test results, these methods can ensure the file is properly managed before and after the main task actions:

tasks.register("actionsEg") {
    doFirst {
        println("doFirst-3 will be executed THIRD")
    }
    doFirst {
        println("doFirst-2 will be executed SECOND")
    }
    doLast {
        println("doLast will be executed FOURTH")
    }
    doFirst {
        println("doFirst-1 - will be executed FIRST")
    }
}

Glass thought Sandbox Snapshot

Command to reproduce:

gt.sandbox.checkout.commit 3102345 \
&& cd "${GT_SANDBOX_REPO}" \
&& cmd.run.announce "./gradlew actionsEg"

Recorded output of command:


> Task :lib:actionsEg
doFirst-1 - will be executed FIRST
doFirst-2 will be executed SECOND
doFirst-3 will be executed THIRD
doLast will be executed FOURTH

BUILD SUCCESSFUL in 359ms
1 actionable task: 1 executed

Reverse order

Multiple doFirst and doLast blocks are executed in the reverse order they are defined

Just avoid having multiple doFirst or doLast in the same task

Children

Backlinks

Gradle Lifecycle