Groovy & Gradle: JVM Automation and Build Engineering · レッスン

タスクとビルドライフサイクル

Gradleタスクを定義・管理し、その依存関係を理解するとともに、ビルドライフサイクルの各段階を把握します。

「タスクとビルドライフサイクル」はCoddyKit上の無料Groovy & Gradle: JVM Automation and Build Engineeringレッスンです。これはレッスン3/4です。下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。これはGroovy & Gradle: JVM Automation and Build Engineering学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Groovy & Gradle: JVM Automation and Build Engineeringコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

What are Gradle Tasks?

Welcome! In this lesson, we'll dive into Gradle Tasks, the fundamental units of work in any Gradle build.

A task represents a single, atomic piece of work that Gradle performs.
Think of tasks as actions like 'compile code', 'run tests', 'clean build directory', or 'deploy application'.
They are the building blocks that make up your entire build process.

Discovering Built-in Tasks

Gradle comes with many built-in tasks. You can list all available tasks for your project using the command line:

gradle tasks

This command shows a categorized list of tasks, including those provided by plugins and any custom tasks you define. It's a great way to explore what your build can do!

Defining Your First Task

Creating your own custom task is straightforward in your build.gradle file. Let's define a simple task:

The task keyword is used, followed by the task's name. The curly braces {} define the task's actions.

task helloWorld {
    println "Hello from CoddyKit Gradle!"
}

Running Custom Tasks

To execute a custom task, you simply run Gradle from your terminal, specifying the task name:

gradle helloWorld

When you run the example from the previous scene, you'll see "Hello from CoddyKit Gradle!" printed in the console.

Task Actions: doLast & doFirst

Tasks can have multiple actions. You can define these actions using doLast and doFirst blocks.

doLast: Adds an action to be executed at the end of the task.
doFirst: Adds an action to be executed at the beginning of the task.

These are useful for organizing complex task logic.

task myGreet {
    doFirst {
        println "Preparing to greet..."
    }
    doLast {
        println "Hello, CoddyKit!"
    }
}

Chaining Tasks with dependsOn

Often, one task must complete before another can start. Gradle handles this with task dependencies using the dependsOn keyword.

If task 'B' depends on task 'A', then 'A' will always run before 'B'. This ensures operations happen in the correct order.

task prepare {
    doLast {
        println "Preparation complete."
    }
}

task build(dependsOn: prepare) {
    doLast {
        println "Build finished."
    }
}

Understanding the Build Lifecycle

Every time you run a Gradle command, it goes through a distinct build lifecycle, consisting of three main phases:

Initialization: Sets up the build environment.
Configuration: Evaluates build scripts and configures tasks.
Execution: Runs the configured tasks.

Understanding these phases is key to writing effective Gradle builds.

Phase 1: Initialization

The Initialization Phase is where Gradle determines which projects are participating in the build.

It evaluates the settings.gradle file (if present).
This file defines the project hierarchy for multi-project builds.
Gradle creates a Project instance for each project involved.

This phase essentially sets the stage for the build.

Phase 2: Configuration

During the Configuration Phase, all build.gradle scripts for the projects are evaluated.

Tasks are created and configured.
Important: Any code directly in a task block (not inside doLast or doFirst) runs during this phase, regardless of whether the task will actually be executed.

This is where tasks' properties and dependencies are set up.

task configExample {
    println "This message runs during Configuration!"
    doLast {
        println "This message runs during Execution!"
    }
}

Phase 3: Execution

The final phase is the Execution Phase. This is where the actual work happens!

Gradle determines which tasks need to run based on your command and task dependencies.
It then executes the doFirst and doLast actions (and any other actions) of those selected tasks.
Tasks are executed in the correct order, respecting their dependencies.

This is when your code compiles, tests run, and artifacts are built.

Lifecycle Check

Let's test your understanding of Gradle's build lifecycle!

Tasks & Lifecycle Recap

Great job! You've learned the core concepts of Gradle tasks and the build lifecycle:

Tasks are the fundamental units of work.
You can define custom tasks and chain them with dependsOn.
The Gradle build proceeds through three phases: Initialization, Configuration, and Execution.
Code directly in a task block runs during Configuration, while doFirst/doLast actions run during Execution.

Next, we'll explore how Gradle manages external dependencies!

よくある質問

「タスクとビルドライフサイクル」レッスンは無料ですか？

はい。「タスクとビルドライフサイクル」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Groovy & Gradle: JVM Automation and Build Engineeringコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Groovy & Gradle: JVM Automation and Build Engineeringコースには全4レッスンが含まれています。

「タスクとビルドライフサイクル」で何を学びますか？

Gradleタスクを定義・管理し、その依存関係を理解するとともに、ビルドライフサイクルの各段階を把握します。ブラウザで直接実行するハンズオンコードでGroovy & Gradle: JVM Automation and Build Engineeringを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

Groovy & Gradle: JVM Automation and Build Engineeringを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのGroovy & Gradle: JVM Automation and Build Engineeringは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。これはレッスン3/4です。

「タスクとビルドライフサイクル」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このGroovy & Gradle: JVM Automation and Build Engineeringレッスンでコードを書いて実行できますか？

はい。すべてのGroovy & Gradle: JVM Automation and Build Engineeringレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

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