KotlinでGradleタスクをカスタマイズする方法：効率的なビルドの実現ガイド

tasks.register("hello") {
    doLast {
        println("Hello, Gradle!")
    }
}

./gradlew hello

tasks.register("sayHello") {
    doLast {
        println("Hello, Kotlin Gradle!")
    }
}

tasks.register("greet") {
    doFirst {
        println("Starting the greeting task...")
    }
    doLast {
        println("Hello from Gradle!")
    }
}

tasks.register("printMessage") {
    val message = project.findProperty("message") ?: "Default message"
    doLast {
        println("Message: $message")
    }
}

./gradlew printMessage -Pmessage="Hello, Custom Gradle Task!"

tasks.register("cleanOutput") {
    group = "Cleanup"
    description = "Deletes the output directory."
    doLast {
        delete("build/output")
    }
}

tasks.register("compileKotlin") {
    doLast {
        println("Compiling Kotlin sources...")
    }
}

tasks.register("buildJar") {
    dependsOn("compileKotlin")
    doLast {
        println("Building JAR file...")
    }
}

tasks.register("test") {
    doLast {
        println("Running tests...")
    }
}

tasks.register("packageApp") {
    dependsOn("compileKotlin", "test")
    doLast {
        println("Packaging the application...")
    }
}

tasks.register("conditionalTask") {
    if (project.hasProperty("runTests")) {
        dependsOn("test")
    }
    doLast {
        println("Conditional task executed.")
    }
}

./gradlew conditionalTask -PrunTests

tasks.register("clean") {
    doLast {
        println("Cleaning project...")
    }
}

tasks.register("build") {
    mustRunAfter("clean")
    doLast {
        println("Building project...")
    }
}

tasks.register("deploy") {
    finalizedBy("clean")
    doLast {
        println("Deploying project...")
    }
}

tasks.register("greet") {
    val name: String by project
    doLast {
        println("Hello, $name!")
    }
}

./gradlew greet -Pname="Kotlin User"

tasks.register("welcome") {
    val user = project.findProperty("user") ?: "Guest"
    doLast {
        println("Welcome, $user!")
    }
}

./gradlew welcome

tasks.register("processFile") {
    inputs.file("src/input.txt")
    outputs.file("build/output.txt")

    doLast {
        val inputFile = file("src/input.txt")
        val outputFile = file("build/output.txt")
        outputFile.writeText(inputFile.readText().uppercase())
        println("File processed successfully.")
    }
}

import org.gradle.api.tasks.options.Option

abstract class CustomTask : DefaultTask() {
    @Option(option = "message", description = "Custom message to print")
    var message: String = "Default message"

    @TaskAction
    fun run() {
        println(message)
    }
}

tasks.register<CustomTask>("printCustomMessage")

./gradlew printCustomMessage --message="Hello, Gradle!"

tasks.register("buildProject") {
    val environment = project.findProperty("env") ?: "development"
    val version = project.findProperty("version") ?: "1.0"

    doLast {
        println("Building project for $environment environment, version $version")
    }
}

./gradlew buildProject -Penv=production -Pversion=2.1

tasks.register("cleanBuild") {
    group = "cleanup"
    description = "Deletes the build directory."
    doLast {
        delete("build")
        println("Build directory cleaned.")
    }
}

./gradlew cleanBuild

tasks.register<JavaCompile>("compileCustom") {
    source = fileTree("src/main/java")
    destinationDirectory.set(file("build/classes"))
    options.encoding = "UTF-8"
    doLast {
        println("Compilation completed successfully.")
    }
}

tasks.register<Jar>("createJar") {
    archiveFileName.set("custom-app.jar")
    destinationDirectory.set(file("build/libs"))
    from("build/classes/kotlin/main")
    manifest {
        attributes("Main-Class" to "com.example.MainKt")
    }
    doLast {
        println("Custom JAR created: build/libs/custom-app.jar")
    }
}

./gradlew createJar

tasks.register<Test>("runTests") {
    useJUnitPlatform()
    testLogging {
        events("passed", "failed", "skipped")
    }
    doLast {
        println("All tests completed.")
    }
}

tasks.register("runLint") {
    doLast {
        println("Running static code analysis...")
        // 例: Ktlintのコマンドを呼び出す
        exec {
            commandLine("ktlint", "--reporter=plain")
        }
    }
}

tasks.register<Zip>("zipBuild") {
    archiveFileName.set("project-build.zip")
    destinationDirectory.set(file("build/distributions"))
    from("build/libs")
    doLast {
        println("Build output archived as project-build.zip")
    }
}

./gradlew zipBuild

tasks.register("logExample") {
    doLast {
        logger.lifecycle("INFO: タスクが実行されました。")
        logger.warn("WARN: 警告メッセージです。")
        logger.error("ERROR: エラーメッセージです。")
    }
}

./gradlew logExample

  ./gradlew yourTask

  ./gradlew yourTask --info

  ./gradlew yourTask --debug

  ./gradlew yourTask --quiet

./gradlew yourTask --debug

fun logTaskInfo(taskName: String, message: String) {
    logger.lifecycle("Task [$taskName]: $message")
}

tasks.register("customLogTask") {
    doLast {
        logTaskInfo("customLogTask", "カスタムタスクが実行されました。")
    }
}

tasks.register("errorHandlingTask") {
    doLast {
        try {
            throw IllegalArgumentException("サンプルエラー")
        } catch (e: Exception) {
            logger.error("エラーが発生しました: ${e.message}")
        }
    }
}

   ./gradlew yourTask --debug-jvm

tasks.register<Copy>("copyResources") {
    inputs.dir("src/main/resources")
    outputs.dir("build/resources")

    from("src/main/resources")
    into("build/resources")
}

./gradlew build --parallel

org.gradle.parallel=true

org.gradle.workers.max=4

./gradlew build --build-cache

org.gradle.caching=true

org.gradle.daemon=true

./gradlew build -x test

./gradlew build --scan

val outputDir by lazy { file("build/output") }

tasks.register("generate") {
    doLast {
        outputDir.mkdirs()
        println("Output directory created.")
    }
}

Task 'buildJar' not found in root project 'MyProject'.

  ./gradlew tasks

Cannot call Task.dependsOn(Object...) on a task that has already executed.

  tasks.register("taskA") {
      doLast {
          println("Task A executed")
      }
  }

  tasks.register("taskB") {
      dependsOn("taskA")
      doLast {
          println("Task B executed")
      }
  }

FileNotFoundException: src/main/resources/config.json (No such file or directory)

  tasks.register("createFile") {
      doLast {
          val file = file("src/main/resources/config.json")
          file.parentFile.mkdirs()
          file.writeText("{}")
      }
  }

Type mismatch: inferred type is String but File was expected.

  val outputDir = file("build/output") // 正しい型指定

OutOfMemoryError: Java heap space

  org.gradle.jvmargs=-Xmx2048m

./gradlew cleanBuildCache

Permission denied

  chmod +w build/output