Java 애플리케이션 Dockerize 샘플

Author: ahastudio

20240504/java/.dockerignore

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+# Docker
+Dockerfile
+.dockerignore
+
+# Git
+.git
+.gitignore
+.gitattributes
+
+# Gradle
+.gradle
+gradle.properties
+gradlew.bat
+
+# IntelliJ IDEA
+.idea
+
+# Ignore temporary files
+/tmp/

20240504/java/.gitattributes

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+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+

20240504/java/.gitignore

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+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build
+
+# Ignore temporary files
+/tmp/

20240504/java/.sdkmanrc

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+# Enable auto-env through the sdkman_auto_env config
+# Add key=value pairs of SDKs to use below
+java=21.0.3-tem
+gradle=8.7

20240504/java/Dockerfile

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+FROM gradle:8.7-jdk21-alpine AS builder
+
+WORKDIR /u/app
+
+COPY gradle ./gradle
+COPY gradlew .
+COPY settings.gradle.kts .
+COPY build.gradle.kts .
+
+RUN ./gradlew getDeps --no-daemon --info
+
+COPY . .
+
+RUN ./gradlew shadowJar --no-daemon --info
+
+###############################################################################
+
+FROM eclipse-temurin:21-jdk-alpine
+
+WORKDIR /u/app
+
+COPY --from=builder /u/app/build/libs/app-all.jar app.jar
+
+CMD java -jar app.jar

20240504/java/README.md

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+# Java Sample
+
+## SDKMAN! 세팅
+
+- <https://sdkman.io/usage>
+- <https://github.com/ahastudio/til/blob/main/java/sdkman.md>
+
+```bash
+sdk selfupdate
+
+sdk env install
+
+sdk current
+
+sdk env
+```
+
+## 프로젝트 생성
+
+```bash
+gradle init
+```
+
+여기선 `app` 디렉터리를 사용하지 않도록 구조 조정함.
+
+## 의존성 확인
+
+```bash
+./gradlew dependencies
+```
+
+## 의존성 다운로드 테스트
+
+- <https://docs.gradle.org/current/userguide/more_about_tasks.html>
+- <https://docs.gradle.org/current/userguide/working_with_files.html>
+- <https://docs.gradle.org/current/dsl/org.gradle.api.tasks.Copy.html>
+
+`build.gradle.kts` 파일에 `getDeps` 태스크 추가.
+
+```kt
+tasks.register<Copy>("getDeps") {
+    from(configurations.runtimeClasspath)
+    from(configurations.compileClasspath)
+    into("tmp/libs/")
+}
+```
+
+```bash
+./gradlew getDeps
+```
+
+## 빌드
+
+```bash
+./gradlew assemble
+```
+
+## Fat Jar 빌드
+
+- <https://plugins.gradle.org/plugin/io.github.goooler.shadow>
+
+`build.gradle.kts` 파일에 플러그인 추가.
+
+```kt
+plugins {
+    // ...(중략)...
+
+    id("com.github.johnrengelman.plugin-shadow") version "2.0.3"
+}
+```
+
+```bash
+./gradlew shadowJar
+```
+
+## Gradle Docker 이미지 확인
+
+<https://hub.docker.com/_/gradle/>
+
+```bash
+docker run -it --rm gradle:8.7-jdk21-alpine sh
+```
+
+## Docker 이미지 빌드
+
+```bash
+docker build --progress=plain --platform linux/amd64 -t java-sample .
+```
+
+## Docker 컨테이너 실행
+
+```bash
+docker run -it --rm --platform linux/amd64 java-sample
+```

20240504/java/build.gradle.kts

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+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details on building Java & JVM projects, please refer to https://docs.gradle.org/8.7/userguide/building_java_projects.html in the Gradle documentation.
+ * This project uses @Incubating APIs which are subject to change.
+ */
+
+plugins {
+    id("io.github.goooler.shadow") version "8.1.7"
+
+    // Apply the application plugin to add support for building a CLI application in Java.
+    application
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    // This dependency is used by the application.
+    implementation(libs.guava)
+
+    implementation("org.apache.hadoop:hadoop-common:3.3.0")
+}
+
+testing {
+    suites {
+        // Configure the built-in test suite
+        val test by getting(JvmTestSuite::class) {
+            // Use JUnit Jupiter test framework
+            useJUnitJupiter("5.10.1")
+        }
+    }
+}
+
+// Apply a specific Java toolchain to ease working on different environments.
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = "org.example.App"
+}
+
+tasks.register<Copy>("getDeps") {
+    from(configurations.runtimeClasspath)
+    from(configurations.compileClasspath)
+    into("tmp/libs/")
+}

20240504/java/gradle.properties

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+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/build_environment.html#sec:gradle_configuration_properties
+
+org.gradle.parallel=true
+org.gradle.caching=true
+

20240504/java/gradle/libs.versions.toml

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+# This file was generated by the Gradle 'init' task.
+# https://docs.gradle.org/current/userguide/platforms.html#sub::toml-dependencies-format
+
+[versions]
+guava = "32.1.3-jre"
+
+[libraries]
+guava = { module = "com.google.guava:guava", version.ref = "guava" }