Publishing Java packages with Gradle

In this tutorial, you'll learn how to use Gradle to publish Java packages to a registry as part of your continuous integration (CI) workflow.

Neste artigo

Introduction

Este guia mostra como criar um fluxo de trabalho que publica pacotes Java no GitHub Packages e no Maven Central Repository. Com um único fluxo de trabalho, você pode publicar pacotes em um único repositório ou em vários repositórios.

Aviso

Os exemplos usados neste guia referem-se ao serviço OSSRH herdado. Consulte Publicação na documentação do Repositório Central do Maven.

Prerequisites

We recommend that you have a basic understanding of workflow files and configuration options. For more information, see Escrevendo fluxos de trabalho.

For more information about creating a CI workflow for your Java project with Gradle, see Building and testing Java with Gradle.

You may also find it helpful to have a basic understanding of the following:

About package configuration

The groupId and artifactId fields in the MavenPublication section of the build.gradle file create a unique identifier for your package that registries use to link your package to a registry. This is similar to the groupId and artifactId fields of the Maven pom.xml file. For more information, see the Maven Publish Plugin in the Gradle documentation.

The build.gradle file also contains configuration for the distribution management repositories that Gradle will publish packages to. Each repository must have a name, a deployment URL, and credentials for authentication.

Publishing packages to the Maven Central Repository

Each time you create a new release, you can trigger a workflow to publish your package. The workflow in the example below runs when the release event triggers with type created. The workflow publishes the package to the Maven Central Repository if CI tests pass. For more information on the release event, see Eventos que disparam fluxos de trabalho.

You can define a new Maven repository in the publishing block of your build.gradle file that points to your package repository. For example, if you were deploying to the Maven Central Repository through the OSSRH hosting project, your build.gradle could specify a repository with the name "OSSRH".

Groovy
plugins {
  ...
  id 'maven-publish'
}

publishing {
  ...

  repositories {
    maven {
      name = "OSSRH"
      url = "https://oss.sonatype.org/service/local/staging/deploy/maven2/"
      credentials {
        username = System.getenv("MAVEN_USERNAME")
        password = System.getenv("MAVEN_PASSWORD")
      }
    }
  }
}

With this configuration, you can create a workflow that publishes your package to the Maven Central Repository by running the gradle publish command. In the deploy step, you’ll need to set environment variables for the username and password or token that you use to authenticate to the Maven repository. For more information, see Using secrets in GitHub Actions.

YAML

# Esse fluxo de trabalho usa ações que não são certificadas pelo GitHub.
# São fornecidas por terceiros e regidas por
# termos de serviço, política de privacidade e suporte separados
# online.

# O GitHub recomenda fixar ações em um SHA de commit.
# Para obter uma versão mais recente, você precisará atualizar o SHA.
# Você também pode fazer referência a uma marca ou branch, mas a ação pode ser alterada sem aviso.

name: Publish package to the Maven Central Repository
on:
  release:
    types: [created]
jobs:
  publish:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up Java
        uses: actions/setup-java@v4
        with:
          java-version: '11'
          distribution: 'temurin'

      - name: Setup Gradle
        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0

      - name: Publish package
        run: ./gradlew publish
        env:
          MAVEN_USERNAME: ${{ secrets.OSSRH_USERNAME }}
          MAVEN_PASSWORD: ${{ secrets.OSSRH_TOKEN }}

Este fluxo de trabalho realiza as etapas a seguir:

  1. Verifica uma cópia do repositório do projeto.

  2. Define o Java JDK.

  3. Configura o ambiente Gradle. A ação gradle/actions/setup-gradle trata do estado de cache entre as execuções de fluxos de trabalho e fornece um resumo com detalhes de todas as execuções do Gradle.

  4. Executes the Gradle publish task to publish to the OSSRH Maven repository. The MAVEN_USERNAME environment variable will be set with the contents of your OSSRH_USERNAME secret, and the MAVEN_PASSWORD environment variable will be set with the contents of your OSSRH_TOKEN secret.

    For more information about using secrets in your workflow, see Using secrets in GitHub Actions.

Publishing packages to GitHub Packages

Each time you create a new release, you can trigger a workflow to publish your package. The workflow in the example below runs when the release event triggers with type created. The workflow publishes the package to GitHub Packages if CI tests pass. For more information on the release event, see Eventos que disparam fluxos de trabalho.

You can define a new Maven repository in the publishing block of your build.gradle that points to GitHub Packages. In that repository configuration, you can also take advantage of environment variables set in your CI workflow run. You can use the GITHUB_ACTOR environment variable as a username, and you can set the GITHUB_TOKEN environment variable with your GITHUB_TOKEN secret.

O segredo GITHUB_TOKEN é definido como um token de acesso para o repositório sempre que um trabalho em um fluxo de trabalho é iniciado. Você deve definir as permissões desse token de acesso no arquivo de fluxo de trabalho para permitir acesso de leitura à permissão contents e acesso de gravação à permissão packages. Para saber mais, confira Use GITHUB_TOKEN in workflows.

For example, if your organization is named "octocat" and your repository is named "hello-world", then the GitHub Packages configuration in build.gradle would look similar to the below example.

Groovy
plugins {
  ...
  id 'maven-publish'
}

publishing {
  ...

  repositories {
    maven {
      name = "GitHubPackages"
      url = "https://maven.pkg.github.com/octocat/hello-world"
      credentials {
        username = System.getenv("GITHUB_ACTOR")
        password = System.getenv("GITHUB_TOKEN")
      }
    }
  }
}

With this configuration, you can create a workflow that publishes your package to GitHub Packages by running the gradle publish command.

YAML

# Esse fluxo de trabalho usa ações que não são certificadas pelo GitHub.
# São fornecidas por terceiros e regidas por
# termos de serviço, política de privacidade e suporte separados
# online.

# O GitHub recomenda fixar ações em um SHA de commit.
# Para obter uma versão mais recente, você precisará atualizar o SHA.
# Você também pode fazer referência a uma marca ou branch, mas a ação pode ser alterada sem aviso.

name: Publish package to GitHub Packages
on:
  release:
    types: [created]
jobs:
  publish:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          java-version: '11'
          distribution: 'temurin'
      - name: Setup Gradle
        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0

      - name: Publish package
        run: ./gradlew publish
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Este fluxo de trabalho realiza as etapas a seguir:

  1. Verifica uma cópia do repositório do projeto.

  2. Define o Java JDK.

  3. Configura o ambiente Gradle. A ação gradle/actions/setup-gradle trata do estado de cache entre as execuções de fluxos de trabalho e fornece um resumo com detalhes de todas as execuções do Gradle.

  4. Executes the Gradle publish task to publish to GitHub Packages. The GITHUB_TOKEN environment variable will be set with the content of the GITHUB_TOKEN secret. The permissions key specifies the access that the GITHUB_TOKEN secret will allow.

    For more information about using secrets in your workflow, see Using secrets in GitHub Actions.

Publishing packages to the Maven Central Repository and GitHub Packages

You can publish your packages to both the Maven Central Repository and GitHub Packages by configuring each in your build.gradle file.

Ensure your build.gradle file includes a repository for both your GitHub repository and your Maven Central Repository provider.

For example, if you deploy to the Central Repository through the OSSRH hosting project, you might want to specify it in a distribution management repository with the name set to OSSRH. If you deploy to GitHub Packages, you might want to specify it in a distribution management repository with the name set to GitHubPackages.

If your organization is named "octocat" and your repository is named "hello-world", then the configuration in build.gradle would look similar to the below example.

Groovy
plugins {
  ...
  id 'maven-publish'
}

publishing {
  ...

  repositories {
    maven {
      name = "OSSRH"
      url = "https://oss.sonatype.org/service/local/staging/deploy/maven2/"
      credentials {
        username = System.getenv("MAVEN_USERNAME")
        password = System.getenv("MAVEN_PASSWORD")
      }
    }
    maven {
      name = "GitHubPackages"
      url = "https://maven.pkg.github.com/octocat/hello-world"
      credentials {
        username = System.getenv("GITHUB_ACTOR")
        password = System.getenv("GITHUB_TOKEN")
      }
    }
  }
}

With this configuration, you can create a workflow that publishes your package to both the Maven Central Repository and GitHub Packages by running the gradle publish command.

YAML

# Esse fluxo de trabalho usa ações que não são certificadas pelo GitHub.
# São fornecidas por terceiros e regidas por
# termos de serviço, política de privacidade e suporte separados
# online.

# O GitHub recomenda fixar ações em um SHA de commit.
# Para obter uma versão mais recente, você precisará atualizar o SHA.
# Você também pode fazer referência a uma marca ou branch, mas a ação pode ser alterada sem aviso.

name: Publish package to the Maven Central Repository and GitHub Packages
on:
  release:
    types: [created]
jobs:
  publish:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4
      - name: Set up Java
        uses: actions/setup-java@v4
        with:
          java-version: '11'
          distribution: 'temurin'
      - name: Setup Gradle
        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0

      - name: Publish package
        run: ./gradlew publish
        env: 
          MAVEN_USERNAME: ${{ secrets.OSSRH_USERNAME }}
          MAVEN_PASSWORD: ${{ secrets.OSSRH_TOKEN }}
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Este fluxo de trabalho realiza as etapas a seguir:

  1. Verifica uma cópia do repositório do projeto.

  2. Define o Java JDK.

  3. Configura o ambiente Gradle. A ação gradle/actions/setup-gradle trata do estado de cache entre as execuções de fluxos de trabalho e fornece um resumo com detalhes de todas as execuções do Gradle.

  4. Executes the Gradle publish task to publish to the OSSRH Maven repository and GitHub Packages. The MAVEN_USERNAME environment variable will be set with the contents of your OSSRH_USERNAME secret, and the MAVEN_PASSWORD environment variable will be set with the contents of your OSSRH_TOKEN secret. The GITHUB_TOKEN environment variable will be set with the content of the GITHUB_TOKEN secret. The permissions key specifies the access that the GITHUB_TOKEN secret will allow.

    For more information about using secrets in your workflow, see Using secrets in GitHub Actions.