debian-mirror-gitlab/doc/user/packages/maven_repository/index.md

---
stage: Package
group: Package
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
---

# GitLab Maven Repository

> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/5811) in [GitLab Premium](https://about.gitlab.com/pricing/) 11.3.
> - [Moved](https://gitlab.com/gitlab-org/gitlab/-/issues/221259) to GitLab Core in 13.3.

With the GitLab [Maven](https://maven.apache.org) Repository, every
project can have its own space to store its Maven artifacts.

![GitLab Maven Repository](img/maven_package_view_v12_6.png)

## Enabling the Maven Repository

NOTE: **Note:**
This option is available only if your GitLab administrator has
[enabled support for the Maven repository](../../../administration/packages/index.md).

After the Packages feature is enabled, the Maven Repository is available for
all new projects by default. To enable it for existing projects, or if you want
to disable it:

1. Navigate to your project's **Settings > General > Visibility, project features, permissions**.
1. Find the Packages feature and enable or disable it.
1. Click on **Save changes** for the changes to take effect.

You should then be able to see the **Packages & Registries** section on the left sidebar.
Next, you must configure your project to authorize with the GitLab Maven
repository.

## Getting Started with Maven

This section covers installing Maven and building a package. This is a
quickstart to help if you're new to building Maven packages. If you're already
using Maven and understand how to build your own packages, move onto the
[next section](#adding-the-gitlab-package-registry-as-a-maven-remote).

Maven repositories work well with Gradle, too. Move onto [getting started with Gradle](#getting-started-with-gradle) if you want to setup a Gradle project.

### Installing Maven

The required minimum versions are:

- Java 11.0.5+
- Maven 3.6+

Follow the instructions at [maven.apache.org](https://maven.apache.org/install.html)
to download and install Maven for your local development environment. Once
installation is complete, verify you can use Maven in your terminal by running:

```shell
mvn --version
```

You should see something similar to the below printed in the output:

```shell
Apache Maven 3.6.1 (d66c9c0b3152b2e69ee9bac180bb8fcc8e6af555; 2019-04-04T20:00:29+01:00)
Maven home: /Users/<your_user>/apache-maven-3.6.1
Java version: 12.0.2, vendor: Oracle Corporation, runtime: /Library/Java/JavaVirtualMachines/jdk-12.0.2.jdk/Contents/Home
Default locale: en_GB, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.2", arch: "x86_64", family: "mac"
```

### Creating a project

Understanding how to create a full Java project is outside the scope of this
guide but you can follow the steps below to create a new project that can be
published to the GitLab Package Registry.

Start by opening your terminal and creating a directory where you would like to
store the project in your environment. From inside the directory, you can run
the following Maven command to initialize a new package:

```shell
mvn archetype:generate -DgroupId=com.mycompany.mydepartment -DartifactId=my-project -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false
```

The arguments are as follows:

- `DgroupId`: A unique string that identifies your package. You should follow
the [Maven naming conventions](https://maven.apache.org/guides/mini/guide-naming-conventions.html).
- `DartifactId`: The name of the JAR, appended to the end of the `DgroupId`.
- `DarchetypeArtifactId`: The archetype used to create the initial structure of
the project.
- `DinteractiveMode`: Create the project using batch mode (optional).

After running the command, you should see the following message, indicating that
your project has been set up successfully:

```shell
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.429 s
[INFO] Finished at: 2020-01-28T11:47:04Z
[INFO] ------------------------------------------------------------------------
```

You should see a new directory where you ran this command matching your
`DartifactId` parameter (in this case it should be `my-project`).

## Getting started with Gradle

This section covers installing Gradle and initializing a Java project. This is a
quickstart to help if you're new to Gradle. If you're already
using Gradle and understand how to build your own packages, move onto the
[next section](#adding-the-gitlab-package-registry-as-a-maven-remote).

### Installing Gradle

Installation is needed only if you want to create a new Gradle project. Follow
instructions at [gradle.org](https://gradle.org/install/) to download and install
Gradle for your local development environment.

Verify you can use Gradle in your terminal by running:

```shell
gradle -version
```

If you want to use an existing Gradle project, installation is not necessary.
Simply execute `gradlew` (on Linux) or `gradlew.bat` (on Windows) in the project
directory instead.

You should see something similar to the below printed in the output:

```plaintext
------------------------------------------------------------
Gradle 6.0.1
------------------------------------------------------------

Build time:   2019-11-18 20:25:01 UTC
Revision:     fad121066a68c4701acd362daf4287a7c309a0f5

Kotlin:       1.3.50
Groovy:       2.5.8
Ant:          Apache Ant(TM) version 1.10.7 compiled on September 1 2019
JVM:          11.0.5 (Oracle Corporation 11.0.5+10)
OS:           Windows 10 10.0 amd64
```

### Creating a project in Gradle

Understanding how to create a full Java project in Gradle is outside the scope of this
guide, but you can follow the steps below to create a new project that can be
published to the GitLab Package Registry.

Start by opening your terminal and creating a directory where you would like to
store the project in your environment. From inside the directory, you can run
the following Maven command to initialize a new package:

```shell
gradle init
```

The output should be

```plaintext
Select type of project to generate:
  1: basic
  2: application
  3: library
  4: Gradle plugin
Enter selection (default: basic) [1..4]
```

Enter `3` to create a new Library project. The output should be:

```plaintext
Select implementation language:
  1: C++
  2: Groovy
  3: Java
  4: Kotlin
  5: Scala
  6: Swift
```

Enter `3` to create a new Java Library project. The output should be:

```plaintext
Select build script DSL:
  1: Groovy
  2: Kotlin
Enter selection (default: Groovy) [1..2]
```

Choose `1` to create a new Java Library project which is described in Groovy DSL. The output should be:

```plaintext
Select test framework:
  1: JUnit 4
  2: TestNG
  3: Spock
  4: JUnit Jupiter
```

Choose `1` to initialize the project with JUnit 4 testing libraries. The output should be:

```plaintext
Project name (default: test):
```

Enter a project name or hit enter to use the directory name as project name.

## Adding the GitLab Package Registry as a Maven remote

The next step is to add the GitLab Package Registry as a Maven remote. If a
project is private or you want to upload Maven artifacts to GitLab,
credentials must be provided for authorization too. Support is available
for [personal access tokens](#authenticating-with-a-personal-access-token),
[CI job tokens](#authenticating-with-a-ci-job-token), and
[deploy tokens](../../project/deploy_tokens/index.md) only. Regular username/password
credentials do not work.

### Authenticating with a personal access token

To authenticate with a [personal access token](../../profile/personal_access_tokens.md),
set the scope to `api` when creating one, and add it to your Maven or Gradle configuration
files.

#### Authenticating with a personal access token in Maven

Add a corresponding section to your
[`settings.xml`](https://maven.apache.org/settings.html) file:

```xml
<settings>
  <servers>
    <server>
      <id>gitlab-maven</id>
      <configuration>
        <httpHeaders>
          <property>
            <name>Private-Token</name>
            <value>REPLACE_WITH_YOUR_PERSONAL_ACCESS_TOKEN</value>
          </property>
        </httpHeaders>
      </configuration>
    </server>
  </servers>
</settings>
```

#### Authenticating with a personal access token in Gradle

Create a file `~/.gradle/gradle.properties` with the following content:

```groovy
gitLabPrivateToken=REPLACE_WITH_YOUR_PERSONAL_ACCESS_TOKEN
```

Add a repositories section to your
[`build.gradle`](https://docs.gradle.org/current/userguide/tutorial_using_tasks.html)
file:

```groovy
repositories {
    maven {
        url "https://<gitlab-url>/api/v4/groups/<group>/-/packages/maven"
        name "GitLab"
        credentials(HttpHeaderCredentials) {
            name = 'Private-Token'
            value = gitLabPrivateToken
        }
        authentication {
            header(HttpHeaderAuthentication)
        }
    }
}
```

You should now be able to upload Maven artifacts to your project.

### Authenticating with a CI job token

If you're using GitLab CI/CD, a CI job token can be used instead
of a personal access token.

#### Authenticating with a CI job token in Maven

To authenticate with a CI job token, add a corresponding section to your
[`settings.xml`](https://maven.apache.org/settings.html) file:

```xml
<settings>
  <servers>
    <server>
      <id>gitlab-maven</id>
      <configuration>
        <httpHeaders>
          <property>
            <name>Job-Token</name>
            <value>${env.CI_JOB_TOKEN}</value>
          </property>
        </httpHeaders>
      </configuration>
    </server>
  </servers>
</settings>
```

You can read more on
[how to create Maven packages using GitLab CI/CD](#creating-maven-packages-with-gitlab-cicd).

#### Authenticating with a CI job token in Gradle

To authenticate with a CI job token, add a repositories section to your
[`build.gradle`](https://docs.gradle.org/current/userguide/tutorial_using_tasks.html)
file:

```groovy
repositories {
    maven {
        url "https://<gitlab-url>/api/v4/groups/<group>/-/packages/maven"
        name "GitLab"
        credentials(HttpHeaderCredentials) {
            name = 'Job-Token'
            value = System.getenv("CI_JOB_TOKEN")
        }
        authentication {
            header(HttpHeaderAuthentication)
        }
    }
}
```

### Authenticating with a deploy token

> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/213566) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.0.

To authenticate with a [deploy token](./../../project/deploy_tokens/index.md),
set the scope to `api` when creating one, and add it to your Maven or Gradle configuration
files.

#### Authenticating with a deploy token in Maven

Add a corresponding section to your
[`settings.xml`](https://maven.apache.org/settings.html) file:

```xml
<settings>
  <servers>
    <server>
      <id>gitlab-maven</id>
      <configuration>
        <httpHeaders>
          <property>
            <name>Deploy-Token</name>
            <value>REPLACE_WITH_YOUR_DEPLOY_TOKEN</value>
          </property>
        </httpHeaders>
      </configuration>
    </server>
  </servers>
</settings>
```

#### Authenticating with a deploy token in Gradle

To authenticate with a deploy token, add a repositories section to your
[`build.gradle`](https://docs.gradle.org/current/userguide/tutorial_using_tasks.html)
file:

```groovy
repositories {
    maven {
        url "https://<gitlab-url>/api/v4/groups/<group>/-/packages/maven"
        name "GitLab"
        credentials(HttpHeaderCredentials) {
            name = 'Deploy-Token'
            value = '<deploy-token>'
        }
        authentication {
            header(HttpHeaderAuthentication)
        }
    }
}
```

## Configuring your project to use the GitLab Maven repository URL

To download and upload packages from GitLab, you need a `repository` and
`distributionManagement` section in your `pom.xml` file. If you're following the
steps from above, then you must add the following information to your
`my-project/pom.xml` file.

Depending on your workflow and the amount of Maven packages you have, there are
3 ways you can configure your project to use the GitLab endpoint for Maven packages:

- **Project level**: Useful when you have few Maven packages which are not under
  the same GitLab group.
- **Group level**: Useful when you have many Maven packages under the same GitLab
  group.
- **Instance level**: Useful when you have many Maven packages under different
  GitLab groups or on their own namespace.

NOTE: **Note:**
In all cases, you need a project specific URL for uploading a package in
the `distributionManagement` section.

### Project level Maven endpoint

The example below shows how the relevant `repository` section of your `pom.xml`
would look like in Maven:

```xml
<repositories>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </repository>
</repositories>
<distributionManagement>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </repository>
  <snapshotRepository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </snapshotRepository>
</distributionManagement>
```

The corresponding section in Gradle would look like this:

```groovy
repositories {
    maven {
        url "https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven"
        name "GitLab"
    }
}
```

The `id` must be the same with what you
[defined in `settings.xml`](#adding-the-gitlab-package-registry-as-a-maven-remote).

Replace `PROJECT_ID` with your project ID which can be found on the home page
of your project.

If you have a self-managed GitLab installation, replace `gitlab.com` with your
domain name.

NOTE: **Note:**
For retrieving artifacts, you can use either the
[URL encoded](../../../api/README.md#namespaced-path-encoding) path of the project
(e.g., `group%2Fproject`) or the project's ID (e.g., `42`). However, only the
project's ID can be used for uploading.

### Group level Maven endpoint

> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/8798) in [GitLab Premium](https://about.gitlab.com/pricing/) 11.7.

If you rely on many packages, it might be inefficient to include the `repository` section
with a unique URL for each package. Instead, you can use the group level endpoint for
all your Maven packages stored within one GitLab group. Only packages you have access to
are available for download.

The group level endpoint works with any package names, which means the you
have the flexibility of naming compared to [instance level endpoint](#instance-level-maven-endpoint).
However, GitLab does not guarantee the uniqueness of the package names within
the group. You can have two projects with the same package name and package
version. As a result, GitLab serves whichever one is more recent.

The example below shows how the relevant `repository` section of your `pom.xml`
would look like. You still need a project specific URL for uploading a package in
the `distributionManagement` section:

```xml
<repositories>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/groups/GROUP_ID/-/packages/maven</url>
  </repository>
</repositories>
<distributionManagement>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </repository>
  <snapshotRepository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </snapshotRepository>
</distributionManagement>
```

For Gradle, the corresponding repositories section would look like:

```groovy
repositories {
    maven {
        url "https://gitlab.com/api/v4/groups/GROUP_ID/-/packages/maven"
        name "GitLab"
    }
}
```

The `id` must be the same with what you
[defined in `settings.xml`](#adding-the-gitlab-package-registry-as-a-maven-remote).

Replace `my-group` with your group name and `PROJECT_ID` with your project ID
which can be found on the home page of your project.

If you have a self-managed GitLab installation, replace `gitlab.com` with your
domain name.

NOTE: **Note:**
For retrieving artifacts, you can use either the
[URL encoded](../../../api/README.md#namespaced-path-encoding) path of the group
(e.g., `group%2Fsubgroup`) or the group's ID (e.g., `12`).

### Instance level Maven endpoint

> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/8274) in [GitLab Premium](https://about.gitlab.com/pricing/) 11.7.

If you rely on many packages, it might be inefficient to include the `repository` section
with a unique URL for each package. Instead, you can use the instance level endpoint for
all maven packages stored in GitLab and the packages you have access to are available
for download.

Note that **only packages that have the same path as the project** are exposed via
the instance level endpoint.

| Project | Package | Instance level endpoint available |
| ------- | ------- | --------------------------------- |
| `foo/bar`           | `foo/bar/1.0-SNAPSHOT`           | Yes |
| `gitlab-org/gitlab` | `foo/bar/1.0-SNAPSHOT`           | No  |
| `gitlab-org/gitlab` | `gitlab-org/gitlab/1.0-SNAPSHOT` | Yes |

The example below shows how the relevant `repository` section of your `pom.xml`
would look like. You still need a project specific URL for uploading a package in
the `distributionManagement` section:

```xml
<repositories>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/packages/maven</url>
  </repository>
</repositories>
<distributionManagement>
  <repository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </repository>
  <snapshotRepository>
    <id>gitlab-maven</id>
    <url>https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven</url>
  </snapshotRepository>
</distributionManagement>
```

The corresponding repositories section in Gradle would look like:

```groovy
repositories {
    maven {
        url "https://gitlab.com/api/v4/packages/maven"
        name "GitLab"
    }
}
```

The `id` must be the same with what you
[defined in `settings.xml`](#adding-the-gitlab-package-registry-as-a-maven-remote).

Replace `PROJECT_ID` with your project ID which can be found on the home page
of your project.

If you have a self-managed GitLab installation, replace `gitlab.com` with your
domain name.

NOTE: **Note:**
For retrieving artifacts, you can use either the
[URL encoded](../../../api/README.md#namespaced-path-encoding) path of the project
(e.g., `group%2Fproject`) or the project's ID (e.g., `42`). However, only the
project's ID can be used for uploading.

## Uploading packages

Once you have set up the [remote and authentication](#adding-the-gitlab-package-registry-as-a-maven-remote)
and [configured your project](#configuring-your-project-to-use-the-gitlab-maven-repository-url),
test to upload a Maven artifact from a project of yours.

### Upload using Maven

```shell
mvn deploy
```

If the deploy is successful, you should see the build success message again:

```shell
...
[INFO] BUILD SUCCESS
...
```

You should also see that the upload was uploaded to the correct registry:

```shell
Uploading to gitlab-maven: https://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven/com/mycompany/mydepartment/my-project/1.0-SNAPSHOT/my-project-1.0-20200128.120857-1.jar
```

### Upload using Gradle

Add the Gradle plugin [`maven-publish`](https://docs.gradle.org/current/userguide/publishing_maven.html) to the plugins section:

```groovy
plugins {
    id 'java'
    id 'maven-publish'
}
```

Add a `publishing` section:

```groovy
publishing {
    publications {
        library(MavenPublication) {
            from components.java
        }
    }
    repositories {
        maven {
            url "https://gitlab.com/api/v4/projects/<PROJECT_ID>/packages/maven"
            credentials(HttpHeaderCredentials) {
                name = "Private-Token"
                value = gitLabPrivateToken // the variable resides in ~/.gradle/gradle.properties
            }
            authentication {
                header(HttpHeaderAuthentication)
            }
        }
    }
}
```

Replace `PROJECT_ID` with your project ID which can be found on the home page
of your project.

Run the publish task:

```shell
gradle publish
```

You can then navigate to your project's **Packages & Registries** page and see the uploaded
artifacts or even delete them.

## Installing a package

Installing a package from the GitLab Package Registry requires that you set up
the [remote and authentication](#adding-the-gitlab-package-registry-as-a-maven-remote)
as above. Once this is completed, there are two ways to install a package.

### Install using Maven with `mvn install`

Add the dependency manually to your project `pom.xml` file. To add the example
created above, the XML would look like:

```xml
<dependency>
  <groupId>com.mycompany.mydepartment</groupId>
  <artifactId>my-project</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>
```

Then, inside your project, run the following:

```shell
mvn install
```

Provided everything is set up correctly, you should see the dependency
downloaded from the GitLab Package Registry:

```shell
Downloading from gitlab-maven: http://gitlab.com/api/v4/projects/PROJECT_ID/packages/maven/com/mycompany/mydepartment/my-project/1.0-SNAPSHOT/my-project-1.0-20200128.120857-1.pom
```

### Install using Maven with `mvn dependency:get`

The second way to install packages is to use the Maven commands directly.
Inside your project directory, run:

```shell
mvn dependency:get -Dartifact=com.nickkipling.app:nick-test-app:1.1-SNAPSHOT
```

You should see the same downloading message confirming that the project was
retrieved from the GitLab Package Registry.

TIP: **Tip:**
Both the XML block and Maven command are readily copy and pastable from the
Package details page, allowing for quick and easy installation.

### Install using Gradle

Add a [dependency](https://docs.gradle.org/current/userguide/declaring_dependencies.html) to build.gradle in the dependencies section:

```groovy
dependencies {
    implementation 'com.mycompany.mydepartment:my-project:1.0-SNAPSHOT'
}
```

## Removing a package

In the packages view of your project page, you can delete packages by clicking
the red trash icons or by clicking the **Delete** button on the package details
page.

## Creating Maven packages with GitLab CI/CD

Once you have your repository configured to use the GitLab Maven Repository,
you can configure GitLab CI/CD to build new packages automatically.

### Creating Maven packages with GitLab CI/CD using Maven

The example below shows how to create a new package each time the `master` branch
is updated:

1. Create a `ci_settings.xml` file that serves as Maven's `settings.xml` file.
   Add the server section with the same ID you defined in your `pom.xml` file.
   For example, in our case it's `gitlab-maven`:

   ```xml
   <settings xmlns="http://maven.apache.org/SETTINGS/1.1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.1.0 http://maven.apache.org/xsd/settings-1.1.0.xsd">
     <servers>
       <server>
         <id>gitlab-maven</id>
         <configuration>
           <httpHeaders>
             <property>
               <name>Job-Token</name>
               <value>${env.CI_JOB_TOKEN}</value>
             </property>
           </httpHeaders>
         </configuration>
       </server>
     </servers>
   </settings>
   ```

1. Make sure your `pom.xml` file includes the following:

   ```xml
   <repositories>
     <repository>
       <id>gitlab-maven</id>
       <url>https://gitlab.com/api/v4/projects/${env.CI_PROJECT_ID}/packages/maven</url>
     </repository>
   </repositories>
   <distributionManagement>
     <repository>
       <id>gitlab-maven</id>
       <url>https://gitlab.com/api/v4/projects/${env.CI_PROJECT_ID}/packages/maven</url>
     </repository>
     <snapshotRepository>
       <id>gitlab-maven</id>
       <url>https://gitlab.com/api/v4/projects/${env.CI_PROJECT_ID}/packages/maven</url>
     </snapshotRepository>
   </distributionManagement>
   ```

   TIP: **Tip:**
   You can either let Maven utilize the CI environment variables or hardcode your project's ID.

1. Add a `deploy` job to your `.gitlab-ci.yml` file:

   ```yaml
   deploy:
     image: maven:3.6-jdk-11
     script:
       - 'mvn deploy -s ci_settings.xml'
     only:
       - master
   ```

1. Push those files to your repository.

The next time the `deploy` job runs, it copies `ci_settings.xml` to the
user's home location (in this case the user is `root` since it runs in a
Docker container), and Maven uses the configured CI
[environment variables](../../../ci/variables/README.md#predefined-environment-variables).

### Creating Maven packages with GitLab CI/CD using Gradle

The example below shows how to create a new package each time the `master` branch
is updated:

1. Make sure you use the Job-Token authentication as described in ["Authenticating with a CI job token in Gradle"](#authenticating-with-a-ci-job-token-in-gradle).

1. Add a `deploy` job to your `.gitlab-ci.yml` file:

   ```yaml
   deploy:
     image: gradle:6.5-jdk11
     script:
       - 'gradle publish'
     only:
       - master
   ```

1. Push those files to your repository.

### Version validation

The version string is validated using the following regex.

```ruby
\A(\.?[\w\+-]+\.?)+\z
```

You can play around with the regex and try your version strings on [this regular expression editor](https://rubular.com/r/rrLQqUXjfKEoL6).

## Troubleshooting

### Review network trace logs

If you are having issues with the Maven Repository, you may want to review network trace logs.

For example, try to run `mvn deploy` locally with a PAT token and use these options:

```shell
mvn deploy \
-Dorg.slf4j.simpleLogger.log.org.apache.maven.wagon.providers.http.httpclient=trace \
-Dorg.slf4j.simpleLogger.log.org.apache.maven.wagon.providers.http.httpclient.wire=trace
```

CAUTION: **Caution:**
When you set these options, all network requests are logged and a large amount of output is generated.

### Useful Maven command-line options

There are some [Maven command-line options](https://maven.apache.org/ref/current/maven-embedder/cli.html)
that may be useful when performing tasks with GitLab CI/CD.

- File transfer progress can make the CI logs hard to read.
  Option `-ntp,--no-transfer-progress` was added in
  [3.6.1](https://maven.apache.org/docs/3.6.1/release-notes.html#User_visible_Changes).
  Alternatively, look at `-B,--batch-mode`
  [or lower level logging changes.](https://stackoverflow.com/questions/21638697/disable-maven-download-progress-indication)

- Specify where to find the POM file (`-f,--file`):

   ```yaml
   package:
     script:
       - 'mvn --no-transfer-progress -f helloworld/pom.xml package'
   ```

- Specify where to find the user settings (`-s,--settings`) instead of
  [the default location](https://maven.apache.org/settings.html). There's also a `-gs,--global-settings` option:

   ```yaml
   package:
     script:
       - 'mvn -s settings/ci.xml package'
   ```

### Verifying your Maven settings

If you encounter issues within CI that relate to the `settings.xml` file, it might be useful
to add an additional script task or job to
[verify the effective settings](https://maven.apache.org/plugins/maven-help-plugin/effective-settings-mojo.html).

The help plugin can also provide
[system properties](https://maven.apache.org/plugins/maven-help-plugin/system-mojo.html), including environment variables:

```yaml
mvn-settings:
  script:
    - 'mvn help:effective-settings'

package:
  script:
    - 'mvn help:system'
    - 'mvn package'
```