gitlab-org--gitlab-foss/doc/administration/integration/plantuml.md

---
stage: Create
group: Source Code
info: "To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments"
type: reference, howto
---

# PlantUML and GitLab **(FREE)**

When the [PlantUML](https://plantuml.com) integration is enabled and configured in
GitLab, you can create diagrams in snippets, wikis, and repositories. This integration
is enabled on GitLab.com for all SaaS users and does not require any additional configuration.

To set up the integration on a self-managed instance, you must:

1. [Configure your PlantUML server](#configure-your-plantuml-server).
1. [Configure local PlantUML access](#configure-local-plantuml-access).
1. [Configure PlantUML security](#configure-plantuml-security).
1. [Enable the integration](#enable-plantuml-integration).

After completing the integration, PlantUML converts `plantuml`
blocks to an HTML image tag, with the source pointing to the PlantUML instance. The PlantUML
diagram delimiters `@startuml`/`@enduml` aren't required, as these are replaced
by the `plantuml` block:

- **Markdown** files with the extension `.md`:

  ````markdown
  ```plantuml
  Bob -> Alice : hello
  Alice -> Bob : hi
  ```
  ````

  For additional acceptable extensions, review the
  [`languages.yaml`](https://gitlab.com/gitlab-org/gitlab/-/blob/master/vendor/languages.yml#L3174) file.

- **AsciiDoc** files with the extension `.asciidoc`, `.adoc`, or `.asc`:

  ```plaintext
  [plantuml, format="png", id="myDiagram", width="200px"]
  ----
  Bob->Alice : hello
  Alice -> Bob : hi
  ----
  ```

- **reStructuredText**

  ```plaintext
  .. plantuml::
     :caption: Caption with **bold** and *italic*

     Bob -> Alice: hello
     Alice -> Bob: hi
  ```

   Although you can use the `uml::` directive for compatibility with
   [`sphinxcontrib-plantuml`](https://pypi.org/project/sphinxcontrib-plantuml/),
   GitLab supports only the `caption` option.

If the PlantUML server is correctly configured, these examples should render a
diagram instead of the code block:

```plantuml
Bob -> Alice : hello
Alice -> Bob : hi
```

Inside the block you can add any of the diagrams PlantUML supports, such as:

- [Activity](https://plantuml.com/activity-diagram-legacy)
- [Class](https://plantuml.com/class-diagram)
- [Component](https://plantuml.com/component-diagram)
- [Object](https://plantuml.com/object-diagram)
- [Sequence](https://plantuml.com/sequence-diagram)
- [State](https://plantuml.com/state-diagram)
- [Use Case](https://plantuml.com/use-case-diagram)

You can add parameters to block definitions:

- `format`: Can be either `png` (default) or `svg`. Use `svg` with care, as it's
  not supported by all browsers, and isn't supported by Markdown.
- `id`: A CSS ID added to the diagram HTML tag.
- `width`: Width attribute added to the image tag.
- `height`: Height attribute added to the image tag.

Markdown does not support any parameters, and always uses PNG format.

## Configure your PlantUML server

Before you can enable PlantUML in GitLab, set up your own PlantUML
server to generate the diagrams:

- [In Docker](#docker).
- [In Debian/Ubuntu](#debianubuntu).

### Docker

To run a PlantUML container in Docker, run this command:

```shell
docker run -d --name plantuml -p 8080:8080 plantuml/plantuml-server:tomcat
```

The **PlantUML URL** is the hostname of the server running the container.

When running GitLab in Docker, it must have access to the PlantUML container.
To achieve that, use [Docker Compose](https://docs.docker.com/compose/).
In this basic `docker-compose.yml` file, PlantUML is accessible to GitLab at the URL
`http://plantuml:8080/`:

```yaml
version: "3"
services:
  gitlab:
    image: 'gitlab/gitlab-ee:12.2.5-ee.0'
    environment:
      GITLAB_OMNIBUS_CONFIG: |
        nginx['custom_gitlab_server_config'] = "location /-/plantuml/ { \n    proxy_cache off; \n    proxy_pass  http://plantuml:8080/; \n}\n"

  plantuml:
    image: 'plantuml/plantuml-server:tomcat'
    container_name: plantuml
```

### Debian/Ubuntu

You can install and configure a PlantUML server in Debian/Ubuntu distributions
using Tomcat:

1. Run these commands to create a `plantuml.war` file from the source code:

   ```shell
   sudo apt-get install graphviz openjdk-8-jdk git-core maven
   git clone https://github.com/plantuml/plantuml-server.git
   cd plantuml-server
   mvn package
   ```

1. Deploy the `.war` file from the previous step with these commands:

   ```shell
   sudo apt-get install tomcat8
   sudo cp target/plantuml.war /var/lib/tomcat8/webapps/plantuml.war
   sudo chown tomcat8:tomcat8 /var/lib/tomcat8/webapps/plantuml.war
   sudo service tomcat8 restart
   ```

The Tomcat service should restart. After the restart is complete, the
PlantUML service is ready and listening for requests on port 8080:
`http://localhost:8080/plantuml`

To change these defaults, edit the `/etc/tomcat8/server.xml` file.

NOTE:
The default URL is different when using this approach. The Docker-based image
makes the service available at the root URL, with no relative path. Adjust
the configuration below accordingly.

## Configure local PlantUML access

The PlantUML server runs locally on your server, so it can't be accessed
externally by default. Your server must catch external PlantUML
calls to `https://gitlab.example.com/-/plantuml/` and redirect them to the
local PlantUML server. Depending on your setup, the URL is either of the
following:

- `http://plantuml:8080/`
- `http://localhost:8080/plantuml/`

If you're running [GitLab with TLS](https://docs.gitlab.com/omnibus/settings/ssl.html)
you must configure this redirection, because PlantUML uses the insecure HTTP protocol.
Newer browsers such as [Google Chrome 86+](https://www.chromestatus.com/feature/4926989725073408)
don't load insecure HTTP resources on pages served over HTTPS.

To enable this redirection:

1. Add the following line in `/etc/gitlab/gitlab.rb`, depending on your setup method:

   ```ruby
   # Docker deployment
   nginx['custom_gitlab_server_config'] = "location /-/plantuml/ { \n    proxy_cache off; \n    proxy_pass  http://plantuml:8080/; \n}\n"

   # Built from source
   nginx['custom_gitlab_server_config'] = "location /-/plantuml { \n rewrite ^/-/(plantuml.*) /$1 break;\n proxy_cache off; \n proxy_pass http://localhost:8080/plantuml; \n}\n"
   ```

1. To activate the changes, run the following command:

   ```shell
   sudo gitlab-ctl reconfigure
   ```

### Configure PlantUML security

PlantUML has features that allow fetching network resources. If you self-host the
PlantUML server, put network controls in place to isolate it.

```plaintext
@startuml
start
    ' ...
    !include http://localhost/
stop;
@enduml
```

## Enable PlantUML integration

After configuring your local PlantUML server, you're ready to enable the PlantUML integration:

1. Sign in to GitLab as an [Administrator](../../user/permissions.md) user.
1. On the top bar, select **Main menu > Admin**.
1. On the left sidebar, go to **Settings > General** and expand the **PlantUML** section.
1. Select the **Enable PlantUML** checkbox.
1. Set the PlantUML instance as `https://gitlab.example.com/-/plantuml/`,
   and select **Save changes**.

Depending on your PlantUML and GitLab version numbers, you may also need to take
these steps:

- For PlantUML servers running v1.2020.9 and above, such as [plantuml.com](https://plantuml.com),
  you must set the `PLANTUML_ENCODING` environment variable to enable the `deflate`
  compression. In Omnibus GitLab, you can set this value in `/etc/gitlab.rb` with
  this command:

  ```ruby
   gitlab_rails['env'] = { 'PLANTUML_ENCODING' => 'deflate' }
   ```

  In GitLab Helm chart, you can set it by adding a variable to the
  [global.extraEnv](https://gitlab.com/gitlab-org/charts/gitlab/blob/master/doc/charts/globals.md#extraenv)
  section, like this:

  ```yaml
  global:
  extraEnv:
    PLANTUML_ENCODING: deflate
  ```

- For GitLab versions 13.1 and later, PlantUML integration now
  [requires a header prefix in the URL](https://github.com/plantuml/plantuml/issues/117#issuecomment-6235450160)
  to distinguish different encoding types.