PlantUML & GitLab

Introduced in GitLab 8.16.

When PlantUML integration is enabled and configured in GitLab we are able to create simple diagrams in AsciiDoc and Markdown documents created in snippets, wikis, and repos.

PlantUML Server

Before you can enable PlantUML in GitLab; you need to set up your own PlantUML server that will generate the diagrams. Installing and configuring your own PlantUML server is easy in Debian/Ubuntu distributions using Tomcat.

First you need to create a plantuml.war file from the source code:

sudo apt-get install graphviz openjdk-7-jdk git-core maven
git clone
cd plantuml-server
mvn package

The above sequence of commands will generate a WAR file that can be deployed using Tomcat:

sudo apt-get install tomcat7
sudo cp target/plantuml.war /var/lib/tomcat7/webapps/plantuml.war
sudo chown tomcat7:tomcat7 /var/lib/tomcat7/webapps/plantuml.war
sudo service tomcat7 restart

Once the Tomcat service restarts the PlantUML service will be ready and listening for requests on port 8080:


you can change these defaults by editing the /etc/tomcat7/server.xml file.


You need to enable PlantUML integration from Settings under Admin Area. To do that, login with an Admin account and do following:

  • in GitLab go to Admin Area and then Settings
  • scroll to bottom of the page until PlantUML section
  • check Enable PlantUML checkbox
  • set the PlantUML instance as PlantUML URL

Creating Diagrams

With PlantUML integration enabled and configured, we can start adding diagrams to our AsciiDoc snippets, wikis and repos using delimited blocks:

[plantuml, format="png", id="myDiagram", width="200px"]
Bob->Alice : hello
Alice -> Bob : Go Away

And in Markdown using fenced code blocks:

Bob -> Alice : hello
Alice -> Bob : Go Away

The above blocks will be converted to an HTML img tag with source pointing to the PlantUML instance. If the PlantUML server is correctly configured, this should render a nice diagram instead of the block:

PlantUML Integration

Inside the block you can add any of the supported diagrams by PlantUML such as Sequence, Use Case, Class, Activity, Component, State, and Object diagrams. You do not need to use the PlantUML diagram delimiters @startuml/@enduml as these are replaced by the AsciiDoc plantuml block.

Some parameters can be added to the AsciiDoc block definition:

  • format: Can be either png or svg. Note that svg is not supported by all browsers so use with care. The default is png.
  • id: A CSS id added to the diagram HTML tag.
  • width: Width attribute added to the img tag.
  • height: Height attribute added to the img tag.

Markdown does not support any parameters and will always use PNG format.