This GitHub action renders PlantUML diagrams and pushes the images to your wiki. You can then embed them into your wiki pages.

For rendering, it uses an instance of the PlantUML Java app that runs within your GitHub project instead of the public PlantUML render service. Therefore this action can be safely used in private GitHub projects as it doesn't leak your diagrams to the public.

The following documentation describes the use of this action within an organization, but should work with personal repositories as well.

First make sure that your wiki is initalized. This means that you need to create at least one page in the wiki before this action can push the rendered diagrams to it. Otherwise the action will fail.

Then you need to create an authentication token that gives this action access to your wiki. This is neccessary since ${{ secrets.GITHUB_TOKEN }}, which is automatically available within workflows, doesn't work with the wiki.

Follow this documentation to create the token. Then follow this documentation to add the secret to your organization. Name the secret WIKI_TOKEN.

Now add the following lines to your workflow script:

    - name: Render PlantUML to wiki
      uses: frederikheld/[email protected]
      with:
        WIKI_TOKEN: ${{ secrets.WIKI_TOKEN }}
        INPUT_DIR: 'path/to/input_directory'
        OUTPUT_DIR: 'path/to/output_directory'

You can add this step multiple times to your workflow with different input and output directories, e.g. planning with Gantt charts and architecture with UML diagrams.

NOTE: The generated files be will named after the diagram name specified in @startXYZ diagram name, not after it's original file name! If a file contains multiple diagrams, a separate output file will be generated for each diagram!

To make it easier for you to embed the image, the action will print embedding markup for all available images after rendering is completed.

¹ although the wiki is shown as part of your repository on GitHub, it technically is a separate git repository that you can clone and push changes to. Note that this repo has limited capabilities, e.g. missing support for Git LFS!

This action will recursively look for files that contain @startXYZ in INPUT_DIR of the repo you run this action in and render them into .png files. Those generated files are then copied to OUTPUT_DIR in the wiki of your repo.

You can then embed the images into your wiki pages like this:

[[/path/to/output_directory/my-image.png|alt=alt text]]

In the same way you can set other attributes that can be used with the HTML <img/> tag. Each attribute has to be separated with a pipe symbol. One attribute you might need often is width, as images are embedded in their full size if no size attributes given:

[[/path/to/output_directory/my-image.png|width=300px|alt=alt text]]

• improve speed of docker build by using/creating an image that comes with pre-installed dependencies (right now the preparation takes >1 minute while the rendering only takes seconds)
• split into two separate actions: render to artifact & push artifact to wiki
• allow generation of different file types than PNG
• allow user to set git config user.name and user.email via env variables