mermaid.ink

Getting Started

git clone https://github.com/jihchi/mermaid.ink.git
cd mermaid.ink
pnpm install
DEBUG=app:* pnpm start

Go to http://localhost:3000

Launch a container

See here for supported tags.

docker run --cap-add=SYS_ADMIN ghcr.io/jihchi/mermaid.ink

Go to http://localhost:3000

If you don't / can't add --cap-add=SYS_ADMIN to the command, please refer to 3 ways to securely use Chrome Headless with this image to find the most suitable solution for your case.

With seccomp

For example, you can use Jessie Frazelle seccomp profile for Chrome:

wget https://raw.githubusercontent.com/jfrazelle/dotfiles/master/etc/docker/seccomp/chrome.json
docker run --security-opt seccomp=$(pwd)/chrome.json ghcr.io/jihchi/mermaid.ink

Environment variables

variable name	default value	description
MAX_WIDTH	10000	Determine the maximum scaled diagram width that can be requested
MAX_HEIGHT	10000	Determine the maximum scaled diagram height that can be requested
FONT_AWESOME_CSS_URL	<unset>	Sets a custom URL for the injected font-awesome CSS in the SVG. The string FA_VERSION will be replaced with the version of font-awesome in use by the application e.g., https://cdnjs.cloudflare.com/ajax/libs/font-awesome/FA_VERSION/css/all.min.css.

Troubleshooting

I'm getting back HTTP 431 Request Header Fields Too Large error

Note that you may encounter DoS if you increase --max-http-header-size!

Thanks @ryepup for the analysis and work-arounds (#12)

• If running locally, add --max-http-header-size to the start script in package.json

  • e.g. "start": "node --max-http-header-size=102400000 src/index.js"

• If running via docker, use NODE_OPTIONS to increase --max-http-header-size

  • e.g. docker run --rm -it -e 'NODE_OPTIONS="--max-http-header-size=102400000"' -p 3000:3000 jihchi/mermaid.ink

Or, If running locally, run NODE_OPTIONS="--max-http-header-size=102400000" npm start to increase --max-http-header-size

Contributors

Many thanks for your help!

The image of contributors is made with contrib.rocks.