Installing Mainsail using Docker

It’s possible to run Mainsail in Docker with our pre-built images. These images are running NGINX with Mainsail. Our images are hosted on the Github Package Registry. You can find more details here.

The image can be pulled using:

$ docker pull ghcr.io/mainsail-crew/mainsail

Configuration for the Docker image

By default the image will connect to localhost:7125. If Moonraker is not running on that address, you can configure Mainsail to behave differently using a config file. You can mount this file in your container.

First make sure that you have a config.json file configured. This is a json file that can look like this:

{
  "instancesDB": "browser"
}

The instanceDB setting value of browser will allow you to manage your printers in the UI.

Alternatively, if you wish to manually specify a list of printers ahead of time, you can use the instanceDB setting value of json. This setting allows you to specify a list of printers directly in the config.json file.

For example, to pre-populate the printer list with two printers:

{
  "instancesDB": "json",
  "instances": [
    { "hostname": "[first_printer_ip_address]", "port": 7125 },
    { "hostname": "[second_printer_ip_address]", "port": 7125 }
  ]
}

Running with the custom configuration

After creating the config.json file the container is ready to run. Make sure you’re executing the command in the same directory as your config.json. Running the following command will launch Mainsail on http://localhost:8080:

$ docker run \
  --name mainsail \
  -v "$(pwd)/config.json:/usr/share/nginx/html/config.json" \
  -p "8080:80" \
  ghcr.io/mainsail-crew/mainsail 

Specifically for Windows, you can run:

docker run --name mainsail -v "%cd%//config.json:/usr/share/nginx/html/config.json" -p "8080:80" ghcr.io/mainsail-crew/mainsail 

Updating the container

docker run will always run the image that’s locally available. To get the latest image locally available, you’ll just need to pull the image again. After that, the docker run command will use the newest version.