Run Antora in a Container
The Antora project provides a Docker image so you can run the
antora command inside a container (a process known as containerization).
The benefit of this approach is that you can bypass installing Antora and skip right to running it.
All you need is Docker.
On this page, you’ll learn:
How to run Antora inside a container using the official Docker image for Antora.
How to give the container access to a local directory.
How to extend the Docker image for Antora to create your own image.
Docker is a tool for running container images. You can think of a container image as an application in a box. Inside that box is everything you need to run the application, including the code, the runtime, the settings, and even the operating system itself. Containers not only isolate software from the host environment, they also make it easy to get up and running quickly. And that’s a perfect way to discover and explore Antora!
The Antora project provides an official Docker image named
antora/antora for running Antora inside a container.
This image is published to Docker Hub.
This image is a drop-in replacement for the
Rather than installing the
antora command on your own computer or in a CI environment, you simply run the command by running the container.
In fact, the CI job for the Antora documentation site uses this image to generate the documentation you’re currently reading.
Let’s find out how to run it.
To demonstrate how to use this image, we’ll be using the Antora demo site. Start by cloning the playbook repository for the demo site, then switch to the newly created folder:
~ $ git clone https://gitlab.com/antora/demo/demo-site.git && cd demo-site
Next, execute the
docker run command to invoke the entrypoint command for this image (which is
demo-site $ docker run -u $UID --privileged -v `pwd`:/antora --rm -t antora/antora site.yml
This command spins up a new container from the image, mounts the current directory as the path /antora inside the container, runs the
antora command (as the current user), then stops and removes the container.
It’s exactly like running a locally installed
antora command, only you used container superpowers to do it!
Here’s an explanation of some of the option flags used in this command:
This flag allocates a pseudo-TTY, which is required if you want to see progress bars for git operations. If you don’t need to see these progress bars, you can omit this flag.
This flag is only required if you’re running a Linux distribution that has SELinux enabled by default, such as Fedora. This option allows you to use volume mounts when running SELinux.
This option tells Docker to run the entrypoint command (i.e.,
antora) as the current user. If you use the
--privilegedflag without specifying this option, the generated files are (most likely) written as the root user (and become rather tricky to delete).
If you want Antora to put the cache folder inside the mounted directory, specify a playbook-relative cache directory in the command using the
demo-site $ docker run -u $UID --privileged -v `pwd`:/antora --rm -t antora/antora --cache-dir=./.cache/antora site.yml
Now, all files cached or generated by Antora are neatly self-contained inside the mounted directory (and owned by the current user).
If you want to shell into the container instead of having it run the
antora command, set the
--entrypoint option as follows:
demo-site $ docker run --entrypoint ash --privileged -v `pwd`:/antora --rm -it antora/antora
Now you can run the
antora command from anywhere inside the running container.
This mode is useful to use while editing.
Since the container continues to run, you can quickly execute the
If the base Antora image doesn’t include everything you need for your site, you can extend it.
You can use this image as a base for your own Docker image.
The image comes preconfigured with Yarn so you can install additional extension libraries, such as Asciidoctor Kroki (
asciidoctor-kroki) for adding diagram support to AsciiDoc.
Clone the docker-antora repository and switch to it:
~ $ git clone https://gitlab.com/antora/docker-antora.git && cd docker-antora
Create a custom Dockerfile file named Dockerfile.custom.
Populate the file with the following contents:Dockerfile.custom
FROM antora/antora RUN yarn global add asciidoctor-kroki (1)
1 Adds a custom extension to the base image.
Build the image using the following command:
docker-antora $ docker build -t local/antora:custom -f Dockerfile.custom .
Once the build is finished, you’ll have a new image available on your machine named
To see a list of all your images, run the following command:
$ docker images
To run this image, switch back to your playbook project and run the container as follows:
demo-site $ docker run --privileged -v `pwd`:/antora --rm -t local/antora:custom site.yml
If you want to share this image with others, you’ll need to publish it. Consult the Docker documentation to find out how.