My usual go to for building antora sites is with docker. I have a typical makefile that looks like this.

default:
	docker run --rm -v $$PWD:/antora -t antora/antora antora-playbook.yml

However, using docker isn’t supported in cloudflare pages fast builder.

13:21:05.623	Initializing build environment. This may take up to a few minutes to complete
13:21:07.744	Success: Finished initializing build environment
13:21:07.744	Cloning repository...
13:21:09.292	Success: Finished cloning repository files
13:21:09.544	Installing dependencies
13:21:09.556	Python version set to 2.7
13:21:13.527	v12.18.0 is already installed.
13:21:14.918	Now using node v12.18.0 (npm v6.14.4)
13:21:15.264	Started restoring cached build plugins
13:21:15.281	Finished restoring cached build plugins
13:21:15.984	Attempting ruby version 2.7.1, read from environment
13:21:21.912	Using ruby version 2.7.1
13:21:22.295	Using PHP version 5.6
13:21:22.469	5.2 is already installed.
13:21:22.500	Using Swift version 5.2
13:21:22.500	Installing Hugo 0.54.0
13:21:23.170	Hugo Static Site Generator v0.54.0-B1A82C61A/extended linux/amd64 BuildDate: 2019-02-01T10:04:38Z
13:21:23.174	Started restoring cached go cache
13:21:23.196	Finished restoring cached go cache
13:21:23.355	go version go1.14.4 linux/amd64
13:21:23.376	go version go1.14.4 linux/amd64
13:21:23.380	Installing missing commands
13:21:23.380	Verify run directory
13:21:23.381	Executing user command: make
13:21:23.394	docker run --rm -v $PWD:/antora -t antora/antora antora-playbook.yml
13:21:23.400	/bin/sh: 1: docker: not found
13:21:23.400	Makefile:2: recipe for target 'default' failed
13:21:23.401	make: *** [default] Error 127
13:21:23.407	Failed: build command exited with code: 2

So now I need to set it up the manual way instead.

pages:
	npm i -g [email protected]
	antora -v
	antora antora-playbook.yml

Make sure to set a newer node version (NODE_VERSION=16) since it’s too old apparently.

13:29:53.668	npm WARN notsup Unsupported engine for [email protected]: wanted: {"node":">=12.21.0"} (current: {"node":"12.18.0","npm":"6.14.4"})

Complete build log output:

13:39:08.093	Initializing build environment. This may take up to a few minutes to complete
13:39:10.139	Success: Finished initializing build environment
13:39:10.139	Cloning repository...
13:39:11.493	Success: Finished cloning repository files
13:39:11.725	Installing dependencies
13:39:11.737	Python version set to 2.7
13:39:15.612	Downloading and installing node v16.15.0...
13:39:16.098	Downloading https://nodejs.org/dist/v16.15.0/node-v16.15.0-linux-x64.tar.xz...
13:39:16.554	Computing checksum with sha256sum
13:39:16.688	Checksums matched!
13:39:21.169	Now using node v16.15.0 (npm v8.5.5)
13:39:21.737	Started restoring cached build plugins
13:39:21.753	Finished restoring cached build plugins
13:39:22.462	Attempting ruby version 2.7.1, read from environment
13:39:28.312	Using ruby version 2.7.1
13:39:28.670	Using PHP version 5.6
13:39:28.845	5.2 is already installed.
13:39:28.872	Using Swift version 5.2
13:39:28.873	Installing Hugo 0.54.0
13:39:29.542	Hugo Static Site Generator v0.54.0-B1A82C61A/extended linux/amd64 BuildDate: 2019-02-01T10:04:38Z
13:39:29.547	Started restoring cached go cache
13:39:29.568	Finished restoring cached go cache
13:39:29.723	go version go1.14.4 linux/amd64
13:39:29.744	go version go1.14.4 linux/amd64
13:39:29.748	Installing missing commands
13:39:29.749	Verify run directory
13:39:29.749	Executing user command: make pages
13:39:29.762	npm i -g [email protected]
13:39:37.024
13:39:37.024	added 215 packages, and audited 216 packages in 7s
13:39:37.024
13:39:37.024	20 packages are looking for funding
13:39:37.024	  run `npm fund` for details
13:39:37.028
13:39:37.028	8 high severity vulnerabilities
13:39:37.028
13:39:37.028	To address issues that do not require attention, run:
13:39:37.028	  npm audit fix
13:39:37.029
13:39:37.029	Some issues need review, and may require choosing
13:39:37.029	a different dependency.
13:39:37.029
13:39:37.029	Run `npm audit` for details.
13:39:37.043	antora -v
13:39:37.192	@antora/cli: 3.0.1
13:39:37.192	@antora/site-generator: 3.0.1
13:39:37.196	antora antora-playbook.yml
13:39:38.676	Finished
13:39:38.676	Note: No functions dir at /functions found. Skipping.
13:39:38.677	Validating asset output directory
13:39:39.047	Deploying your site to Cloudflare's global network...
13:39:41.663	Success: Your site was deployed!

Good to go 👍🏻