Minimal nginx Docker image with antora redirects

antora-playbook.yaml

# snip
urls:
  latest_version_segment_strategy: redirect:from
  latest_version_segment: latest # your choice, doesn't impact the script below
  redirect_facility: nginx
# snip

Dockerfile

FROM nginxinc/nginx-unprivileged:alpine

COPY build/site /usr/share/nginx/html/

# Inject the rewrite rules antora generates into the nginx config:
#  1. Add \ to the end of every line (to make the multi-line sed command in 3. work), and
#     indent all lines (cosmetics).
#  2. Append another ("escaped") empty line (cosmetics).
#  3. Insert what we got before the final closing brace in the default config file.
#     NB: Using % as separator for the replace command because rewrite.conf contains many /
#  4. Clean up
RUN sed -e 's/$/\\/' \
        -e 's/^/    /' \
        < /usr/share/nginx/html/.etc/nginx/rewrite.conf \
        > /tmp/rewrite.conf \
 && echo -e "\\" >> /tmp/rewrite.conf \
 && sed -i -e "s%^}%\n$(cat /tmp/rewrite.conf)}\n%" \
        /etc/nginx/conf.d/default.conf \
 && rm -rf /tmp/rewrite.conf

⚠️ Depending on the deployment (Kubernetes with Route, in my case), further steps are needed (cf. antora/antora#1035). In some cases, it may be enough to extend the above script; add -r and

-e 's% (/[^ ]*)( redirect)?;% \$scheme://\$http_host\1\2;%'

to the sed command in step 1.

⚠️ WIP. Doesn't quite work yet. While the above fixes hostname or port being changed by proxying/forwarding in Kubernetes, the scheme is still mangled in my case. (Not surprising, actually, since HTTPS is terminated in an outer layer.)