How to Generate Sitemap in Rails App Deployed with Kamal?

I assume you use sitemap_generator gem.

Let’s change bin/docker-entrypoint file so whenever you start this container as a Rails server it will generate the sitemap.

#!/bin/bash -e

# If running the rails server then create or migrate existing database
if [ "${1}" == "./bin/rails" ] && [ "${2}" == "server" ]; then
  ./bin/rails db:prepare
  ./bin/rails sitemap:refresh
fi

exec "${@}"

Make sure the public directory, where the sitemap will be generated, is owned by the rails user, so you won’t have any problems with permissions. Add public to the line that is setting this in your Dockerfile:

# Run and own only the runtime files as a non-root user for security
RUN useradd rails --create-home --shell /bin/bash && \
    chown -R rails:rails db log storage tmp public