Building and deploying

The build

andromeda:build converts every entry into .andromeda/: parsed, validated, rendered, with components expanded. It is hooked into assets:precompile, so the Dockerfile that ships with Rails 8 — and therefore Kamal, and most other deploy paths — already runs it.

.andromeda/ is a build artifact. The installer adds it to .gitignore and .dockerignore; it is written inside the image at build time.

Tasks

Task	What it does
andromeda:build	Convert everything (runs during assets:precompile)
andromeda:check	Report problems without writing anything — for CI
andromeda:fix	Rewrite camelCase frontmatter keys to snake_case
andromeda:clobber	Remove .andromeda/ (runs during assets:clobber)

In development

There is no watcher to run. A file is converted the first time something asks for it after its content changed, so editing a post and reloading is all there is to it.

In production

The parser never runs while serving a request; pages read the converted result. An entry that was never built raises Andromeda::BuildMissing, whose message names the task to run — a loud failure at boot beats a page that silently converts content on the critical path.

The database

Content needs no database. If your application has one, nothing changes; if it does not, andromeda:build still runs inside a Docker build where no database is reachable, because conversion only ever touches files.

Troubleshooting

ArgumentError: wrong number of arguments (given 2, expected 1) from JSON.parse. Not Andromeda: Rails 8.1 calls JSON.parse with a positional options hash, which version 3 of the json gem removed. Decrypting a session cookie goes through that path, so pages break only once a browser has a session — which looks like “it works in a private window, and breaks when I navigate”. Pin the json gem until Rails ships a fix:

# Gemfile
gem "json", "~> 2.9"