The build tool needed a runtime the app does not

The deploy fetched the compiler, verified it, compiled every package and ran all
fifty-two tests, and then stopped:

    The program `escript` was not found. Is it installed?

`lustre/dev build` is the obvious way to build a Lustre app and it cannot be the
way this one is built anywhere but here. The app targets JavaScript, but
lustre_dev_tools is an Erlang program — it carries mist and glisten and wisp so
it can run a dev server — so building with it needs an Erlang runtime that the
app itself never uses and the deploy image does not have. Pulling an OTP release
down to run a tool that shells out to esbuild is the wrong trade when esbuild is
a Node package and Node is already installed.

So build.sh does the four things that tool was doing: compile to JavaScript,
bundle with a pinned esbuild, take the shell from assets/index.html, copy the
assets in. It is now the local build as well as the deploy's, so what ships is
what was tested rather than something assembled a second way, and it uses a
compiler that is already installed rather than always fetching one — which is
what made it worth having it work on both platforms.

index.html is checked in rather than generated from a table in gleam.toml. It is
four links and a script tag, and a build step that assembles that from
configuration is indirection over something anyone should be able to open and
read. The table stays for the dev server, which knows no other way to serve a
shell, and each of them says so.

Checked by running the bundle: boot, atlas, a board, a solve and the win screen,
no console errors.

commit

02af01d6be57a4f79795f82536d5b4c98b4872d5

parent

4caad897bcb5b300459eeefae484cd04533ca2f6

author

Dami <dami.etoile@gmail.com>