This repository hosts a tool for maintaining a GitHub mirror of the GNU ELPA Emacs Lisp Package Archive. The service is deployed to Railway and runs daily.

GNU ELPA uses an overly complex, unwieldy, and fragile build process. Therefore, running GNU ELPA packages directly from source is not an easy task. In addition to the added complexity when compared to MELPA, running some packages requires a local checkout of the Emacs source repository.

These problems are all neatly avoided if the GNU ELPA build process is run on Railway and the results are mirrored to GitHub, so that the packages can be easily run from source by anyone.

Now, after I set this up, I found that it could be used to solve other problems as well. One is that cloning epkgs, which straight.el uses as an index for the Emacsmirror, takes a while, because it includes a full SQL database. Since straight.el doesn't actually need the contents of that SQL database, only the other information in the repository, GNU ELPA Mirror makes available a mirror of this repository containing only the small files that straight.el actually needs. Note that the actual Emacsmirror packages are not mirrored---that would be somewhat absurd---only the index.

There is a listing of all mirrored GNU ELPA packages. This should correlate roughly with the list of published GNU ELPA packages. Furthermore there is a limited mirror of the Emacsmirror index, which corresponds to information available in epkgs.

The package named <foo> can be found at the URL:

https://github.com/emacs-straight/<foo>

If you use the package manager straight.el, these packages will be automatically used (provided they are not also available from MELPA or Org ELPA) with the following configuration, enabled by default:

(setq straight-recipes-gnu-elpa-use-mirror t)
(setq straight-recipes-emacsmirror-use-mirror t)

This is also documented in the straight.el documentation.

• Create a Railway app named gnu-elpa-mirror.
• Set ACCESS_TOKEN and WEBHOOK_URL as a variables.
• Connect to GitHub.
• Dockerfile auto-detected build should take care of the rest.

Run it locally (in a virtualenv, after installing from requirements.txt):

$ ./gnu_elpa_mirror.py