bevuta / clojure-nix-locker

Simple and flexible tool to build clojure projects with Nix

clojure-nix-locker

Simple and flexible tool to build clojure projects with Nix.

Usage

The example/ directory has a small clojure program and the nix code required to build it.

To generate/update the lockfile:

nix-shell --run clojure-nix-locker

To build:

nix-build -A uberjar

Why another tool?

There are two existing projects with a similar goal already, clj2nix and clj-nix. Both of these are designed to be used roughly like this:

• At lock-time, call into clojure.tools.deps to resolve all dependencies, then generate a lockfile from this.
• At nix-eval-time, use the information from the lockfile to compute the classpath.
• At build-time, invoke clojure and pass it the precomputed classpath.

By contrast, clojure-nix-locker is designed around letting classpath computation happen later, at build-time. It works roughly like this:

• At lock-time, call arbitrary user-provided commands (like clojure -P) to pre-populate the caches in .m2 and .gitlibs, then crawl those to generate the lockfile.
• At nix-eval-time, use the information from the lockfile to recreate these caches in a way that's "close enough" to the real thing.
• At build-time, invoke clojure as normal. If the prefetching was done correctly, it will resolve its dependencies just fine without hitting the network.

This approach results in a pretty simple implementation and loose coupling to the clojure tooling. As a consequence, things like aliases "just work" without requiring clojure-nix-locker to know about them.

Of course, this has its downsides too:

• If the directory layout of these caches changes, this tool breaks.
• Whatever classpath(s) your clojure tools compute at build-time will only work for the duration of that build.

License

Distributed under the GNU General Public License, Version 3. See LICENSE for more details.