This is a proof-of-concept which explores how you might start a greenfield project using Clojure 1.9's tools.deps and CLI.
This proof-of-concept uses:
- tools.deps to track dependencies (third-party libraries and Clojure itself) from Git/GitHub, Maven and a local JAR
- Clojure's CLI to run the program, tests, etc. (The CLI will also install dependencies when necessary.)
- GNU make to provide an ergonomic wrapper around the Clojure CLI
To run the example:
- install Clojure and make sure the
cljbinary is available in your terminal session - clone the repository
- navigate to the repository root
- run
make runormake test
I was inspired by David Nolen's excellent talk, Embracing Simpler Tools, at Clojure/NYC on 5/23/2018.
Also, in my opinion, these features haven't (yet) received their fair due and there aren't (yet) very many resources outside of the official guide/reference.
This Simpler Tools approach is certainly much, ahem, simpler than the
alternative tooling options. When I was able to get dependency management
working (via Maven and local jars), it was a seamless, pleasant experience.
However, I stumbled when trying to use Git coordinates and I'm still not sure
if the problem was with my config, the libraries I was trying to pull in or a
bug in tools.deps. Thanks to /u/alexdmiller for explaining that the
issue I was seeing with Git coordinates is because:
git and local deps only support Maven pom.xml and deps.edn, not project.clj. Prob will be fixed eventually.
In his talk, David suggests using existing, tried-and-true tools as the glue for build tooling/CLI wrappers and I agree that this is a viable path forward. David mentioned Bash scripts, I use make in this example and there are an endless amount of workable alternatives. Perhaps the ability to easily leverage existing tools, like Ant, will make Clojure even more enticing to Java programmers looking to transition. I know very well how frustrating it can be to have to learn an entirely new build/tooling ecosystem in order to even get started learning a new programming language.
The micro-library approach to build tooling does call to mind the old NIH criticisms of the Lisp ecosystem, though. For instance, there is a lot of value in being able to add one line to your project.clj file in order to add a plugin that handles builds/deployments/test runs/etc. It prevents application developers from having to write/maintain brittle, buggy scripts which have nothing to do with their problem domain.
It'll be interesting to see what the community does with the power and flexibility provided by tools.deps and the Clojure CLI. I'm already envisioning a curated repository of build libraries, a la Docker Hub or the Chef Supermarket in order to address the issues raised in the previous paragraph.
I'd like to keep iterating on this project and would not be opposed to it becoming a cookbook of sorts. That would likely mean creating a bunch of different examples, each representing a narrow use case, but let's see how it evolves.
I'd also be happy to accept pull requests. So, if you see something you think could be improved, want to add a new example, etc. please submit a PR!
- Deps and CLI Guide
- Deps and CLI Reference
- JUXT application template (Thanks to vemv on HN for drawing my attention to this project)