以前gitのGUI作りたいと思っていろんな試行錯誤して落ち着いたのはClojureScript（re-frame使ったReact）とElectronで作ったUIにRustのgit2-rsで生のgitとのやりとりする方式。まだちょっとややこしいところも残っているが、ほとんどはそれなりにスムーズな開発フローに乗れた。
QUIC and quicker
The past week or so I’ve been working on implementing the QUIC protocol in Clojure. Currently there is no Java implementation to use either (that I know of), and I just found out the other day that netty decided to use the Cloudflare’s Rust library quiche under the hood instead of rolling their own. The protocol is currently a IETF draft at version 32, expected to turn into an RFC soon.
GitOps with Argo
It’s been a year since I wrote about bootstrapping a cluster with Argo and using Argo Rollouts for canary deploys based on Prometheus metrics. Since then many things have changed. I moved from Digital Ocean to Linode (mostly because Linode has a Tokyo region) and from a single-node k3s “cluster” to a 4-node one. But most of how I use Argo CD for GitOps hasn’t changed.
Clojure and Java functional interfaces
Java 8 came out in 2014 and brought along functional interfaces. Functional in general just means that you can treat functions (or methods) as “things” instead of having no proper way to talk about them. In this sense Javascript for example is functional: you can pass around functions all you want. Java’s had Runnable and Callable that are pretty similar in concept.
Then came Java 8 and with it the “mighty arrows.” For some reason Ruby, Javascript and Java all opted to use the same bit of syntax to talk about lambdas (anonymous functions): ->. In Ruby it’s ->(foo) { foo }, in Javascript it’s (foo) -> foo, and surprisingly in Java it’s the same. Run a few rounds with futures and/or streaming stuff and you’ll definitely want to pass such a lambda to forEach for example.
Clojure proxy
Next up in the series complaining about Clojure’s Java interop is proxy. While vararg method calls are inconvenient at worst, there are some (I’d say common) things that simply cannot be achieved with proxy.
Once again this is something I ran into while working with Netty. In one of the HTTP/2 examples, they have one implementation extending AbstractHttp2ConnectionHandlerBuilder<T, B> (have I mentioned I find these extremely long Java class names just hilarious?). The Java implementation is pretty straightforward: implement the abstract method of the class and be done with it.
Clojure vs Java varargs
Variable length argument lists (varargs) have been around since Java 5 (so quite a long while), yet I get the impression that many people either don’t know about this feature or their tools don’t support it. I ran into one of them working with Netty from Clojure and it wasn’t trivial at all how to use them through interop.
Partition of integer into exactly the given number of distinct parts
Ran into this issue in a programming challenge on HackerRank and I was surprised there weren’t any “simple” solutions online. The math related is mostly focused on finding the number of possible partitions of an integer, instead of generating even just one such partition.
A very naive approach might be to enumerate all partitions and then filter them down to those with exactly the wanted number of summands and then filter further to those with distinct parts and pick the first that fulfills the conditions.
But when the subject integer can be 1018 then that simply isn’t realistic. Insert sophisticated simile involving the heat death of the universe.
The algorithms
Honing your skills on CodeWars or HackerRank is definitely a good idea. I’ve myself spent months on the former and some time on the latter, and right there is a display of my issue with them: I lose interest. At first it’s really nice to tackle a bunch of “interesting” problems and feel successful, but as the difficulty of the problems goes up, it soon turns into “how do I get around the shortcomings of the language I use?”
That’s naturally something worth considering, but it just feels so weird when I have to overcome performance tests aimed at C in Ruby (or Clojure). It’s doable (most of the time), but it’s a whole different kind of measure. I recall a problem for which solutions in C were mostly pretty naive loops while something similar in Ruby would fail even the first few load tests.
Counting the milliseconds
I’ve been building a Netty-based web server in Clojure. While I haven’t had the strength to do much with it these past few months because I prioritized the climbing season, now that Hacktoberfest is incoming I’m planning to go pedal to the metal with it (and with my git GUI work-in-progress).
I’m building iny (named after a fox from Fekete Istvan’s Vuk) with the clear goal to replace Aleph. While I’m a huge fan of Aleph and the libraries around it (like Manifold) it’s no longer maintained, which is simply not acceptable when we’re now looking at http/3 coming out sooner than later (support is already in browsers after all).
Going green
There is kind of a status to having your GitHub contributions chart covered in green. For those unfamiliar, it’s a calendar-like chart that shows how active you are on GitHub any given day. It’s assumed that the greener the better. I’m not so sure anymore.
From the start of May to the end of July, I tried filling it up. Do something every day. My conclusion is that this is a typical case of Goodhart’s law. Basically as soon as a certain metric (in this case turning that chart green) becomes a goal in itself, it ceases to be a meaningful metric anymore.
