I’ve never used Haskell. I won’t claim I’m good at Rust. I mostly work with Ruby and Clojure, both dynamic languages where you don’t really need to worry about types. But then of course that’s not true. Even if you put Rails’s magic aside, it’s way too easy to write code that accidentally works (in an absolutely unintended fashion).
I’ve been reading about and considering language design choices (for my new pet project), and one thing I really like (though I rarely actually use in action) is Clojure’s transducers. I couldn’t find it in the talk introducing them, but I vaguely recall someone vaguely recalling that Rich Hickey said Clojure’d have much less laziness if he’d found the idea of transducers sooner.
Then in a completely different thought process (maybe there could be transducers, process transformations for thought processes as well?) about databases. I was considering databases I used so far, things I tried to achieve with them, the difficulties and nice things.
It was a while back that I got a notice from Shibuya lisp that the 100th event is coming up. It’s a (Common) Lisp/Clojure meetup in Tokyo (though since covid, online). I don’t know if it’s a common thing among lispers, but everyone there seems to at least try writing their own lisp (and talk about it) somewhere down the path.
Before I wasn’t that interested. I could do most of what I wanted to do in Clojure without too much pain. Then I tried writing a (performant) wrapper around Netty and it got a bit more painful. Things like nth calls on function argument lists started showing up on my flame charts (testing with 100 million requests) and rough edges around interop cut my hands (hello proxy and abstract classes).
My cluster is now running on k3s 1.20.6 and Argo CD 2.0.0 with its Helm chart at 3.2.2. Actually, upgrading Argo itself wasn’t much of a problem. I just changed the targetRevision of the Application and it was up and running in a few minutes. Then a few days later things got interesting.
There were no downtimes, but I noticed that Argo started failing to sync itself. Apparently a new minor version of the Helm chart came out (though it was still the same application version) that added support for the networking.k8s.io/v1 version of Ingress. However, it also accidentally broke clusters running Kubernetes before 1.19. And mine was one such.
While the Argo people are figuring out how to fix this (if), I decided to go and take this opportunity to upgrade my cluster. This wasn’t as painless as it should’ve been though.
ErlangはEricssonがはるか昔に開発した通信環境用の言語で、ものすごく頑丈で安定している環境として有名。実際に世界中のモバイル通信環境で用いられ99.9999999% (“nine nines”) の可用性を誇っている。最近ではRuby風でErlangのBEAMを実行環境とするElixirが流行っている印象がある。分散を前提にしている関数型言語としてClojureに近いと感じた。そして実際にBEAMの上でClojureを実装しているものがある。
Clojureが最初はJVMと.NETのCLRも対象にしていたが後JVMだけになり、またClojureScriptの登場でJavaScript上で動くようになった。だから根本的なところは案外実行環境に依存しないところもあるかもしれない。BEAM上でClojureを実装しているClojerlはあくまでもコミュニティーからのもので正式なClojure版ではないが、試したかったBEAMと選べるなら選ぶぐらい好きなClojureが合ったものに当たるから触ってみざるをえなかった。
Was trying to figure out what
zerusski on Clojurians Slackdefrecorddoes in the impl of ILookup it generates and I absolutely do not understand that magic. Essentially it amounts to(get __extmap key)and I can’t even figure out how this magical__extmapgets into scope (a global or some special runtime thing?) andthisisn’t even used. Confused
This post on Clojurians sent me down the rabbit hole looking for where this “mysterious” __extmap comes from. It really isn’t obvious at first, but when I found it, it was “wow” times “duh”.
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。
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.
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.
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.
