Podman containers can’t talk to each other

The other day I decided to update my server-side rendering example, and I ran into a strange problem. While my compose.yaml hasn’t changed, my containers could not talk to each other. This was most apparent with the nginx container, which immediately crashed out with [emerg] 1#1: host not found in upstream. What gives?

After a quick debugging including on a different computer, it became clear that my compose.yaml should be fine: it worked without issues on the computer that used Docker, but didn’t work with Podman. The issue with Podman was soon clear too: looking at podman network inspect the "dns_enabled": false was an obvious culprit. That’s where things got interesting.


2024を振り返ろう

2024はあまりいい味が残る年にはならなかった。始まりはいいものの、そのあとは負の連鎖が続くという感じでなかなか評価が厳しい。


Tricking the JVM JIT into speed

On the Clojurians Slack, PEZ brought some delicious Fibonacci performance tuning from the “languages” repo. While I don’t think that benchmark is as useful as mesmerizing the moving circles are in the animated graphs, I had a few very confusing and interesting discoveries.

Step 1: watch Alex Miller’s talk about Clojure’s interop performance. Step 2: learn how to actually do all that stuff. Step 3: notice that recursion does things. Step 4: magic.


Untyped JS objects in ClojureScript

Working on a Chrome plugin I got to use ClojureScript in yet another new environment. After the usual browser setup, Node, Deno and Github Actions, this time it was the Chrome plugin system. While it was mostly a very smooth ride, I had a little trouble figuring out how to deal with a “Cannot infer target type in expression” warning.

It showed up while dealing with a HAR entry object passed in to my callback from devtools.network.onRequestFinished. The HAR object, while its shape is well defined, is not typed in a strict sense (though I guess there may be some type definition for it somewhere out there if I looked hard enough). That’s why when I tried to access its fields like (-> entry .-request .-url) the ClojureScript compiler (through Shadow CLJS) would complain about inferring the “target type” as above.


ClojureDartで自前でwidget作ろうとするときの注意点

やりたかったことは多言語対応の一環だった。flutter_localizationsの生成コードでBuildContextからAppLocalizationは取得できるが、それと別にOSの言語設定を監視したかった。そのために他のウィジェットを包むだけのものを用意して、ミドルウェア的な挙動でOSの言語設定をアプリのDBに保管したかった。でもなぜかそれを適応すると、今度はgo_routerのStatefulShellRouteを使った遷移が機能しなくなってしまった。


HTTP Signatures are RFC

If you’ve worked with Mastodon (or possibly other ActivityPub implementations too) HTTP Signatures might sound familiar. When notifying another server of an event, the request can be signed thus proving its authenticity, meaning that the receiving server doesn’t need to go and fetch the authoritative version from the origin. This reduces load on both the receiver of the event (less requests to send) and the origin (less requests to serve).

black audio mixer

extend-protocolでClass/forName怒られるワケ

Clojureでプロトコルをよく使う。defprotocolで作ってextend-protocolで各種の型に実装すると、いろんな入力値にスムーズに対応できる。例えば暗号化周りで、ハッシュや署名の算出のためにバイト配列が必要な際、プロトコルを活かしていい感じのAPIが提供できる。

(defprotocol Byteish
  (->bytes ^bytes [input]))

(extend-protocol Byteish
  String
  (->bytes [input] (.getBytes input)))

Why isn’t my HTTP/3 working?

On a sudden impulse, today I updated the Traefik in my cluster to v3. Unlike the transition from v1 to v2, v2 to v3 was very smooth. I only needed a few tiny tweaks to the configuration. One of those was that HTTP/3 support is no longer “experimental” and so it shouldn’t be configured as such. This started me on a weird quest on getting my sites to use H3.


Anime weekend

Friday I was just spacing out looking at some AMV on Youtube when I noticed a shot from Dragon Maid. It’s been a while since I last (re-)watched that, so I decided to enjoy some delicious slice-of-life sakuga.

By the time I realized what’s happening I’d speedrun both seasons of Dragon Maid and it was time for more. Mahoushoujo ni Akogarete has been on my to-watch list for a while, and I took this opportunity to actually watch it end to end. It was… well, a not exactly safe-for-work experience, but especially the close-ups of Baiser’s face are absolute cinema.


Magic

A while back I picked up my fretless Ibanez to practice some old-school songs. Think Elvis, Cream, Stray Cats or Blue Cheer. I use the fretless even if the original wasn’t played on one, because otherwise I’d pretty much never pick it up. I still do so sadly infrequently…

So it was quite a shock that the bass’s neck was so bowed that it was unplayable (strings touching the fretboard all along). At that point I didn’t have time to learn how to fix it (by adjusting the rod inside) so I put it back into its case and kinda forgot about it.

Then today after cleaning my room I gathered the tools I needed and took it out of the case to fix it—except it was back to normal. I can only assume that the bending was caused by the ridiculous humidity and summer heat, especially during the weeks in June while I was on Denali (and so the AC in the room was off), and then it gradually returned to normal.

To celebrate I played until my fingers started to ache (which isn’t a lot of time considering how out of routine I am).