Get You a State Machine for Great Good

Andrew Stone of Oxide Engineering joined Bryan, Adam, and the Oxide Friends to talk about his purpose-built, replay debugger for the Oxide setup textual UI. Andrew borrowed a technique from his extensive work with distributed systems to built a UI that was well-structured... and highly amenable to debuggability. He built a custom debugger "in a weekend"! Some of the topics we hit on, in the order that we hit them:tui-rsCrosstermThe reedline crateEpisode about the "Sidecar" switchElm time-travel debuggingReplay.ioDevtools.fm episode on Replay.ioAADEBUG conferenceCalifornia horse meat lawThe (lightly) edited live chat from the show:MattCampbell: I'm gathering that this is more like the fancy pseudo-GUI style of TUI, which is possibly bad for accessibilityahl: we are also building with accessibility in mind, stripping away some of the non-textual elements optionallyMattCampbell: oh, coolahl: Episode about the "Sidecar" switch: https://github.com/oxidecomputer/oxide-and-friends/blob/master/2021_11_29.mdMattCampbell: ooh! That kind of recording is definitely better for accessibility than a video.uwaces: Were you inspired by Elm? (The programming language for web browsers?)bcantrill: Here's Andrew's PR for this, FWIW: oxidecomputer/omicron#2682uwaces: Elm has a very similar model. They have even had a debugger that let you run events in reverse: https://elm-lang.org/news/time-travel-made-easybch: I’m joining late - 1) does this state-machine replay model have a name 2) expand on (describe ) the I/o logic separation distinction?ahl: http://dtrace.org/blogs/ahl/2015/06/22/first-rust-program-pain/zk: RE: logic separation in consensus protocols: the benefit of seperating out the state machine into a side-effect free function allows you to write a formally verified implementation in a pure FP lang or theorem prover, and then extract a reference program from the proof.we're going to the zoo: lol i’m a web dev && we do UI tests via StorybookJS + snapshots of each story + snapshots of the end state of an interactionig: At that point you could turn the recording into an “expect test”. https://blog.janestreet.com/the-joy-of-expect-tests/we're going to the zoo: TOFU but for tests