I want to expound on this. Most of our “RPC” and API Elixir services do not have a queue of any sort. Similar to Phoenix, when a web request comes in, a task/process is spawned to handle it. If there are 1000 requests, then 1000 tasks/processes are spawned; nothing is queued.
This works well with Kubernetes and its HPA (horizontal pod autoscaling) feature which is (can be) triggered off of CPU usage.
Starting to extract the notification and reminder system from my Reservations Calendar (https://reservationscalendar.com) to be its own external service.
Mostly feature development for Paraxial.io, published a few blog posts about Elixir/Phoenix security, going deeper on LiveView.
Bumping this thread that I always enjoy reading.
I make optics and build telescopes for a hobby, and surprisingly found myself building my next telescope with Elixir ! This one is special as it will be used as a daytime camera, so it won’t see a star and will work with finite object distances (stars are considered to be at optical infinity).
First, I dug a bit of optical theory and papers (since I don’t have a math background) and wrote small utilities to calculate the best mirror shape for this terrestrial scope. Then, 2D raytracing (in the optical sense, not in the graphics sense) calculations for a parabolic mirror, then a depth of field simulation that allowed me to play a bit more with Rustler.
The project evolved to simulate the future scope with a three.js scene representing the telescope, controlled by a web UI with websockets and a genserver holding and transitioning telescope state.
Now, I’m digging into doing serial from Elixir to communicate with the arduino that will be responsible of moving the physical telescope and live-displaying a picture.
All of this will run on a MangoPi, a small single-core 1GHz RISC-V board. What really excites me is how the current phoenix “telescope simulator” runs on it. Despite the weak single core, I can run a heavy picture generation task in the background taking ~15s while the websocket communicaton stays snappy. Both the background task and the foreground tasks are a bit slowed down, but everything stays responsive on this €25 board.
When I’m done, I’ll do a full write-up on that. Currently preparing a blog post for each step, but it’ll be better to share the whole thing.
So, as of jan 2023, I still think my 2018 decision to go all-in on Elixir was a good one, despite being able to identify what I’d like to be different, or what I’m missing from other languages.
That sounds really cool! Would you mind elaborating more on how you managed to integrate your 3D CAD design with the LiveView simulator and three.js? I’m about to embark on a similar task to use elixir/nerves to control hardware via an Arduino, and I’m looking into ways of showing the current hardware position on the user interface. My friend is supplying the CAD files, so I don’t have much experience with the modeling.
Thanks!
Hi ! I’m not using LiveView here.
Basically, I have a GenServer representing telescope state : current altitude position, current azimuth position. When I click on the UI button to move left in azimuth, a “turn left” event is sent to this GenServer, which enters a loop simulating movement at 0.1deg each 16ms. Each state update is broadcast on the websocket. When I release the button, a “stop moving” event is sent, breaking the loop. This mimics how the physical buttons will be used.
On the UI side, I “just” listen to websocket events and update the rotation of the two scope parts (base moving in azimuth, arm moving in altitude). It’s really rough at the moment and looks like this, but the POC works :
On the physical telescope, I’ll have position encoders (and endstops : I need endstops to avoid a code mistake breaking something) filling this role of updating state, so Elixir will be able to know the absolute position of the telescope.
Recently got vulnerability management shipped in Paraxial.io, here’s the announcement post: Announcing Vulnerability Scanning and Management for Elixir
It tracks findings from Sobelow (application code vulnerabilities), mix deps.audit (for vulnerable dependencies) and mix hex.audit (for dependencies that are retired). There are a few other vendors on the market that do something similar, like Snyk, but that only tracks vulnerable dependencies.
I’ve started to create a location based web app to help locate mobile pharmacies and hospitals for the earthquake that happened in Turkey, on Feb 6th, 2023. Help needed. Thank you.
