There’s a good writeup (plus a library) for period tasks on @sasajuric 's blog - https://www.theerlangelist.com/article/periodic. This approach is very light on infrastructure. If you need full tracking, retry etc then the community seems to lean towards @sorentwo 's Oban project - https://github.com/sorentwo/oban - but that comes with more infrastructure (i.e database) to persist job status etc.

They should be able to give you some inspiration.

You mentioned you were tasked with the project at work; was there any discussion of build-vs-buy? It’s going to be challenging to show the benefits of Elixir when competing with off-the-shelf tools like Pingdom that do this exact job (plus alerting, dashboards, etc) for about 1 US dollar per month per site.

If there are requirements that aren’t served by the market - could be anything from regulatory requirements, to IP filtering on the target sites, to client confidentiality - then make sure your Elixir hype focuses on how it can help solve those unique problems.

A very simple way is using Process.send_after/4. A gen_server can just send itsself a repeating message.

There’s also https://uptimerobot.com/ which is free up to 50 sites and polls your site every 5 minutes. You can get alerts, a 30 day uptime history and response times on the free tier. I’ve been using them for years.

But if you do roll your own, database persistence seems reasonable so you can measure uptime over X time. That would likely mean storing the results in a DB, in which case Oban wouldn’t introduce additional complexity if you’re already using Postgres.

I did a similar project for monitoring, but never had time to finish it to be ready to open source it.

First of all often there aren’t such a thing as best practices in Elixir.
There could be more then one suitable good solution.
That’s one of the beautiful things in Elixir.

In my project for the scheduled “ping” requests it just used Task and TaskSupervisor.

The periodic task in its simplest form (in my opinion):

use Task, restart: :transient

# 60 s
@interval 60 * 1_000

def start_link(_) do
  Task.start_link(&process/0)
end

def process() do
  receive do
  after
    @interval ->
      # do your work here
      IO.inspect "ping"

      process()
  end
end

For storing the registered domains I just used a File which I read at application start.
About the TUI thing I can’t give any suggestions.