How can I get a function to run on every loop of axum? (Twilio-rs integration)

[matthiasdebernardini]

I'd like to receive an SMS when my server is down but not run an extra piece of software (some python or shell script), I'd like it to.

There is a crate that implements this so that I only have to run a little bit of configuation code once, then run a function on every nth loop that axum runs. Ideally to call twilio API, like so.

Where would I put this?

I'd actually like this to be part of the axum builder pattern by implementing the tower::Service() trait, is there an example of someone integrating something similar to this? This way I can publish a crate and other's can easily call it.

[davidpdrsn]

What do you mean by "on every nth loop that axum runs". Do you mean run something for every request? If so you need a middleware. See axum::middleware::from_fn

[matthiasdebernardini]

axum is a framework that implements a web server, to implement a server you have to have a while loop somewhere, don't you?

loop {
    if there_is_a_reason_to_stop {
        panic!()
    } else {
        keep_running()
    }
}

so when that loop runs (if it does run at all - if this is not the case then I need to study axum better) I'd like it to check additional conditions as well

[davidpdrsn]

You mean graceful shutdown?

[matthiasdebernardini]

Actually, I think this is what I would need to implement. https://docs.rs/hyper/0.14.26/hyper/server/struct.Builder.html

[davidpdrsn]

Are you saying you want to implement your own server builder? Not sure what you mean 😅

[matthiasdebernardini]

My apologies,

I want to configure and add this functionality using the builder pattern, like so;

    let twilio = configure(params);

    Server::bind(&addr)
        .add_extra_thing(twilio)
        .serve(service)
        .await
        .expect("server failed");

[davidpdrsn]

What would .add_extra_thing(twilio) do?

[davidpdrsn]

You can run other async things concurrently using tokio::spawn if that's what you want.

[matthiasdebernardini]

add_extra_thing(twilio) would create an http Client struct, connect to the API and make an http get request periodically, at some time interval in my case.

That makes sense to use that, thanks.