Is there any default retry middleware running?

[cemoktra]

I have an endpoint that does some heavy data gathering. When i call the endpoint once, i see the endpoint tracing three calls that are invoked exactly after one minute. And then curl times out after 3 minutes. My endpoint itself is not timing out, it never reaches the end. Also my metric middleware does not add any metric, meaning the inner call never succeeded or failed.

My conclusion is, this must be happening somewhere before that. I tried to look through the code but did not yet find anything. I'm not even sure if this relates to axum, hyper or even tower.

But something is going on that i would like to control from axum. Maybe somewhere a budget is added?

Any help or pointing to where some retry layer is added is appreciated.

Thanks

[davidpdrsn]

Nope axum doesn't add any such middleware by default.

Its hard to say without seeing the code. Are you able to make a minimal reproduction script that I can cargo run?

[cemoktra]

I can try next week, I'm off to long weekend without computer already

[cemoktra]

Ok the most simplest code (awaiting a sleep or a blocking sleep) does not reproduce this.

[TmLev]

I'm observing the same behaviour (3 retries) when trying to access a handler with tower_http::timeout::TimeoutLayer from a browser. curl, on the other hand, gave up after the first 408 error.

[TmLev]

Here you go: https://github.com/TmLev/axum-implicit-retry-repro/blob/master/src/main.rs

I tried three different browsers and now I'm actually starting to think that axum and tower has nothing to do with this issue. Looks like each browser has different retry policy (based on my attempts to reproduce aforementioned behaviour):

Browser	Opening page for the first time	Consequent page refreshes
Chrome	1 attempt	3 attempts
Yandex.Browser	3 attempts	3 attempts
Safari	1 attempt	1 attempt

[davidpdrsn]

Yep this seems unrelated to axum and tower. I can confirm that I don't get retries in Safari.

[cemoktra]

With the exception that i did not have a timeout layer

[davidpdrsn]

Gimme a minimal example and I'll take a look.

[cemoktra]

I tried to generate one, but it was not reproducable. It might have to do with concurrency and blocking the handler