testcontainers-rs VS flamegraph

Testing with added infrastructure can be quite tricky. testcontainers aims to solve this by providing an open-source framework for providing local, lightweight containers for your application that can be immediately thrown away after use. It also has a Rust SDK!

Add tests! You can use testcontainers to spin up Docker containers for Postgres and other infrastructure which makes testing your database extremely easy. You can find more about this here.

You didn't mention how do you start Postgres for the tests. Is it assumed it runs in the background? A cool crate I use lately for this kind of thing is test_containers that can start docker containers from code, for example - Postgres

Do you manually spin up the containers or do you use testcontainers?

For the repo testing, that’s simple. https://github.com/testcontainers/testcontainers-rs will start a Docker image and you just use that when instantiating the repo.

Thanks for sharing! I'm still a beginner with Rust and still pretty new to testing in general - is there any benefit to using something like this over bringing up the service as a separate container using something like testcontainers? I suppose the biggest one is this is in-memory and doesn't require the party running tests to have Docker available locally. The tradeoff is the extra work to create all the mocks (i.e. my library has several dozen endpoints).

You can install cargo-flamegraph with cargo install flamegraph. There are some underlying requirements to be able to use cargo-flamegraph; you will want to take a look at the repo here to make sure you have the right dependencies.

I tried to diagnose the issue with flamegraph, but unfortunately the flamegraph didn't show anything beyond the next call for some reason

having some tools to identify slowness origins (flamegraph is one... but not sure it's the way to go)

I'm currently implementing a solution for the first part of the day 16. It work but it is really slow... I'd like to : - understand why - having some tools to identify slowness origins (flamegraph is one... but not sure it's the way to go) - eventually have some clue/solution/idea - have general feedback on what in my "coding style" is not appropriate for rust (I come from java/kotlin/ts even if I've already coded a bit in c/c++) : for example I love iterator & sequence but i feel they are not really suited to overuse in rust (mostly because of async & result).

Use a profiler. Flamegraph is a good way to visualise profiler output. This lets you identify which functions are taking up a large amount of time - and hence helps you identify where to focus your optimisation efforts.

You tried trying to see what takes the most time under load via flames? https://github.com/flamegraph-rs/flamegraph

Well, in cases like that the answer is straight forward, use a profiler like https://github.com/flamegraph-rs/flamegraph

I don't see any obvious problems with your algorithm. I've had luck using cargo-flamegraph to identify the slow parts of my code. That's going to show you which parts to focus on improving the performance of!

From the readme of cargo flamegraph: