How to debug Rust code with Flutter?

[ivan-sirosh]

Since Rust code is compiled and run by Flutter, it is not possible to put any brakepoint in the Rust code.
Is there any way to run Rust part of program independent of Flutter part and still communicate between them?

[temeddix]

Hi @ivan-sirosh , that's an interesting viewpoint for debugging that I didn't think about before.

I don't think using Rust breakpoints in a Flutter app is possible. Instead, using #[test] attributes with cargo test might allow you to use breakpoints in test functions, though it cannot communicate with Flutter.

If you have some new ideas or opinions, please let me know!

[ivan-sirosh]

The idea behind to allow to run rust code independently. The protobuf communicates by gRPC (socket port is opened) or by HTTP, what does not matter in that case.

I would like to have some debug parameter to connect to remote protobuf host instead of default which is spawn by frlutter -> rust.

It will allows me to develop backend with real frontend in use.

Something line like run Rust code with brake points in the IDE and meanwhile run flutter app to execute real call to gRPC bridge.

[temeddix]

I see, but I do see one caveat. It's that Rust tasks are exeucted in parallel concurrency system(async).

If you have 16 cores on your PC, Rust tasks will be executed in 16 threads when using Rinf(by tokio). If you have a breakpoint in one of your Rust functions, it might be able to block on that particular thread, but other threads will keep on working.

If you want to check debug parameters, is the debug_print!() macro insufficient? If not, could you elaborate why it is not suitable?

• https://rinf-docs.cunarist.com/writing-code/#the-debug_print-macro

Or, would sending custom development signals to Rust be helpful(via keyboard events, etc)?

P.S. In Rinf, protobuf is used only for serial/deserialization. Sending data between Dart and Rust is done by native ABI.