custom logger

[plebhash]

background

protocols crates should use as little external dependencies as possible.

problem

currently, the following crates use tracing as an external dependency:

• sv1_api
• binary_sv2
• codec_sv2
• roles_logic_sv2

solution

write a custom logger to replace tracing

reference from rust-lightning: https://github.com/lightningdevkit/rust-lightning/blob/f94bf9861289ce6a75fd7d5856d736a2f966a619/lightning/src/util/logger.rs#L165

[Fi3]

tracing is kinda of the standard for logging, every project that will use the library will very likely expect to have log reported by tracing, is also audited by google. https://github.com/google/rust-crate-audits/blob/main/manual-sources/google3-audits.toml#L1383

I don't think that we should remove it, if there is a way to do that without disrupting the user experience could make sense. If not no.

[Shourya742]

https://carbonated-machine-4e3.notion.site/Custom-Logger-878dbdf54d154ad68890c98814df707c

[plebhash]

I should probably clarify that I only created this issue to take note of some discussion point we had in a call last year

even though we try to use as little external dependencies as possible (to avoid introducing vulnerabilities etc), tracing is a widely used crate, and as @Fi3 pointed out it's extensively audited and therefore I don't see this dependency as a critical point of vulnerability

therefore I don't think this is high priority

[Shourya742]

I have implemented a custom logger, which can be found here: https://github.com/Shourya742/logger. I'm leaving this comment in case we might need it in the future.

[plebhash]

@Georges760 please write an explanation of how embedded systems manage logging

[Georges760]

@Georges760 please write an explanation of how embedded systems manage logging

In embedded systems, logging is usually done using defmt crate (more info here), it permit "deferred formatting", so the microcontroler does not have to manipulate utf8 strings and send them to the host debugger !

Most of the libraries that want to support embedded system have a feature defmt or often defmt-03 that

• enable the optional dependancy (ex serde-json-core)
• propagate to dep with defmt support
• add #[cfg_attr(feature = "defmt-03", derive(defmt::Format))] to pub struct/enum of the crate (ex serde-json-core)

As defmt optimization rely on linker time specific, it MUST be opt-in for a library (so does any logging system IMHO to let the library user choose which logging system to use).

As an example, in bm13xx-rs crates, I have support for 2 logging systems: defmt (for embedded) or log (for std), and have an abstraction here so the code can use the usual debug!() and other info!()`.