Global logger for defmt

[krokosik]

The logging example is nice and all, but in actual use cases, it seems to me that there is no access to the sender object from within for example blocking handlers. Most existing code relies on defmt for logging and it would be nice to define a global handler and not pass around the sender object. I'm fairly new to embedded Rust, so before attempting a deep dive into defmt and postcard-rpc internals, I figured I'd ask as it seems to me like something somebody could have thought about.

So, is there anything that would make it impossible, difficult or plainly pointless?

[jamesmunns]

In general I'm open to adding support.

My suggestion would be to use something like bbqueue or bbq2 to impl a "blocking on one side, async on the other side" byte queue, and send chunks of defmt data to the host to be decoded.

defmt-bbq exists already, but I would suggest looking at bbq2 or some other similar crate that allows for async reception, and then spawn a task that awaits new data and sends it using the sender, on a topic interface.

I plan to write this ~eventually, if you beat me to it, I wouldn't be upset.

[krokosik]

Thanks for the tip! I'll look into implementing it :)

[jamesmunns]

Feel free to let me know if you have any questions, or drop by https://matrix.to/#/#onevariable:matrix.org to chat :)

[jamesmunns]

there is no access to the sender object from within for example blocking handlers.

Also fwiw, you can just stick a clone of the Sender into the Context object, if you need access to it in non-spawn handlers.