Provide remote log read capability

[taunusflieger]

No description provided.

[Vollbrecht]

there was a way presented around 2 months ago in the matrix chat iirc ( end of october), where you could siphon the log output and still dont loose the local log.

    use core::ffi::{c_char, c_int};
    use esp_idf_sys::{size_t, va_list};
    use log::info;

    extern "C" {
        #[allow(improper_ctypes)]
        pub fn vsnprintf(_: *mut c_char, _: size_t, _: *const c_char, _: va_list) -> c_int;
    }

    #[allow(improper_ctypes_definitions)]
    unsafe extern "C" fn vprintf_trampoline(arg1: *const c_char, arg2: va_list) -> c_int {
        const MAX_LEN: usize = 128;
        let mut buf = [0u8; MAX_LEN];
        let len = vsnprintf(buf.as_mut_ptr() as _, MAX_LEN as _, arg1, arg2);
        if len < 0 {
            info!("vsnprintf returned an error: {len}");
            return len;
        }
        let s = &buf[0..(len as usize).min(MAX_LEN)]; // the min is just in case
        match core::str::from_utf8(s) {
            Ok(s) => info!("esp log received: {s}"),
            Err(err) => info!("esp log received a non-utf8 string: {err}, {s:?}"),
        }
        len
    }
    unsafe { esp_idf_sys::esp_log_set_vprintf(Some(vprintf_trampoline)) };
    esp_idf_svc::log::EspLogger::initialize_default();

hope this helps