Macro collectd_plugin::collectd_log_raw

macro_rules! collectd_log_raw {
    ($lvl:expr, $fmt:expr) => { ... };
    ($lvl:expr, $fmt:expr, $($arg:expr),*) => { ... };
}

A simple wrapper around the collectd’s plugin_log, which in turn wraps vsnprintf.

collectd_log_raw!(LogLevel::Info, b"test %d\0", 10);

Since this is a low level wrapper, prefer CollectdLoggerBuilder or even collectd_log. The only times you would prefer collectd_log_raw:

• Collectd was not compiled with COLLECTD_DEBUG (chances are, your collectd is compiled with debugging enabled) and you are logging a debug message.
• The performance price of string formatting in rust instead of C is too large (this shouldn’t be the case)

Undefined behavior can result from any of the following:

• If the format string is not null terminated
• If any string arguments are not null terminated. Use CString::as_ptr() to ensure null termination
• Malformed format string or mismatched arguments

This expects an already null terminated byte string. In the future once the byte equivalent of concat! is rfc accepted and implemented, this won’t be a requirement. I also wish that we could statically assert that the format string contained a null byte for the last character, but alas, I think we’ve hit brick wall with the current Rust compiler.

For ergonomic reasons, the format string is converted to the appropriate C ffi type from a byte string, but no other string arguments are afforded this luxury (so make sure you convert them).