formatter_glue fails when no unnamed arguments

[r2evans]

Occasionally I forget (i.e., when interactive) to set log_formatter(formatter_json). When this happens, any log messages that use named arguments will be blank. For instance,

log_info(quux="foo", a=pi)
# INFO [2023-11-18 19:50:26] 

where the initial intent was to have this:

log_formatter(formatter_json)
log_info(quux="foo", a=pi)
# INFO [2023-11-18 19:50:54] {"quux":"foo","a":3.1416}

I'm fine with the fact that part of the reason is that I forgot the formatter, but it would be nice if formatter_glue did not drop named arguments. I suggest the names can be dropped, and pasted together (with a space). Something like:

log_formatter(formatter_glue)
log_info(quux="foo", a=pi)
# INFO [2023-11-18 19:52:12] foo 3.14159265358979

---

Edit ... as I'm thinking about this, the purpose and layout of glue is rather simple, where unnamed objects are strings to format, and named objects are variables to use for substitution ... so I think the paste-ing above should only be done when none of ... are unnamed ... or perhaps just assume the first or first character or similar.

Bottom line, having it completely drop the message is perhaps not good. Thoughts?

[r2evans]

Revision: it's extra, yes, but perhaps we create a format string from the names/values of the arguments.

For instance, one of:

log_formatter(formatter_glue)
log_info(quux="a", b=pi)
# INFO [2023-11-19 16:16:23] a 3.14159265358979
##### or
log_info(quux="a", b=pi)
# INFO [2023-11-19 16:16:41] quux=a b=3.14159265358979

While one could play with this type of mechanism for hours, I suggest going anywhere beyond this is too much: the only reason to do any of this is to prevent an empty log entry; if the user wants more control (semi-delimited, quoted strings, whatever) then they should format it the right way the first time.

[r2evans]

More so ... if one does go this one step of auto-adding a simple format string for glue, perhaps there should be a once-per-day warning or message: once to get the point across but not necessarily every single log message.

[daroczig]

Thanks a ton for this report, and I agree that it can be frustrating when this happens 😞

But I'm hesitant to make such overrides in how glue works in its formatted 🤐 And I'd rather keep it a very thin layer on glue, so if it returns nothing for the inputs, we will log nothing:

> str(glue::glue("foo", NULL, quux="a", b=pi))
 'glue' chr(0) 

My suggestion is to check what glue returns, and throw an R warning if the log message was empty. That warnings is printed in the console, so that the user can investigate, and it has it's debouncer (will not show all, but the user can look at the last with warnings()), and logger supports logging warnings as well :)

Please see an example implementation at #147

[r2evans]

I don't see quite how adding a warning is much better than adding a safeguard, but it's your call. Thanks!