The log level format. This can be one of the following:
"ABBR"
: The log level abbreviation in uppercase (e.g.,"INF"
)."FULL"
: The full log level name in uppercase (e.g.,"INFO"
)."L"
: The first letter of the log level in uppercase (e.g.,"I"
)."abbr"
: The log level abbreviation in lowercase (e.g.,"inf"
)."full"
: The full log level name in lowercase (e.g.,"info"
)."l"
: The first letter of the log level in lowercase (e.g.,"i"
).
Alternatively, this can be a function that accepts a log level and returns a string.
The default is "ABBR"
.