ConvertErr converts errors to known types, wrapping the original ones.

CtxWithSyslogLogger attach a logger to the context and set priority based on environment.

ErrNotFoundENoEnt matches NSS status NOTFOUND.

ErrNotFoundSuccess matches NSS status NOTFOUND.

ErrTryAgainEAgain matches NSS status TRYAGAIN.

ErrTryAgainERange matched NSS status ERANGE.

ErrUnavailableENoEnt matches NSS status UNAVAIL.

Logger is the logger connected to syslog.

Option represents the functional option passed to logger.