Module GELF::Levels
In: lib/gelf/severity.rb

There are two things you should know about log levels/severity: 

 - syslog defines levels from 0 (Emergency) to 7 (Debug).
   0 (Emergency) and 1 (Alert) levels are reserved for OS kernel.
 - Ruby default Logger defines levels from 0 (DEBUG) to 4 (FATAL) and 5 (UNKNOWN).
   Note that order is inverted.

For compatibility we define our constants as Ruby Logger, and convert values before generating GELF message, using defined mapping.

Constants

DEBUG = 0
INFO = 1
WARN = 2
ERROR = 3
FATAL = 4
UNKNOWN = 5
EMERGENCY = 10   Additional native syslog severities. These will work in direct mapping mode only, for compatibility with syslog sources unrelated to Logger.
ALERT = 11
CRITICAL = 12
WARNING = 14
NOTICE = 15
INFORMATIONAL = 16

[Validate]