etcd 日志级别

const (  
    // CRITICAL is the lowest log level; only errors which will end the program will be propagated.
    CRITICAL LogLevel = iota - 1
    // ERROR is for errors that are not fatal but lead to troubling behavior.
    ERROR
    // WARNING is for errors which are not fatal and not errors, but are unusual. Often sourced from misconfigurations.
    WARNING
    // NOTICE is for normal but significant conditions.
    NOTICE
    // INFO is a log level for common, everyday log updates.
    INFO
    // DEBUG is the default hidden level for more verbose updates about internal processes.
    DEBUG
    // TRACE is for (potentially) call by call tracing of programs.
    TRACE
)

switch l {  
    case CRITICAL:
        return "C"
    case ERROR:
        return "E"
    case WARNING:
        return "W"
    case NOTICE:
        return "N"
    case INFO:
        return "I"
    case DEBUG:
        return "D"
    case TRACE:
        return "T"
    default:
        panic("Unhandled loglevel")
    }