feat(smalltrip,exceptions): Severity type implementation

smalltrip/exceptions/severity.go

@@ -0,0 +1,73 @@
+package exceptions
+
+import (
+	"encoding"
+	"fmt"
+)
+
+type Severity int
+
+var (
+	_ fmt.Stringer             = (Severity)(0)
+	_ encoding.TextMarshaler   = (Severity)(0)
+	_ encoding.TextUnmarshaler = (*Severity)(nil)
+)
+
+const (
+	DEBUG Severity = -4
+	INFO  Severity = 0
+	WARN  Severity = 4
+	ERROR Severity = 8
+	FATAL Severity = 16
+
+	stringDEBUG = "DEBUG"
+	stringINFO  = "INFO"
+	stringWARN  = "WARN"
+	stringERROR = "ERROR"
+	stringFATAL = "FATAL"
+
+	stringUNDEFINED = "UNDEFINED"
+)
+
+func (s Severity) String() string {
+	switch s {
+	case DEBUG:
+		return stringDEBUG
+	case INFO:
+		return stringINFO
+	case WARN:
+		return stringWARN
+	case ERROR:
+		return stringERROR
+	case FATAL:
+		return stringFATAL
+	default:
+		return fmt.Sprintf(stringUNDEFINED)
+	}
+}
+
+func (s Severity) MarshalText() ([]byte, error) {
+	str := s.String()
+	if str == stringUNDEFINED {
+		return nil, fmt.Errorf("severity of value %q does not exists", s)
+	}
+	return []byte(str), nil
+}
+
+func (s *Severity) UnmarshalText(text []byte) error {
+	switch string(text) {
+	case stringDEBUG:
+		*s = DEBUG
+	case stringINFO:
+		*s = INFO
+	case stringWARN:
+		*s = WARN
+	case stringERROR:
+		*s = ERROR
+	case stringFATAL:
+		*s = FATAL
+	default:
+		return fmt.Errorf("severity level %d does not exists", s)
+	}
+	return nil
+}