[api] add miltierr (#729)

internal/format/format.go

@@ -68,6 +68,24 @@ const (
 	MetricKindMixedPercentiles = "mixed_p"
 )
 
+const (
+	MetricSecond      = "second"
+	MetricMillisecond = "millisecond"
+	MetricMicrosecond = "microsecond"
+	MetricNanosecond  = "nanosecond"
+
+	MetricByte = "byte"
+	/*
+		MetricBit = "bit"
+		MetricKilobyte = "kilobyte"
+		MetricMegabyte = "megabyte"
+		MetricGigabyte = "gigabyte"
+
+		MetricKibibyte = "kibibyte"
+		MetricMebibyte = "mebibyte"
+	*/
+)
+
 // Legacy, left for API backward compatibility
 const (
 	LegacyStringTopTagID      = "skey"
@@ -187,6 +205,7 @@ type MetricMetaValue struct {
 	SkipMinHost          bool            `json:"skip_min_host,omitempty"`
 	SkipSumSquare        bool            `json:"skip_sum_square,omitempty"`
 	PreKeyOnly           bool            `json:"pre_key_only,omitempty"`
+	MetricType           string          `json:"metric_type"`
 
 	RawTagMask          uint32                   `json:"-"` // Should be restored from Tags after reading
 	Name2Tag            map[string]MetricMetaTag `json:"-"` // Should be restored from Tags after reading
@@ -285,6 +304,10 @@ func (m *MetricMetaValue) RestoreCachedInfo() error {
 	if !ValidMetricName(mem.S(m.Name)) {
 		err = multierr.Append(err, fmt.Errorf("invalid metric name: %q", m.Name))
 	}
+	if !IsValidMetricType(m.MetricType) {
+		err = multierr.Append(err, fmt.Errorf("invalid metric type: %s", m.MetricType))
+		m.MetricType = ""
+	}
 
 	if m.Kind == legacyMetricKindStringTop {
 		m.Kind = MetricKindCounter
@@ -902,3 +925,11 @@ func ISO8601Date2BuildDateKey(str string) int32 {
 	}
 	return int32(n) // Will always fit
 }
+
+func IsValidMetricType(typ_ string) bool {
+	switch typ_ {
+	case MetricSecond, MetricMillisecond, MetricMicrosecond, MetricNanosecond, MetricByte, "":
+		return true
+	}
+	return false
+}