Further cleanup

Signed-off-by: Owen Williams <owen.williams@grafana.com>

Author: ywwg

model/metric.go

@@ -33,6 +33,9 @@ var (
 	// names. Note that the IsValidMetricName function performs the same
 	// check but faster than a match with this regular expression.
 	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
+	// NameValidationScheme determines the default method of name validation to be
+	// used. To avoid need for locking, this value should be set once, probably in
+	// an init(), before multiple goroutines are started.
 	NameValidationScheme = LegacyValidation
 )
 
@@ -95,26 +98,9 @@ func (m Metric) FastFingerprint() Fingerprint {
 	return LabelSet(m).FastFingerprint()
 }
 
-// IsValidLegacyMetricName returns true iff name matches the pattern of MetricNameRE
-// for legacy names.
-// This function, however, does not use MetricNameRE for the check but a much
-// faster hardcoded implementation.
-func IsValidLegacyMetricName(n LabelValue) bool {
-	if len(n) == 0 {
-		return false
-	}
-	for i, b := range n {
-		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
-			return false
-		}
-	}
-	return true
-}
-
 // IsValidMetricName returns true iff name matches the pattern of MetricNameRE
-// for legacy names, and iff it's valid UTF-8 if isUtf8 is true.
-// This function, however, does not use MetricNameRE for the check but a much
-// faster hardcoded implementation.
+// for legacy names, and iff it's valid UTF-8 if the UTF8Validation scheme is
+// selected.
 func IsValidMetricName(n LabelValue) bool {
 	switch NameValidationScheme {
 		case LegacyValidation:
@@ -128,3 +114,21 @@ func IsValidMetricName(n LabelValue) bool {
 			panic(fmt.Sprintf("Invalid name validation scheme requested: %d", NameValidationScheme)) 
 	}
 }
+
+// IsValidLegacyMetricName is similar to IsValidMetricName but always uses the
+// legacy validation scheme regardless of the value of NameValidationScheme. It
+// returns true iff name matches the pattern of MetricNameRE for legacy names.
+// This function, however, does not use MetricNameRE for the check but a much
+// faster hardcoded implementation.
+func IsValidLegacyMetricName(n LabelValue) bool {
+	if len(n) == 0 {
+		return false
+	}
+	for i, b := range n {
+		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
+			return false
+		}
+	}
+	return true
+}
+