formating and text fixes, adjust regexp

config/config.go

@@ -31,7 +31,7 @@ var (
 	patFileSDName = regexp.MustCompile(`^[^*]*(\*[^/]*)?\.(json|yml|yaml|JSON|YML|YAML)$`)
 	patRulePath   = regexp.MustCompile(`^[^*]*(\*[^/]*)?$`)
 	patAuthLine   = regexp.MustCompile(`((?:password|bearer_token|secret_key|client_secret):\s+)(".+"|'.+'|[^\s]+)`)
-	relabelTarget = regexp.MustCompile(`^(?:(?:[a-zA-Z_]|\$\{?[\w]+\}?)+\w*)+$`)
+	relabelTarget = regexp.MustCompile(`^(?:(?:[a-zA-Z_]|\$(?:\{\w+\}|\w+))+\w*)+$`)
 )
 
 // Load parses the YAML input s into a Config.
@@ -987,8 +987,8 @@ type RelabelConfig struct {
 	Regex Regexp `yaml:"regex,omitempty"`
 	// Modulus to take of the hash of concatenated values from the source labels.
 	Modulus uint64 `yaml:"modulus,omitempty"`
-	// The label to which the resulting string is written in a replacement.
-	// regex interpolation is allowed for the replace action.
+	// TargetLabel is the label to which the resulting string is written in a replacement.
+	// Regexp interpolation is allowed for the replace action.
 	TargetLabel string `yaml:"target_label,omitempty"`
 	// Replacement is the regex replacement pattern to be used.
 	Replacement string `yaml:"replacement,omitempty"`