keydb multimaster support (#710)

Co-authored-by: Mihai Craiu <mihai.craiu@1and1.ro>

exporter/info.go

@@ -12,6 +12,29 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+// precompiled regexps
+
+// keydb multimaster
+/*
+master_host:kdb0.server.local
+master_port:6377
+master_1_host:kdb1.server.local
+master_1_port:6377
+*/
+var reMasterHost = regexp.MustCompile(`^master(_[0-9]+)?_host`)
+var reMasterPort = regexp.MustCompile(`^master(_[0-9]+)?_port`)
+var reMasterLinkStatus = regexp.MustCompile(`^master(_[0-9]+)?_link_status`)
+
+// info fieldKey:fieldValue -> metric redis_fieldKey{master_host, master_port} fieldValue
+var reMasterDirect = regexp.MustCompile(`^(master(_[0-9]+)?_(last_io_seconds_ago|sync_in_progress)|slave_repl_offset)`)
+
+// numbered slaves
+/*
+slave0:ip=10.254.11.1,port=6379,state=online,offset=1751844676,lag=0
+slave1:ip=10.254.11.2,port=6379,state=online,offset=1751844222,lag=0
+*/
+var reSlave = regexp.MustCompile(`^slave\d+`)
+
 func extractVal(s string) (val float64, err error) {
 	split := strings.Split(s, "=")
 	if len(split) != 2 {
@@ -67,11 +90,11 @@ func (e *Exporter) extractInfoMetrics(ch chan<- prometheus.Metric, info string,
 
 		keyValues[fieldKey] = fieldValue
 
-		if fieldKey == "master_host" {
+		if reMasterHost.MatchString(fieldKey) {
 			masterHost = fieldValue
 		}
 
-		if fieldKey == "master_port" {
+		if reMasterPort.MatchString(fieldKey) {
 			masterPort = fieldValue
 		}
 
@@ -240,7 +263,7 @@ func parseDBKeyspaceString(inputKey string, inputVal string) (keysTotal float64,
 */
 func parseConnectedSlaveString(slaveName string, keyValues string) (offset float64, ip string, port string, state string, lag float64, ok bool) {
 	ok = false
-	if matched, _ := regexp.MatchString(`^slave\d+`, slaveName); !matched {
+	if !reSlave.MatchString(slaveName) {
 		return
 	}
 	connectedkeyValues := make(map[string]string)
@@ -279,17 +302,21 @@ func parseConnectedSlaveString(slaveName string, keyValues string) (offset float
 
 func (e *Exporter) handleMetricsReplication(ch chan<- prometheus.Metric, masterHost string, masterPort string, fieldKey string, fieldValue string) bool {
 	// only slaves have this field
-	if fieldKey == "master_link_status" {
+	if reMasterLinkStatus.MatchString(fieldKey) {
 		if fieldValue == "up" {
 			e.registerConstMetricGauge(ch, "master_link_up", 1, masterHost, masterPort)
 		} else {
 			e.registerConstMetricGauge(ch, "master_link_up", 0, masterHost, masterPort)
 		}
 		return true
 	}
-	switch fieldKey {
 
-	case "master_last_io_seconds_ago", "slave_repl_offset", "master_sync_in_progress":
+	if reMasterDirect.MatchString(fieldKey) {
+		if strings.HasSuffix(fieldKey, "last_io_seconds_ago") {
+			fieldKey = "master_last_io_seconds_ago"
+		} else if strings.HasSuffix(fieldKey, "sync_in_progress") {
+			fieldKey = "master_sync_in_progress"
+		}
 		val, _ := strconv.Atoi(fieldValue)
 		e.registerConstMetricGauge(ch, fieldKey, float64(val), masterHost, masterPort)
 		return true