Add slave offset metrics

exporter/redis.go

@@ -3,6 +3,7 @@ package exporter
 import (
 	"fmt"
 	"net/url"
+	"regexp"
 	"strconv"
 	"strings"
 	"sync"
@@ -131,6 +132,11 @@ func (e *Exporter) initGauges() {
 		Name:      "master_link_up",
 		Help:      "Master link status on Redis slave",
 	}, []string{"addr", "alias"})
+	e.metrics["connected_slave_offset"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: e.namespace,
+		Name:      "connected_slave_offset",
+		Help:      "Offset of connected slave",
+	}, []string{"addr", "alias", "slave_ip", "slave_state"})
 	e.metrics["db_keys"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
 		Namespace: e.namespace,
 		Name:      "db_keys",
@@ -334,6 +340,36 @@ func parseDBKeyspaceString(db string, stats string) (keysTotal float64, keysExpi
 	return
 }
+/*
+	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
+*/
+func parseConnectedSlaveString(slaveName string, slaveInfo string) (offset float64, ip string, state string, ok bool) {
+	ok = false
+	if matched, _ := regexp.MatchString(`^slave\d+`, slaveName); !matched {
+		return
+	}
+	connectedSlaveInfo := make(map[string]string)
+	for _, kvPart := range strings.Split(slaveInfo, ",") {
+		x := strings.Split(kvPart, "=")
+		if len(x) != 2 {
+			log.Debugf("Invalid format for connected slave string, got: %s", kvPart)
+			return
+		}
+		connectedSlaveInfo[x[0]] = x[1]
+	}
+	offset, err := strconv.ParseFloat(connectedSlaveInfo["offset"], 64)
+	if err != nil {
+		log.Debugf("Can not parse connected slave offset, got: %s", connectedSlaveInfo["offset"])
+		return
+	}
+	ok = true
+	ip = connectedSlaveInfo["ip"]
+	state = connectedSlaveInfo["state"]
+
+	return
+}
+
 func (e *Exporter) extractInfoMetrics(info, addr string, alias string, scrapes chan<- scrapeResult) error {
 	cmdstats := false
 	lines := strings.Split(info, "\r\n")
@@ -376,6 +412,17 @@ func (e *Exporter) extractInfoMetrics(info, addr string, alias string, scrapes c
 			continue
 		}
+		if slaveOffset, slaveIp, slaveState, ok := parseConnectedSlaveString(split[0], split[1]); ok {
+			e.metricsMtx.RLock()
+			e.metrics["connected_slave_offset"].WithLabelValues(
+				addr,
+				alias,
+				slaveIp,
+				slaveState,
+			).Set(slaveOffset)
+			e.metricsMtx.RUnlock()
+		}
+
 		if len(split) != 2 || !includeMetric(split[0]) {
 			continue
 		}

exporter/redis_test.go

@@ -392,6 +392,38 @@ func TestKeyspaceStringParser(t *testing.T) {
 	}
 }
+type slaveData struct {
+	k, v      string
+	ip, state string
+	offset    float64
+	ok        bool
+}
+
+func TestParseConnectedSlaveString(t *testing.T) {
+	tsts := []slaveData{
+		{k: "slave0", v: "ip=10.254.11.1,port=6379,state=online,offset=1751844676,lag=0", offset: 1751844676, ip: "10.254.11.1", state: "online", ok: true},
+		{k: "slave1", v: "offset=1", offset: 1, ok: true},
+		{k: "slave2", v: "ip=1.2.3.4,state=online,offset=123", offset: 123, ip: "1.2.3.4", state: "online", ok: true},
+		{k: "slave", v: "offset=1751844676", ok: false},
+		{k: "slaveA", v: "offset=1751844676", ok: false},
+		{k: "slave0", v: "offset=abc", ok: false},
+	}
+
+	for _, tst := range tsts {
+		if offset, ip, state, ok := parseConnectedSlaveString(tst.k, tst.v); true {
+
+			if ok != tst.ok {
+				t.Errorf("failed for: db:%s stats:%s", tst.k, tst.v)
+				continue
+			}
+
+			if offset != tst.offset || ip != tst.ip || state != tst.state {
+				t.Errorf("values not matching, string:%s   %f %s %s", tst.v, offset, ip, state)
+			}
+		}
+	}
+}
+
 func TestKeyValuesAndSizes(t *testing.T) {
 	e, _ := NewRedisExporter(defaultRedisHost, "test", dbNumStrFull+"="+url.QueryEscape(keys[0]))
@@ -552,7 +584,7 @@ func TestHTTPEndpoint(t *testing.T) {
 		`test_instance_info`,
 		// labels and label values
-		`addr="redis://localhost:6379"`,
+		`addr="redis://` + *redisAddr,
 		`redis_mode`,
 		`standalone`,
 		`cmd="get"`,