Merge pull request #194 from cgroschupp/add_slowlog_last_id

Add slowlog_last_id metric.

exporter/redis.go

@@ -200,6 +200,11 @@ func (e *Exporter) initGauges() {
 		Name:      "slowlog_length",
 		Help:      "Total slowlog",
 	}, []string{"addr", "alias"})
+	e.metrics["slowlog_last_id"] = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: e.namespace,
+		Name:      "slowlog_last_id",
+		Help:      "Last id of slowlog",
+	}, []string{"addr", "alias"})
 }
 // splitKeyArgs splits a command-line supplied argument into a slice of dbKeyPairs.
@@ -874,6 +879,20 @@ func (e *Exporter) scrapeRedisHost(scrapes chan<- scrapeResult, addr string, idx
 		e.metricsMtx.RUnlock()
 	}
+	if values, err := redis.Values(c.Do("SLOWLOG", "GET", "1")); err == nil {
+		var slowlogLastId int64 = 0
+
+		if len(values) > 0 {
+			if values, err = redis.Values(values[0], err); err == nil && len(values) > 0 {
+				slowlogLastId = values[0].(int64)
+			}
+		}
+
+		e.metricsMtx.RLock()
+		e.metrics["slowlog_last_id"].WithLabelValues(addr, e.redis.Aliases[idx]).Set(float64(slowlogLastId))
+		e.metricsMtx.RUnlock()
+	}
+
 	log.Debugf("scrapeRedisHost() done")
 	return nil
 }

exporter/redis_test.go

@@ -105,6 +105,53 @@ func resetLatency(t *testing.T, addr string) error {
 	return nil
 }
+func setupSlowLog(t *testing.T, addr string) error {
+	c, err := redis.DialURL(addr)
+	if err != nil {
+		t.Errorf("couldn't setup redis, err: %s ", err)
+		return err
+	}
+	defer c.Close()
+
+	_, err = c.Do("CONFIG", "SET", "SLOWLOG-LOG-SLOWER-THAN", 10000)
+	if err != nil {
+		t.Errorf("couldn't setup redis, err: %s ", err)
+		return err
+	}
+
+	// Have to pass in the sleep time in seconds so we have to divide
+	// the number of milliseconds by 1000 to get number of seconds
+	_, err = c.Do("DEBUG", "SLEEP", TimeToSleep/1000.0)
+	if err != nil {
+		t.Errorf("couldn't setup redis, err: %s ", err)
+		return err
+	}
+
+	time.Sleep(time.Millisecond * 50)
+
+	return nil
+}
+
+func resetSlowLog(t *testing.T, addr string) error {
+
+	c, err := redis.DialURL(addr)
+	if err != nil {
+		t.Errorf("couldn't setup redis, err: %s ", err)
+		return err
+	}
+	defer c.Close()
+
+	_, err = c.Do("SLOWLOG", "RESET")
+	if err != nil {
+		t.Errorf("couldn't setup redis, err: %s ", err)
+		return err
+	}
+
+	time.Sleep(time.Millisecond * 50)
+
+	return nil
+}
+
 func downloadUrl(t *testing.T, url string) []byte {
 	log.Debugf("downloadURL() %s", url)
 	resp, err := http.Get(url)
@@ -167,6 +214,87 @@ func TestLatencySpike(t *testing.T) {
 	}
 }
+func TestSlowLog(t *testing.T) {
+	e, _ := NewRedisExporter(defaultRedisHost, "test", "", "")
+
+	chM := make(chan prometheus.Metric)
+	go func() {
+		e.Collect(chM)
+		close(chM)
+	}()
+
+	oldSlowLogId := float64(0)
+
+	for m := range chM {
+		switch m := m.(type) {
+		case prometheus.Gauge:
+			if strings.Contains(m.Desc().String(), "slowlog_last_id") {
+				got := &dto.Metric{}
+				m.Write(got)
+
+				oldSlowLogId = got.GetGauge().GetValue()
+			}
+		}
+	}
+
+	setupSlowLog(t, defaultRedisHost.Addrs[0])
+	defer resetSlowLog(t, defaultRedisHost.Addrs[0])
+
+	chM = make(chan prometheus.Metric)
+	go func() {
+		e.Collect(chM)
+		close(chM)
+	}()
+
+	for m := range chM {
+		switch m := m.(type) {
+		case prometheus.Gauge:
+			if strings.Contains(m.Desc().String(), "slowlog_last_id") {
+				got := &dto.Metric{}
+				m.Write(got)
+
+				val := got.GetGauge().GetValue()
+
+				if oldSlowLogId > val {
+					t.Errorf("no new slowlogs found")
+				}
+			}
+			if strings.Contains(m.Desc().String(), "slowlog_length") {
+				got := &dto.Metric{}
+				m.Write(got)
+
+				val := got.GetGauge().GetValue()
+				if val == 0 {
+					t.Errorf("slowlog length is zero")
+				}
+			}
+		}
+	}
+
+	resetSlowLog(t, defaultRedisHost.Addrs[0])
+
+	chM = make(chan prometheus.Metric)
+	go func() {
+		e.Collect(chM)
+		close(chM)
+	}()
+
+	for m := range chM {
+		switch m := m.(type) {
+		case prometheus.Gauge:
+			if strings.Contains(m.Desc().String(), "slowlog_length") {
+				got := &dto.Metric{}
+				m.Write(got)
+
+				val := got.GetGauge().GetValue()
+				if val != 0 {
+					t.Errorf("Slowlog was not reset")
+				}
+			}
+		}
+	}
+}
+
 func setupDBKeys(t *testing.T, addr string) error {
 	c, err := redis.DialURL(addr)
@@ -345,6 +473,7 @@ func TestExporterMetrics(t *testing.T) {
 		"config_maxmemory",  // testing config extraction
 		"config_maxclients", // testing config extraction
 		"slowlog_length",
+		"slowlog_last_id",
 		"start_time_seconds",
 		"uptime_in_seconds",
 	}