feat: Add config metrics for Sentinel instances (#1058)

* feat: Add config metrics for Sentinel instances

* update sentinel test case

Author: destinyoooo

exporter/exporter.go

@@ -563,6 +563,8 @@ func NewRedisExporter(uri string, opts Options) (*Exporter, error) {
 		"sentinel_scripts_queue_length":                      {txt: "Queue of user scripts to execute"},
 		"sentinel_simulate_failure_flags":                    {txt: "Failures simulations"},
 		"sentinel_tilt":                                      {txt: "Sentinel is in TILT mode"},
+		"sentinel_config_key_value":                          {txt: `Sentinel global config key and value`, lbls: []string{"key", "value"}},
+		"sentinel_config_value":                              {txt: `Sentinel global config key and value as metric`, lbls: []string{"key"}},
 		"slave_info":                                         {txt: "Information about the Redis slave", lbls: []string{"master_host", "master_port", "read_only"}},
 		"slave_repl_offset":                                  {txt: "Slave replication offset", lbls: []string{"master_host", "master_port"}},
 		"slowlog_last_id":                                    {txt: `Last id of slowlog`},
@@ -882,6 +884,8 @@ func (e *Exporter) scrapeRedisHost(ch chan<- prometheus.Metric) error {
 
 	if strings.Contains(infoAll, "# Sentinel") {
 		e.extractSentinelMetrics(ch, c)
+
+		e.extractSentinelConfig(ch, c)
 	}
 
 	if e.options.ExportClientList {

exporter/sentinels.go

@@ -96,6 +96,43 @@ func (e *Exporter) extractSentinelMetrics(ch chan<- prometheus.Metric, c redis.C
 	}
 }
 
+func (e *Exporter) extractSentinelConfig(ch chan<- prometheus.Metric, c redis.Conn) {
+	if !e.options.InclConfigMetrics {
+		return
+	}
+	sentinelConfig, err := redis.Values(doRedisCmd(c, "SENTINEL", "config", "get", "*"))
+	if err != nil {
+		log.Errorf("Error getting sentinel config: %s", err)
+		return
+	}
+
+	if len(sentinelConfig)%2 != 0 {
+		log.Errorf("Invalid sentinel config, got: %#v", sentinelConfig)
+		return
+	}
+
+	log.Debugf("Sentinel config: %v", sentinelConfig)
+
+	for pos := 0; pos < len(sentinelConfig)/2; pos++ {
+		strKey, err := redis.String(sentinelConfig[pos*2], nil)
+		if err != nil {
+			log.Errorf("invalid sentinel config key name, err: %s, skipped", err)
+			continue
+		}
+
+		strVal, err := redis.String(sentinelConfig[pos*2+1], nil)
+		if err != nil {
+			log.Debugf("invalid sentinel config value for key name %s, err: %s, skipped", strKey, err)
+			continue
+		}
+
+		e.registerConstMetricGauge(ch, "sentinel_config_key_value", 1.0, strKey, strVal)
+		if val, err := strconv.ParseFloat(strVal, 64); err == nil {
+			e.registerConstMetricGauge(ch, "sentinel_config_value", val, strKey)
+		}
+	}
+}
+
 func (e *Exporter) processSentinelSentinels(ch chan<- prometheus.Metric, sentinelDetails []interface{}, labels ...string) {
 
 	// If we are here then this master is in ok state

exporter/sentinels_test.go

@@ -2,6 +2,7 @@ package exporter
 
 import (
 	"fmt"
+	"net/http/httptest"
 	"os"
 	"strings"
 	"testing"
@@ -356,3 +357,34 @@ func TestSentinelScrapeRedisHostSentinelPath(t *testing.T) {
 		t.Error("Expected to find sentinel metrics when scraping sentinel host via scrapeRedisHost()")
 	}
 }
+
+func TestSentinelScrapeAllConfig(t *testing.T) {
+	if os.Getenv("TEST_VALKEY_SENTINEL_URI") == "" {
+		t.Skipf("TEST_VALKEY_SENTINEL_URI not set - skipping")
+	}
+	addr := os.Getenv("TEST_VALKEY_SENTINEL_URI")
+	for _, inc := range []bool{false, true} {
+		e, _ := NewRedisExporter(
+			addr,
+			Options{Namespace: "test",
+				InclConfigMetrics: inc,
+			},
+		)
+
+		ts := httptest.NewServer(e)
+		defer ts.Close()
+
+		body := downloadURL(t, ts.URL+"/metrics")
+		for _, want := range []string{
+			"sentinel_config_key_value",
+			"sentinel_config_value",
+		} {
+			if inc && !strings.Contains(body, want) {
+				t.Fatalf("didn't find metrics with sentinel_config, want: %s, body: %s", want, body)
+				return
+			} else if !inc && strings.Contains(body, want) {
+				t.Errorf("did NOT want metrics to include sentinel_config, have:\n%s", body)
+			}
+		}
+	}
+}