chore: add more metrics to redisotel

extra/redisotel/config.go

@@ -5,14 +5,15 @@ import (
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/global"
-	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.12.0"
 	"go.opentelemetry.io/otel/trace"
 )
 
 type config struct {
 	// Common options.
 
-	attrs []attribute.KeyValue
+	dbSystem string
+	attrs    []attribute.KeyValue
 
 	// Tracing options.
 
@@ -51,19 +52,29 @@ func (fn option) metrics() {}
 
 func newConfig(opts ...baseOption) *config {
 	conf := &config{
-		tp: otel.GetTracerProvider(),
-		mp: global.MeterProvider(),
-		attrs: []attribute.KeyValue{
-			semconv.DBSystemRedis,
-		},
+		dbSystem: "redis",
+		attrs:    []attribute.KeyValue{},
+
+		tp:            otel.GetTracerProvider(),
+		mp:            global.MeterProvider(),
 		dbStmtEnabled: true,
 	}
+
 	for _, opt := range opts {
 		opt.apply(conf)
 	}
+
+	conf.attrs = append(conf.attrs, semconv.DBSystemKey.String(conf.dbSystem))
+
 	return conf
 }
 
+func WithDBSystem(dbSystem string) Option {
+	return option(func(conf *config) {
+		conf.dbSystem = dbSystem
+	})
+}
+
 // WithAttributes specifies additional attributes to be added to the span.
 func WithAttributes(attrs ...attribute.KeyValue) Option {
 	return option(func(conf *config) {

extra/redisotel/metrics.go

@@ -82,6 +82,30 @@ func reportPoolStats(rdb *redis.Client, conf *config) error {
 	idleAttrs := append(labels, attribute.String("state", "idle"))
 	usedAttrs := append(labels, attribute.String("state", "used"))
 
+	idleMax, err := conf.meter.AsyncInt64().UpDownCounter(
+		"db.client.connections.idle.max",
+		instrument.WithDescription("The maximum number of idle open connections allowed"),
+	)
+	if err != nil {
+		return err
+	}
+
+	idleMin, err := conf.meter.AsyncInt64().UpDownCounter(
+		"db.client.connections.idle.min",
+		instrument.WithDescription("The minimum number of idle open connections allowed"),
+	)
+	if err != nil {
+		return err
+	}
+
+	connsMax, err := conf.meter.AsyncInt64().UpDownCounter(
+		"db.client.connections.max",
+		instrument.WithDescription("The maximum number of open connections allowed"),
+	)
+	if err != nil {
+		return err
+	}
+
 	usage, err := conf.meter.AsyncInt64().UpDownCounter(
 		"db.client.connections.usage",
 		instrument.WithDescription("The number of connections that are currently in state described by the state attribute"),
@@ -98,14 +122,22 @@ func reportPoolStats(rdb *redis.Client, conf *config) error {
 		return err
 	}
 
+	redisConf := rdb.Options()
 	return conf.meter.RegisterCallback(
 		[]instrument.Asynchronous{
+			idleMax,
+			idleMin,
+			connsMax,
 			usage,
 			timeouts,
 		},
 		func(ctx context.Context) {
 			stats := rdb.PoolStats()
 
+			idleMax.Observe(ctx, int64(redisConf.MinIdleConns))
+			idleMin.Observe(ctx, int64(redisConf.MaxIdleConns))
+			connsMax.Observe(ctx, int64(redisConf.PoolSize))
+
 			usage.Observe(ctx, int64(stats.IdleConns), idleAttrs...)
 			usage.Observe(ctx, int64(stats.TotalConns-stats.IdleConns), usedAttrs...)