Update metrics to convert dots

app/ocache/metrics.go

@@ -1,11 +1,18 @@
 package ocache
 
-import "github.com/prometheus/client_golang/prometheus"
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"strings"
+)
 
 func WithPrometheus(reg *prometheus.Registry, namespace, subsystem string) Option {
 	if subsystem == "" {
 		subsystem = "cache"
 	}
+	nameSplit := strings.Split(namespace, ".")
+	subSplit := strings.Split(subsystem, ".")
+	namespace = strings.Join(nameSplit, "_")
+	subsystem = strings.Join(subSplit, "_")
 	if reg == nil {
 		return nil
 	}

app/ocache/metrics_test.go

@@ -0,0 +1,19 @@
+package ocache
+
+import (
+	"context"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+	"strings"
+	"testing"
+)
+
+func TestWithPrometheus_MetricsConvertsDots(t *testing.T) {
+	opt := WithPrometheus(prometheus.NewRegistry(), "some.name", "some.system")
+	cache := New(func(ctx context.Context, id string) (value Object, err error) {
+		return &testObject{}, nil
+	}, opt).(*oCache)
+	_, err := cache.Get(context.Background(), "id")
+	require.NoError(t, err)
+	require.True(t, strings.Contains(cache.metrics.hit.Desc().String(), "some_name_some_system_hit"))
+}