add slot stats

Author: Faisal Memon

client/nginx.go

@@ -147,6 +147,7 @@ type Slabs map[string]Slab
 // Slab represents slab related stats.
 type Slab struct {
 	Pages Pages
+	Slots Slots
 }
 
 // Pages represents the slab memory usage stats.
@@ -155,6 +156,17 @@ type Pages struct {
 	Free uint64
 }
 
+// Slots is a map of slots by slot size
+type Slots map[string]Slot
+
+// Slot represents slot related stats.
+type Slot struct {
+	Used  uint64
+	Free  uint64
+	Reqs  uint64
+	Fails uint64
+}
+
 // HTTPRequests represents HTTP request related stats.
 type HTTPRequests struct {
 	Total   uint64
@@ -922,12 +934,12 @@ func determineStreamUpdates(updatedServers []StreamUpstreamServer, nginxServers
 func (client *NginxClient) GetStats() (*Stats, error) {
 	info, err := client.getNginxInfo()
 	if err != nil {
-		return nil, fmt.Errorf("failed to get stats %v", err)
+		return nil, fmt.Errorf("failed to get stats: %v", err)
 	}
 
 	slabs, err := client.getSlabs()
 	if err != nil {
-		return nil, fmt.Errorf("failed to get stats %v", err)
+		return nil, fmt.Errorf("failed to get stats: %v", err)
 	}
 
 	cons, err := client.getConnections()