token-validator: add a cache when calling wg dump

libadlin/tunnel.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"os/exec"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -26,7 +27,13 @@ type WGDump struct {
 	KeepAlive  string
 }
 
-func readWgDump() (wgd map[string]WGDump, err error) {
+var (
+	wgDumpCache_data  map[string]WGDump = nil
+	wgDumpCache_time  time.Time
+	wgDumpCache_mutex sync.RWMutex
+)
+
+func _readWgDump() (wgd map[string]WGDump, err error) {
 	out, errr := exec.Command("wg", "show", "wg-adlin", "dump").Output()
 
 	if errr != nil {
@@ -46,6 +53,33 @@ func readWgDump() (wgd map[string]WGDump, err error) {
 	return
 }
 
+func readWgDump() (wgd map[string]WGDump, err error) {
+	wgDumpCache_mutex.RLock()
+	defer wgDumpCache_mutex.RUnlock()
+
+	wgd = wgDumpCache_data
+
+	if time.Since(wgDumpCache_time) > time.Second*10 {
+		wgDumpCache_mutex.RUnlock()
+
+		wgDumpCache_mutex.Lock()
+		if time.Since(wgDumpCache_time) > time.Second*10 {
+			wgd, err = _readWgDump()
+			if err != nil {
+				return
+			}
+
+			wgDumpCache_data = wgd
+			wgDumpCache_time = time.Now()
+		}
+		wgDumpCache_mutex.Unlock()
+
+		wgDumpCache_mutex.RLock()
+	}
+
+	return wgd, nil
+}
+
 type TunnelToken struct {
 	token     []byte
 	TokenText string