feat: add system info page (#1033)

* feat: add system info page

* feat: add some code

* fix

util/system.go

@@ -0,0 +1,78 @@
+// Copyright 2022 The Casdoor Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"io/ioutil"
+	"os"
+	"runtime"
+	"strings"
+	"time"
+
+	"github.com/shirou/gopsutil/cpu"
+	"github.com/shirou/gopsutil/mem"
+)
+
+// get cpu usage
+func GetCpuUsage() ([]float64, error) {
+	usage, err := cpu.Percent(time.Second, true)
+	return usage, err
+}
+
+var fileDate, version string
+
+// get memory usage
+func GetMemoryUsage() (uint64, uint64, error) {
+	virtualMem, err := mem.VirtualMemory()
+	if err != nil {
+		return 0, 0, err
+	}
+
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	return m.TotalAlloc, virtualMem.Total, nil
+}
+
+// get github repo release version
+func GetGitRepoVersion() (string, error) {
+	pwd, err := os.Getwd()
+	if err != nil {
+		return "", err
+	}
+
+	fileInfos, err := ioutil.ReadDir(pwd + "/.git/refs/heads")
+	for _, v := range fileInfos {
+		if v.Name() == "master" {
+			if v.ModTime().String() == fileDate {
+				return version, nil
+			} else {
+				fileDate = v.ModTime().String()
+				break
+			}
+		}
+	}
+
+	content, err := ioutil.ReadFile(pwd + "/.git/refs/heads/master")
+	if err != nil {
+		return "", err
+	}
+
+	// Convert to full length
+	temp := string(content)
+	version = strings.ReplaceAll(temp, "\n", "")
+
+	return version, nil
+}