refactor: combine functions into one file

since these functions like GetDevID, GetNodeIP ..., they all related
to the host system info, just move them into one file, and easy to
controll.

Signed-off-by: Ace-Tang <[email protected]>

pkg/system/system.go

@@ -0,0 +1,131 @@
+package system
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"net"
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+// file to check to determine Operating System
+const etcOsRelease = "/etc/os-release"
+
+// getSysInfo gets sysinfo.
+func getSysInfo() (*syscall.Sysinfo_t, error) {
+	si := &syscall.Sysinfo_t{}
+	err := syscall.Sysinfo(si)
+	if err != nil {
+		return nil, err
+	}
+	return si, nil
+}
+
+// GetTotalMem gets total ram of host.
+func GetTotalMem() (uint64, error) {
+	si, err := getSysInfo()
+	if err != nil {
+		return 0, err
+	}
+	return si.Totalram, nil
+}
+
+// GetDevID returns device id via syscall according to the input directory.
+func GetDevID(dir string) (uint64, error) {
+	var st syscall.Stat_t
+	if err := syscall.Stat(dir, &st); err != nil {
+		return 0, errors.Wrapf(err, "failed to get device id of directory: (%s)", dir)
+	}
+	return st.Dev, nil
+}
+
+// GetSerialNumber gets serial number or a machine.
+func GetSerialNumber() string {
+	var sn string
+	if b, e := exec.Command("dmidecode", "-s", "system-serial-number").CombinedOutput(); e == nil {
+		scanner := bufio.NewScanner(bytes.NewReader(b))
+		for scanner.Scan() {
+			sn = scanner.Text()
+		}
+	}
+	if len(strings.Fields(sn)) != 0 {
+		sn = strings.Fields(sn)[0]
+	}
+	for i := 0; i < 10; i++ {
+		if _, ex := os.Stat("/usr/alisys/dragoon/libexec/armory/bin/armoryinfo"); ex == nil {
+			if b, e := exec.Command("/usr/alisys/dragoon/libexec/armory/bin/armoryinfo", "sn").CombinedOutput(); e == nil {
+				sn = strings.TrimSpace(string(b))
+			}
+		}
+		if sn != "" {
+			break
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	return sn
+}
+
+// GetNodeIP fetches node ip via command hostname.
+// If it fails to get this, return empty string directly.
+func GetNodeIP() string {
+	output, err := exec.Command("hostname", "-i").CombinedOutput()
+	if err != nil {
+		return ""
+	}
+
+	scanner := bufio.NewScanner(bytes.NewReader(output))
+	for scanner.Scan() {
+		ip := scanner.Text()
+		if net.ParseIP(ip) != nil {
+			return ip
+		}
+	}
+	return ""
+}
+
+// GetOSName gets data in /etc/os-release and gets OS name.
+// For example, in a Ubuntu host, fetched data are like:
+// root@i-8brpbc9t:~# cat /etc/os-release
+// NAME="Ubuntu"
+// VERSION="16.04.2 LTS (Xenial Xerus)"
+// ID=ubuntu
+// ID_LIKE=debian
+// PRETTY_NAME="Ubuntu 16.04.2 LTS"
+// VERSION_ID="16.04"
+// HOME_URL="http://www.ubuntu.com/"
+// SUPPORT_URL="http://help.ubuntu.com/"
+// BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
+// VERSION_CODENAME=xenial
+// UBUNTU_CODENAME=xenial
+func GetOSName() (string, error) {
+	etcOsReleaseFile, err := os.Open(etcOsRelease)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return "", fmt.Errorf("failed to open %s: %v", etcOsRelease, err)
+		}
+	}
+	defer etcOsReleaseFile.Close()
+
+	var prettyName string
+
+	scanner := bufio.NewScanner(etcOsReleaseFile)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.HasPrefix(line, "PRETTY_NAME=") {
+			continue
+		}
+
+		data := strings.SplitN(line, "=", 2)
+		prettyName = data[1]
+		return prettyName, nil
+	}
+
+	return "Linux", nil
+
+}