Added uptime functionality

internal/uptime/linux_uptime.go

@@ -0,0 +1,50 @@
+//go:build linux
+
+package uptime
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func getLinuxUptime() (UptimeInformation, error) {
+	uptimeFile, err := os.Open("/proc/uptime")
+	if err != nil {
+		return UptimeInformation{}, fmt.Errorf("Could not find /proc/uptime. Are you sure you are on linux?")
+	}
+	defer uptimeFile.Close()
+
+	fileReader := bufio.NewScanner(uptimeFile)
+
+	var busyTime float64
+
+	fileReader.Scan()
+	if fileReader.Err() != nil {
+		return UptimeInformation{}, fmt.Errorf("Could not read /proc/uptime.")
+	}
+
+	data := fileReader.Text()
+
+	/*
+	 * fields[0] Time spent busy/suspended
+	 * fields[1] Time spent idling, it's combined from all CPU cores
+	 */
+	fields := strings.Split(data, " ")
+
+	busyTime, _ = strconv.ParseFloat(fields[0], 64)
+
+	return UptimeInformation{
+		uptime: busyTime,
+	}, nil
+}
+
+func GetUptimeInformation() (UptimeInformation, error) {
+	info, err := getLinuxUptime()
+	if err != nil {
+		return UptimeInformation{}, fmt.Errorf("Could not read uptime info. Error: %v", err)
+	}
+	return info, nil
+}