add memory stats

app/mem/drivers/meminfo.go

@@ -0,0 +1,63 @@
+package drivers
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type MemInfoDriver struct{}
+
+func NewMemInfoDriver() *MemInfoDriver {
+	return &MemInfoDriver{}
+}
+
+// Read /proc/meminfo for active system memory statistics
+func (r *MemInfoDriver) ReadUsageSensors() (MemoryUsage, error) {
+	usage := MemoryUsage{}
+	file, err := os.Open("/proc/meminfo")
+	if err != nil {
+		return usage, err
+	}
+	defer file.Close()
+
+	var memTotal, memAvailable float64
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+
+		val, err := strconv.ParseFloat(fields[1], 64)
+		if err != nil {
+			continue
+		}
+
+		switch fields[0] {
+		case "MemTotal:":
+			memTotal = val // stored in kB
+		case "MemAvailable:":
+			memAvailable = val // stored in kB
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		return usage, err
+	}
+
+	used := memTotal - memAvailable
+	usedPct := (used / memTotal) * 100
+
+	usage = MemoryUsage{
+		TotalGB:     memTotal / (1024 * 1024),
+		AvailableGB: memAvailable / (1024 * 1024),
+		UsedGB:      used / (1024 * 1024),
+		UsedPercent: usedPct,
+	}
+
+	return usage, nil
+}