1package system
2
3import (
4	"bufio"
5	"io"
6	"os"
7	"strconv"
8	"strings"
9
10	"github.com/docker/go-units"
11)
12
13// ReadMemInfo retrieves memory statistics of the host system and returns a
14// MemInfo type.
15func ReadMemInfo() (*MemInfo, error) {
16	file, err := os.Open("/proc/meminfo")
17	if err != nil {
18		return nil, err
19	}
20	defer file.Close()
21	return parseMemInfo(file)
22}
23
24// parseMemInfo parses the /proc/meminfo file into
25// a MemInfo object given an io.Reader to the file.
26// Throws error if there are problems reading from the file
27func parseMemInfo(reader io.Reader) (*MemInfo, error) {
28	meminfo := &MemInfo{}
29	scanner := bufio.NewScanner(reader)
30	for scanner.Scan() {
31		// Expected format: ["MemTotal:", "1234", "kB"]
32		parts := strings.Fields(scanner.Text())
33
34		// Sanity checks: Skip malformed entries.
35		if len(parts) < 3 || parts[2] != "kB" {
36			continue
37		}
38
39		// Convert to bytes.
40		size, err := strconv.Atoi(parts[1])
41		if err != nil {
42			continue
43		}
44		bytes := int64(size) * units.KiB
45
46		switch parts[0] {
47		case "MemTotal:":
48			meminfo.MemTotal = bytes
49		case "MemFree:":
50			meminfo.MemFree = bytes
51		case "SwapTotal:":
52			meminfo.SwapTotal = bytes
53		case "SwapFree:":
54			meminfo.SwapFree = bytes
55		}
56
57	}
58
59	// Handle errors that may have occurred during the reading of the file.
60	if err := scanner.Err(); err != nil {
61		return nil, err
62	}
63
64	return meminfo, nil
65}
66