dotcloud/docker

package meminfo

import (
    "bufio"
    "io"
    "os"
    "strconv"
    "strings"
)

// readMemInfo retrieves memory statistics of the host system and returns a
// Memory type.
func readMemInfo() (*Memory, error) {
    file, err := os.Open("/proc/meminfo")
    if err != nil {
        return nil, err
    }
    defer file.Close()
    return parseMemInfo(file)
}

// parseMemInfo parses the /proc/meminfo file into
// a Memory object given an io.Reader to the file.
// Throws error if there are problems reading from the file
func parseMemInfo(reader io.Reader) (*Memory, error) {
    meminfo := &Memory{}
    scanner := bufio.NewScanner(reader)
    memAvailable := int64(-1)
    for scanner.Scan() {
        // Expected format: ["MemTotal:", "1234", "kB"]
        parts := strings.Fields(scanner.Text())

        // Sanity checks: Skip malformed entries.
        if len(parts) < 3 || parts[2] != "kB" {
            continue
        }

        // Convert to bytes.
        size, err := strconv.Atoi(parts[1])
        if err != nil {
            continue
        }
        // Convert to KiB
        bytes := int64(size) * 1024

        switch parts[0] {
        case "MemTotal:":
            meminfo.MemTotal = bytes
        case "MemFree:":
            meminfo.MemFree = bytes
        case "MemAvailable:":
            memAvailable = bytes
        case "SwapTotal:":
            meminfo.SwapTotal = bytes
        case "SwapFree:":
            meminfo.SwapFree = bytes
        }
    }
    if memAvailable != -1 {
        meminfo.MemFree = memAvailable
    }

    // Handle errors that may have occurred during the reading of the file.
    if err := scanner.Err(); err != nil {
        return nil, err
    }

    return meminfo, nil
}