Move cgroups package into libcontainer

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/cgroups/fs/blkio.go

@@ -0,0 +1,121 @@
+package fs
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/dotcloud/docker/pkg/libcontainer/cgroups"
+)
+
+type blkioGroup struct {
+}
+
+func (s *blkioGroup) Set(d *data) error {
+	// we just want to join this group even though we don't set anything
+	if _, err := d.join("blkio"); err != nil && err != cgroups.ErrNotFound {
+		return err
+	}
+	return nil
+}
+
+func (s *blkioGroup) Remove(d *data) error {
+	return removePath(d.path("blkio"))
+}
+
+/*
+examples:
+
+    blkio.sectors
+    8:0 6792
+
+    blkio.io_service_bytes
+    8:0 Read 1282048
+    8:0 Write 2195456
+    8:0 Sync 2195456
+    8:0 Async 1282048
+    8:0 Total 3477504
+    Total 3477504
+
+    blkio.io_serviced
+    8:0 Read 124
+    8:0 Write 104
+    8:0 Sync 104
+    8:0 Async 124
+    8:0 Total 228
+    Total 228
+
+    blkio.io_queued
+    8:0 Read 0
+    8:0 Write 0
+    8:0 Sync 0
+    8:0 Async 0
+    8:0 Total 0
+    Total 0
+*/
+func (s *blkioGroup) Stats(d *data) (map[string]float64, error) {
+	var (
+		paramData = make(map[string]float64)
+		params    = []string{
+			"io_service_bytes_recursive",
+			"io_serviced_recursive",
+			"io_queued_recursive",
+		}
+	)
+
+	path, err := d.path("blkio")
+	if err != nil {
+		return nil, err
+	}
+
+	k, v, err := s.getSectors(path)
+	if err != nil {
+		return nil, err
+	}
+	paramData[fmt.Sprintf("blkio.sectors_recursive:%s", k)] = v
+
+	for _, param := range params {
+		f, err := os.Open(filepath.Join(path, fmt.Sprintf("blkio.%s", param)))
+		if err != nil {
+			return nil, err
+		}
+		defer f.Close()
+
+		sc := bufio.NewScanner(f)
+		for sc.Scan() {
+			// format: dev type amount
+			fields := strings.Fields(sc.Text())
+			switch len(fields) {
+			case 3:
+				v, err := strconv.ParseFloat(fields[2], 64)
+				if err != nil {
+					return nil, err
+				}
+				paramData[fmt.Sprintf("%s:%s:%s", param, fields[0], fields[1])] = v
+			case 2:
+				// this is the total line, skip
+			default:
+				return nil, ErrNotValidFormat
+			}
+		}
+	}
+	return paramData, nil
+}
+
+func (s *blkioGroup) getSectors(path string) (string, float64, error) {
+	f, err := os.Open(filepath.Join(path, "blkio.sectors_recursive"))
+	if err != nil {
+		return "", 0, err
+	}
+	defer f.Close()
+
+	data, err := ioutil.ReadAll(f)
+	if err != nil {
+		return "", 0, err
+	}
+	return getCgroupParamKeyValue(string(data))
+}