/
container_network_metrics_provider_linux.go
137 lines (113 loc) · 3.56 KB
/
container_network_metrics_provider_linux.go
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package gardener
import (
"bytes"
"flag"
"fmt"
"os"
"strconv"
"strings"
"code.cloudfoundry.org/garden"
"code.cloudfoundry.org/guardian/kawasaki/netns"
"code.cloudfoundry.org/lager/v3"
"github.com/docker/docker/pkg/reexec"
"github.com/vishvananda/netlink"
)
func init() {
reexec.Register("fetch-container-network-metrics", func() {
var netNsPath, ifName string
flag.StringVar(&netNsPath, "netNsPath", "", "netNsPath")
flag.StringVar(&ifName, "ifName", "", "ifName")
flag.Parse()
fd, err := os.Open(netNsPath)
if err != nil {
fmt.Fprintf(os.Stderr, "opening netns '%s': %s", netNsPath, err)
os.Exit(1)
}
defer fd.Close()
if err = (&netns.Execer{}).Exec(fd, func() error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("could not get link '%s', %w", ifName, err)
}
fmt.Print((&ContainerNetworkStatMarshaller{}).MarshalLink(link))
return nil
}); err != nil {
fmt.Fprint(os.Stderr, err.Error())
os.Exit(1)
}
})
}
type Opener func(path string) (*os.File, error)
func (o Opener) Open(path string) (*os.File, error) {
return o(path)
}
type ContainerNetworkStatMarshaller struct {
}
func (c *ContainerNetworkStatMarshaller) Unmarshal(s string) (*garden.ContainerNetworkStat, error) {
stats := strings.Split(s, ",")
if len(stats) != 2 {
return nil, fmt.Errorf("expected two values but got %q", s)
}
rxBytes, err := strconv.ParseUint(stats[0], 10, 64)
if err != nil {
return nil, fmt.Errorf("could not parse rx_bytes value %q, %w", stats[0], err)
}
txBytes, err := strconv.ParseUint(stats[1], 10, 64)
if err != nil {
return nil, fmt.Errorf("could not parse tx_bytes value %q, %w", stats[1], err)
}
return &garden.ContainerNetworkStat{
RxBytes: rxBytes,
TxBytes: txBytes,
}, nil
}
func (c *ContainerNetworkStatMarshaller) MarshalLink(link netlink.Link) string {
statistics := link.Attrs().Statistics
return fmt.Sprintf("%d,%d", statistics.RxBytes, statistics.TxBytes)
}
type LinuxContainerNetworkMetricsProvider struct {
containerizer Containerizer
propertyManager PropertyManager
fileOpener Opener
containerNetworkStatMarshaller *ContainerNetworkStatMarshaller
}
func NewLinuxContainerNetworkMetricsProvider(
containerizer Containerizer,
propertyManager PropertyManager,
fileOpener Opener,
) *LinuxContainerNetworkMetricsProvider {
return &LinuxContainerNetworkMetricsProvider{
containerizer: containerizer,
propertyManager: propertyManager,
fileOpener: fileOpener,
containerNetworkStatMarshaller: &ContainerNetworkStatMarshaller{},
}
}
func (l *LinuxContainerNetworkMetricsProvider) Get(log lager.Logger, handle string) (*garden.ContainerNetworkStat, error) {
log = log.Session("container-network-metrics")
ifName, found := l.propertyManager.Get(handle, ContainerInterfaceKey)
if !found || ifName == "" {
return nil, nil
}
info, err := l.containerizer.Info(log, handle)
if err != nil {
return nil, err
}
containerNetNs, err := l.fileOpener.Open(fmt.Sprintf("/proc/%d/ns/net", info.Pid))
if err != nil {
return nil, err
}
defer containerNetNs.Close()
stdout := new(bytes.Buffer)
stderr := new(bytes.Buffer)
cmd := reexec.Command("fetch-container-network-metrics",
"-ifName", ifName,
"-netNsPath", containerNetNs.Name(),
)
cmd.Stderr = stderr
cmd.Stdout = stdout
if err := cmd.Run(); err != nil {
return nil, fmt.Errorf("could not fetch container network metrics, %q, %w", stderr.String(), err)
}
return l.containerNetworkStatMarshaller.Unmarshal(stdout.String())
}