package execdriver
import (
"encoding/json"
"errors"
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"time"
"github.com/docker/docker/daemon/execdriver/native/template"
"github.com/docker/docker/pkg/ulimit"
"github.com/docker/libcontainer"
"github.com/docker/libcontainer/cgroups/fs"
"github.com/docker/libcontainer/configs"
)
// Context is a generic key value pair that allows
// arbatrary data to be sent
type Context map[string]string
var (
ErrNotRunning = errors.New("Container is not running")
ErrWaitTimeoutReached = errors.New("Wait timeout reached")
ErrDriverAlreadyRegistered = errors.New("A driver already registered this docker init function")
ErrDriverNotFound = errors.New("The requested docker init has not been found")
)
type StartCallback func(*ProcessConfig, int)
// Driver specific information based on
// processes registered with the driver
type Info interface {
IsRunning() bool
}
// Terminal in an interface for drivers to implement
// if they want to support Close and Resize calls from
// the core
type Terminal interface {
io.Closer
Resize(height, width int) error
}
type TtyTerminal interface {
Master() libcontainer.Console
}
// ExitStatus provides exit reasons for a container.
type ExitStatus struct {
// The exit code with which the container exited.
ExitCode int
// Whether the container encountered an OOM.
OOMKilled bool
}
type Driver interface {
Run(c *Command, pipes *Pipes, startCallback StartCallback) (ExitStatus, error) // Run executes the process and blocks until the process exits and returns the exit code
// Exec executes the process in an existing container, blocks until the process exits and returns the exit code
Exec(c *Command, processConfig *ProcessConfig, pipes *Pipes, startCallback StartCallback) (int, error)
Kill(c *Command, sig int) error
Pause(c *Command) error
Unpause(c *Command) error
Name() string // Driver name
Info(id string) Info // "temporary" hack (until we move state from core to plugins)
GetPidsForContainer(id string) ([]int, error) // Returns a list of pids for the given container.
Terminate(c *Command) error // kill it with fire
Clean(id string) error // clean all traces of container exec
Stats(id string) (*ResourceStats, error) // Get resource stats for a running container
}
// Network settings of the container
type Network struct {
Interface *NetworkInterface `json:"interface"` // if interface is nil then networking is disabled
Mtu int `json:"mtu"`
ContainerID string `json:"container_id"` // id of the container to join network.
HostNetworking bool `json:"host_networking"`
}
// IPC settings of the container
type Ipc struct {
ContainerID string `json:"container_id"` // id of the container to join ipc.
HostIpc bool `json:"host_ipc"`
}
// PID settings of the container
type Pid struct {
HostPid bool `json:"host_pid"`
}
type NetworkInterface struct {
Gateway string `json:"gateway"`
IPAddress string `json:"ip"`
IPPrefixLen int `json:"ip_prefix_len"`
MacAddress string `json:"mac"`
Bridge string `json:"bridge"`
GlobalIPv6Address string `json:"global_ipv6"`
LinkLocalIPv6Address string `json:"link_local_ipv6"`
GlobalIPv6PrefixLen int `json:"global_ipv6_prefix_len"`
IPv6Gateway string `json:"ipv6_gateway"`
}
type Resources struct {
Memory int64 `json:"memory"`
MemorySwap int64 `json:"memory_swap"`
CpuShares int64 `json:"cpu_shares"`
CpusetCpus string `json:"cpuset_cpus"`
Rlimits []*ulimit.Rlimit `json:"rlimits"`
}
type ResourceStats struct {
*libcontainer.Stats
Read time.Time `json:"read"`
MemoryLimit int64 `json:"memory_limit"`
SystemUsage uint64 `json:"system_usage"`
}
type Mount struct {
Source string `json:"source"`
Destination string `json:"destination"`
Writable bool `json:"writable"`
Private bool `json:"private"`
Slave bool `json:"slave"`
}
// Describes a process that will be run inside a container.
type ProcessConfig struct {
exec.Cmd `json:"-"`
Privileged bool `json:"privileged"`
User string `json:"user"`
Tty bool `json:"tty"`
Entrypoint string `json:"entrypoint"`
Arguments []string `json:"arguments"`
Terminal Terminal `json:"-"` // standard or tty terminal
Console string `json:"-"` // dev/console path
}
// Process wrapps an os/exec.Cmd to add more metadata
type Command struct {
ID string `json:"id"`
Rootfs string `json:"rootfs"` // root fs of the container
ReadonlyRootfs bool `json:"readonly_rootfs"`
InitPath string `json:"initpath"` // dockerinit
WorkingDir string `json:"working_dir"`
ConfigPath string `json:"config_path"` // this should be able to be removed when the lxc template is moved into the driver
Network *Network `json:"network"`
Ipc *Ipc `json:"ipc"`
Pid *Pid `json:"pid"`
Resources *Resources `json:"resources"`
Mounts []Mount `json:"mounts"`
AllowedDevices []*configs.Device `json:"allowed_devices"`
AutoCreatedDevices []*configs.Device `json:"autocreated_devices"`
CapAdd []string `json:"cap_add"`
CapDrop []string `json:"cap_drop"`
ContainerPid int `json:"container_pid"` // the pid for the process inside a container
ProcessConfig ProcessConfig `json:"process_config"` // Describes the init process of the container.
ProcessLabel string `json:"process_label"`
MountLabel string `json:"mount_label"`
LxcConfig []string `json:"lxc_config"`
AppArmorProfile string `json:"apparmor_profile"`
CgroupParent string `json:"cgroup_parent"` // The parent cgroup for this command.
}
func InitContainer(c *Command) *configs.Config {
container := template.New()
container.Hostname = getEnv("HOSTNAME", c.ProcessConfig.Env)
container.Cgroups.Name = c.ID
container.Cgroups.AllowedDevices = c.AllowedDevices
container.Devices = c.AutoCreatedDevices
container.Rootfs = c.Rootfs
container.Readonlyfs = c.ReadonlyRootfs
// check to see if we are running in ramdisk to disable pivot root
container.NoPivotRoot = os.Getenv("DOCKER_RAMDISK") != ""
// Default parent cgroup is "docker". Override if required.
if c.CgroupParent != "" {
container.Cgroups.Parent = c.CgroupParent
}
return container
}
func getEnv(key string, env []string) string {
for _, pair := range env {
parts := strings.Split(pair, "=")
if parts[0] == key {
return parts[1]
}
}
return ""
}
func SetupCgroups(container *configs.Config, c *Command) error {
if c.Resources != nil {
container.Cgroups.CpuShares = c.Resources.CpuShares
container.Cgroups.Memory = c.Resources.Memory
container.Cgroups.MemoryReservation = c.Resources.Memory
container.Cgroups.MemorySwap = c.Resources.MemorySwap
container.Cgroups.CpusetCpus = c.Resources.CpusetCpus
}
return nil
}
// Returns the network statistics for the network interfaces represented by the NetworkRuntimeInfo.
func getNetworkInterfaceStats(interfaceName string) (*libcontainer.NetworkInterface, error) {
out := &libcontainer.NetworkInterface{Name: interfaceName}
// This can happen if the network runtime information is missing - possible if the
// container was created by an old version of libcontainer.
if interfaceName == "" {
return out, nil
}
type netStatsPair struct {
// Where to write the output.
Out *uint64
// The network stats file to read.
File string
}
// Ingress for host veth is from the container. Hence tx_bytes stat on the host veth is actually number of bytes received by the container.
netStats := []netStatsPair{
{Out: &out.RxBytes, File: "tx_bytes"},
{Out: &out.RxPackets, File: "tx_packets"},
{Out: &out.RxErrors, File: "tx_errors"},
{Out: &out.RxDropped, File: "tx_dropped"},
{Out: &out.TxBytes, File: "rx_bytes"},
{Out: &out.TxPackets, File: "rx_packets"},
{Out: &out.TxErrors, File: "rx_errors"},
{Out: &out.TxDropped, File: "rx_dropped"},
}
for _, netStat := range netStats {
data, err := readSysfsNetworkStats(interfaceName, netStat.File)
if err != nil {
return nil, err
}
*(netStat.Out) = data
}
return out, nil
}
// Reads the specified statistics available under /sys/class/net/<EthInterface>/statistics
func readSysfsNetworkStats(ethInterface, statsFile string) (uint64, error) {
data, err := ioutil.ReadFile(filepath.Join("/sys/class/net", ethInterface, "statistics", statsFile))
if err != nil {
return 0, err
}
return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
}
func Stats(containerDir string, containerMemoryLimit int64, machineMemory int64) (*ResourceStats, error) {
f, err := os.Open(filepath.Join(containerDir, "state.json"))
if err != nil {
return nil, err
}
defer f.Close()
type network struct {
Type string
HostInterfaceName string
}
state := struct {
CgroupPaths map[string]string `json:"cgroup_paths"`
Networks []network
}{}
if err := json.NewDecoder(f).Decode(&state); err != nil {
return nil, err
}
now := time.Now()
mgr := fs.Manager{Paths: state.CgroupPaths}
cstats, err := mgr.GetStats()
if err != nil {
return nil, err
}
stats := &libcontainer.Stats{CgroupStats: cstats}
// if the container does not have any memory limit specified set the
// limit to the machines memory
memoryLimit := containerMemoryLimit
if memoryLimit == 0 {
memoryLimit = machineMemory
}
for _, iface := range state.Networks {
switch iface.Type {
case "veth":
istats, err := getNetworkInterfaceStats(iface.HostInterfaceName)
if err != nil {
return nil, err
}
stats.Interfaces = append(stats.Interfaces, istats)
}
}
return &ResourceStats{
Stats: stats,
Read: now,
MemoryLimit: memoryLimit,
}, nil
}