Fix golint warnings for daemon/execdriver/*

Addresses: #14756

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

daemon/container_unix.go

@@ -272,11 +272,11 @@ func populateCommand(c *Container, env []string) error {
 	resources := &execdriver.Resources{
 		Memory:           c.hostConfig.Memory,
 		MemorySwap:       c.hostConfig.MemorySwap,
-		CpuShares:        c.hostConfig.CPUShares,
+		CPUShares:        c.hostConfig.CPUShares,
 		CpusetCpus:       c.hostConfig.CpusetCpus,
 		CpusetMems:       c.hostConfig.CpusetMems,
-		CpuPeriod:        c.hostConfig.CPUPeriod,
+		CPUPeriod:        c.hostConfig.CPUPeriod,
-		CpuQuota:         c.hostConfig.CPUQuota,
+		CPUQuota:         c.hostConfig.CPUQuota,
 		BlkioWeight:      c.hostConfig.BlkioWeight,
 		Rlimits:          rlimits,
 		OomKillDisable:   c.hostConfig.OomKillDisable,

daemon/execdriver/driver.go

@@ -16,6 +16,7 @@ import (
 // arbatrary data to be sent
 type Context map[string]string
 
+// Define error messages
 var (
 	ErrNotRunning              = errors.New("Container is not running")
 	ErrWaitTimeoutReached      = errors.New("Wait timeout reached")
@@ -23,17 +24,19 @@ var (
 	ErrDriverNotFound          = errors.New("The requested docker init has not been found")
 )
 
+// StartCallback defines a callback function.
+// It's used by 'Run' and 'Exec', does some work in parent process
+// after child process is started.
 type StartCallback func(*ProcessConfig, int)
 
-// Driver specific information based on
+// Info is driver specific information based on
 // processes registered with the driver
 type Info interface {
 	IsRunning() bool
 }
 
-// Terminal in an interface for drivers to implement
+// Terminal represents a pseudo TTY, it is for when
-// if they want to support Close and Resize calls from
+// using a container interactively.
-// the core
 type Terminal interface {
 	io.Closer
 	Resize(height, width int) error
@@ -48,19 +51,44 @@ type ExitStatus struct {
 	OOMKilled bool
 }
 
+// Driver is an interface for drivers to implement
+// including all basic functions a driver should have
 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
+	// Run executes the process, blocks until the process exits and returns
-	// Exec executes the process in an existing container, blocks until the process exits and returns the exit code
+	// the exit code. It's the last stage on Docker side for running a container.
+	Run(c *Command, pipes *Pipes, startCallback StartCallback) (ExitStatus, error)
+
+	// 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 sends signals to process in container.
 	Kill(c *Command, sig int) error
+
+	// Pause pauses a container.
 	Pause(c *Command) error
+
+	// Unpause unpauses a container.
 	Unpause(c *Command) error
-	Name() string                                 // Driver name
+
-	Info(id string) Info                          // "temporary" hack (until we move state from core to plugins)
+	// Name returns the name of the driver.
-	GetPidsForContainer(id string) ([]int, error) // Returns a list of pids for the given container.
+	Name() string
-	Terminate(c *Command) error                   // kill it with fire
+
-	Clean(id string) error                        // clean all traces of container exec
+	// Info returns the configuration stored in the driver struct,
-	Stats(id string) (*ResourceStats, error)      // Get resource stats for a running container
+	// "temporary" hack (until we move state from core to plugins).
+	Info(id string) Info
+
+	// GetPidsForContainer returns a list of pid for the processes running in a container.
+	GetPidsForContainer(id string) ([]int, error)
+
+	// Terminate kills a container by sending signal SIGKILL.
+	Terminate(c *Command) error
+
+	// Clean removes all traces of container exec.
+	Clean(id string) error
+
+	// Stats returns resource stats for a running container
+	Stats(id string) (*ResourceStats, error)
 }
 
 // Network settings of the container
@@ -72,22 +100,37 @@ type Network struct {
 	HostNetworking bool              `json:"host_networking"`
 }
 
-// IPC settings of the container
+// Ipc settings of the container
+// It is for IPC namespace setting. Usually different containers
+// have their own IPC namespace, however this specifies to use
+// an existing IPC namespace.
+// You can join the host's or a container's IPC namespace.
 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
+// Pid settings of the container
+// It is for PID namespace setting. Usually different containers
+// have their own PID namespace, however this specifies to use
+// an existing PID namespace.
+// Joining the host's PID namespace is currently the only supported
+// option.
 type Pid struct {
 	HostPid bool `json:"host_pid"`
 }
 
 // UTS settings of the container
+// It is for UTS namespace setting. Usually different containers
+// have their own UTS namespace, however this specifies to use
+// an existing UTS namespace.
+// Joining the host's UTS namespace is currently the only supported
+// option.
 type UTS struct {
 	HostUTS bool `json:"host_uts"`
 }
 
+// NetworkInterface contains all network configs for a driver
 type NetworkInterface struct {
 	Gateway              string `json:"gateway"`
 	IPAddress            string `json:"ip"`
@@ -101,21 +144,24 @@ type NetworkInterface struct {
 	HairpinMode          bool   `json:"hairpin_mode"`
 }
 
+// Resources contains all resource configs for a driver.
+// Currently these are all for cgroup configs.
 // TODO Windows: Factor out ulimit.Rlimit
 type Resources struct {
 	Memory           int64            `json:"memory"`
 	MemorySwap       int64            `json:"memory_swap"`
-	CpuShares        int64            `json:"cpu_shares"`
+	CPUShares        int64            `json:"cpu_shares"`
 	CpusetCpus       string           `json:"cpuset_cpus"`
 	CpusetMems       string           `json:"cpuset_mems"`
-	CpuPeriod        int64            `json:"cpu_period"`
+	CPUPeriod        int64            `json:"cpu_period"`
-	CpuQuota         int64            `json:"cpu_quota"`
+	CPUQuota         int64            `json:"cpu_quota"`
 	BlkioWeight      int64            `json:"blkio_weight"`
 	Rlimits          []*ulimit.Rlimit `json:"rlimits"`
 	OomKillDisable   bool             `json:"oom_kill_disable"`
 	MemorySwappiness int64            `json:"memory_swappiness"`
 }
 
+// ResourceStats contains information about resource usage by a container.
 type ResourceStats struct {
 	*libcontainer.Stats
 	Read        time.Time `json:"read"`
@@ -123,6 +169,7 @@ type ResourceStats struct {
 	SystemUsage uint64    `json:"system_usage"`
 }
 
+// Mount contains information for a mount operation.
 type Mount struct {
 	Source      string `json:"source"`
 	Destination string `json:"destination"`
@@ -131,7 +178,7 @@ type Mount struct {
 	Slave       bool   `json:"slave"`
 }
 
-// Describes a process that will be run inside a container.
+// ProcessConfig describes a process that will be run inside a container.
 type ProcessConfig struct {
 	exec.Cmd `json:"-"`
 
@@ -145,10 +192,10 @@ type ProcessConfig struct {
 	ConsoleSize [2]int   `json:"-"` // h,w of initial console size
 }
 
+// Command wrapps an os/exec.Cmd to add more metadata
+//
 // TODO Windows: Factor out unused fields such as LxcConfig, AppArmorProfile,
 // and CgroupParent.
-//
-// 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

daemon/execdriver/driver_linux.go

@@ -15,6 +15,9 @@ import (
 	"github.com/opencontainers/runc/libcontainer/configs"
 )
 
+// InitContainer is the initialization of a container config.
+// It returns the initial configs for a container. It's mostly
+// defined by the default template.
 func InitContainer(c *Command) *configs.Config {
 	container := template.New()
 
@@ -46,16 +49,17 @@ func getEnv(key string, env []string) string {
 	return ""
 }
 
+// SetupCgroups setups cgroup resources for a container.
 func SetupCgroups(container *configs.Config, c *Command) error {
 	if c.Resources != nil {
-		container.Cgroups.CpuShares = c.Resources.CpuShares
+		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
 		container.Cgroups.CpusetMems = c.Resources.CpusetMems
-		container.Cgroups.CpuPeriod = c.Resources.CpuPeriod
+		container.Cgroups.CpuPeriod = c.Resources.CPUPeriod
-		container.Cgroups.CpuQuota = c.Resources.CpuQuota
+		container.Cgroups.CpuQuota = c.Resources.CPUQuota
 		container.Cgroups.BlkioWeight = c.Resources.BlkioWeight
 		container.Cgroups.OomKillDisable = c.Resources.OomKillDisable
 		container.Cgroups.MemorySwappiness = c.Resources.MemorySwappiness
@@ -109,6 +113,7 @@ func readSysfsNetworkStats(ethInterface, statsFile string) (uint64, error) {
 	return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
 }
 
+// Stats collects all the resource usage information from a container.
 func Stats(containerDir string, containerMemoryLimit int64, machineMemory int64) (*ResourceStats, error) {
 	f, err := os.Open(filepath.Join(containerDir, "state.json"))
 	if err != nil {

daemon/execdriver/execdrivers/execdrivers_linux.go

@@ -12,6 +12,7 @@ import (
 	"github.com/docker/docker/pkg/sysinfo"
 )
 
+// NewDriver returns a new execdriver.Driver from the given name configured with the provided options.
 func NewDriver(name string, options []string, root, libPath, initPath string, sysInfo *sysinfo.SysInfo) (execdriver.Driver, error) {
 	switch name {
 	case "lxc":

daemon/execdriver/execdrivers/execdrivers_windows.go

@@ -10,6 +10,7 @@ import (
 	"github.com/docker/docker/pkg/sysinfo"
 )
 
+// NewDriver returns a new execdriver.Driver from the given name configured with the provided options.
 func NewDriver(name string, options []string, root, libPath, initPath string, sysInfo *sysinfo.SysInfo) (execdriver.Driver, error) {
 	switch name {
 	case "windows":

daemon/execdriver/lxc/driver.go

@@ -34,11 +34,15 @@ import (
 	"github.com/vishvananda/netns"
 )
 
+// DriverName for lxc driver
 const DriverName = "lxc"
 
+// ErrExec defines unsupported error message
 var ErrExec = errors.New("Unsupported: Exec is not supported by the lxc driver")
 
-type driver struct {
+// Driver contains all information for lxc driver,
+// it implements execdriver.Driver
+type Driver struct {
 	root             string // root path for the driver to use
 	libPath          string
 	initPath         string
@@ -54,7 +58,8 @@ type activeContainer struct {
 	cmd       *exec.Cmd
 }
 
-func NewDriver(root, libPath, initPath string, apparmor bool) (*driver, error) {
+// NewDriver returns a new lxc driver, called from NewDriver of execdriver
+func NewDriver(root, libPath, initPath string, apparmor bool) (*Driver, error) {
 	if err := os.MkdirAll(root, 0700); err != nil {
 		return nil, err
 	}
@@ -66,7 +71,7 @@ func NewDriver(root, libPath, initPath string, apparmor bool) (*driver, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &driver{
+	return &Driver{
 		apparmor:         apparmor,
 		root:             root,
 		libPath:          libPath,
@@ -77,7 +82,8 @@ func NewDriver(root, libPath, initPath string, apparmor bool) (*driver, error) {
 	}, nil
 }
 
-func (d *driver) Name() string {
+// Name implements the exec driver Driver interface.
+func (d *Driver) Name() string {
 	version := d.version()
 	return fmt.Sprintf("%s-%s", DriverName, version)
 }
@@ -117,7 +123,9 @@ func killNetNsProc(proc *os.Process) {
 	proc.Wait()
 }
 
-func (d *driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (execdriver.ExitStatus, error) {
+// Run implements the exec driver Driver interface,
+// it calls 'exec.Cmd' to launch lxc commands to run a container.
+func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (execdriver.ExitStatus, error) {
 	var (
 		term     execdriver.Terminal
 		err      error
@@ -392,7 +400,7 @@ func notifyOnOOM(paths map[string]string) (<-chan struct{}, error) {
 
 // createContainer populates and configures the container type with the
 // data provided by the execdriver.Command
-func (d *driver) createContainer(c *execdriver.Command) (*configs.Config, error) {
+func (d *Driver) createContainer(c *execdriver.Command) (*configs.Config, error) {
 	container := execdriver.InitContainer(c)
 	if err := execdriver.SetupCgroups(container, c); err != nil {
 		return nil, err
@@ -400,8 +408,8 @@ func (d *driver) createContainer(c *execdriver.Command) (*configs.Config, error)
 	return container, nil
 }
 
-// Return an map of susbystem -> container cgroup
+// Return an map of susbystem -> absolute container cgroup path
-func cgroupPaths(containerId string) (map[string]string, error) {
+func cgroupPaths(containerID string) (map[string]string, error) {
 	subsystems, err := cgroups.GetAllSubsystems()
 	if err != nil {
 		return nil, err
@@ -415,7 +423,7 @@ func cgroupPaths(containerId string) (map[string]string, error) {
 			//unsupported subystem
 			continue
 		}
-		path := filepath.Join(cgroupRoot, cgroupDir, "lxc", containerId)
+		path := filepath.Join(cgroupRoot, cgroupDir, "lxc", containerID)
 		paths[subsystem] = path
 	}
 
@@ -506,8 +514,8 @@ func setupUser(userSpec string) error {
 	return nil
 }
 
-/// Return the exit code of the process
+// getExitCode returns the exit code of the process.
-// if the process has not exited -1 will be returned
+// If the process has not exited -1 will be returned.
 func getExitCode(c *execdriver.Command) int {
 	if c.ProcessConfig.ProcessState == nil {
 		return -1
@@ -515,15 +523,18 @@ func getExitCode(c *execdriver.Command) int {
 	return c.ProcessConfig.ProcessState.Sys().(syscall.WaitStatus).ExitStatus()
 }
 
-func (d *driver) Kill(c *execdriver.Command, sig int) error {
+// Kill implements the exec driver Driver interface.
+func (d *Driver) Kill(c *execdriver.Command, sig int) error {
 	if sig == 9 || c.ProcessConfig.Process == nil {
-		return KillLxc(c.ID, sig)
+		return killLxc(c.ID, sig)
 	}
 
 	return c.ProcessConfig.Process.Signal(syscall.Signal(sig))
 }
 
-func (d *driver) Pause(c *execdriver.Command) error {
+// Pause implements the exec driver Driver interface,
+// it executes lxc-freeze to pause a container.
+func (d *Driver) Pause(c *execdriver.Command) error {
 	_, err := exec.LookPath("lxc-freeze")
 	if err == nil {
 		output, errExec := exec.Command("lxc-freeze", "-n", c.ID).CombinedOutput()
@@ -535,7 +546,9 @@ func (d *driver) Pause(c *execdriver.Command) error {
 	return err
 }
 
-func (d *driver) Unpause(c *execdriver.Command) error {
+// Unpause implements the exec driver Driver interface,
+// it executes lxc-unfreeze to unpause a container.
+func (d *Driver) Unpause(c *execdriver.Command) error {
 	_, err := exec.LookPath("lxc-unfreeze")
 	if err == nil {
 		output, errExec := exec.Command("lxc-unfreeze", "-n", c.ID).CombinedOutput()
@@ -547,11 +560,12 @@ func (d *driver) Unpause(c *execdriver.Command) error {
 	return err
 }
 
-func (d *driver) Terminate(c *execdriver.Command) error {
+// Terminate implements the exec driver Driver interface.
-	return KillLxc(c.ID, 9)
+func (d *Driver) Terminate(c *execdriver.Command) error {
+	return killLxc(c.ID, 9)
 }
 
-func (d *driver) version() string {
+func (d *Driver) version() string {
 	var (
 		version string
 		output  []byte
@@ -571,7 +585,7 @@ func (d *driver) version() string {
 	return version
 }
 
-func KillLxc(id string, sig int) error {
+func killLxc(id string, sig int) error {
 	var (
 		err    error
 		output []byte
@@ -590,7 +604,7 @@ func KillLxc(id string, sig int) error {
 }
 
 // wait for the process to start and return the pid for the process
-func (d *driver) waitForStart(c *execdriver.Command, waitLock chan struct{}) (int, error) {
+func (d *Driver) waitForStart(c *execdriver.Command, waitLock chan struct{}) (int, error) {
 	var (
 		err    error
 		output []byte
@@ -622,13 +636,13 @@ func (d *driver) waitForStart(c *execdriver.Command, waitLock chan struct{}) (in
 	return -1, execdriver.ErrNotRunning
 }
 
-func (d *driver) getInfo(id string) ([]byte, error) {
+func (d *Driver) getInfo(id string) ([]byte, error) {
 	return exec.Command("lxc-info", "-n", id).CombinedOutput()
 }
 
 type info struct {
 	ID     string
-	driver *driver
+	driver *Driver
 }
 
 func (i *info) IsRunning() bool {
@@ -645,7 +659,8 @@ func (i *info) IsRunning() bool {
 	return running
 }
 
-func (d *driver) Info(id string) execdriver.Info {
+// Info implements the exec driver Driver interface.
+func (d *Driver) Info(id string) execdriver.Info {
 	return &info{
 		ID:     id,
 		driver: d,
@@ -665,7 +680,8 @@ func findCgroupRootAndDir(subsystem string) (string, string, error) {
 	return cgroupRoot, cgroupDir, nil
 }
 
-func (d *driver) GetPidsForContainer(id string) ([]int, error) {
+// GetPidsForContainer implements the exec driver Driver interface.
+func (d *Driver) GetPidsForContainer(id string) ([]int, error) {
 	pids := []int{}
 
 	// cpu is chosen because it is the only non optional subsystem in cgroups
@@ -730,11 +746,11 @@ func rootIsShared() bool {
 	return true
 }
 
-func (d *driver) containerDir(containerId string) string {
+func (d *Driver) containerDir(containerID string) string {
-	return path.Join(d.libPath, "containers", containerId)
+	return path.Join(d.libPath, "containers", containerID)
 }
 
-func (d *driver) generateLXCConfig(c *execdriver.Command) (string, error) {
+func (d *Driver) generateLXCConfig(c *execdriver.Command) (string, error) {
 	root := path.Join(d.containerDir(c.ID), "config.lxc")
 
 	fo, err := os.Create(root)
@@ -743,7 +759,7 @@ func (d *driver) generateLXCConfig(c *execdriver.Command) (string, error) {
 	}
 	defer fo.Close()
 
-	if err := LxcTemplateCompiled.Execute(fo, struct {
+	if err := lxcTemplateCompiled.Execute(fo, struct {
 		*execdriver.Command
 		AppArmor bool
 	}{
@@ -756,7 +772,7 @@ func (d *driver) generateLXCConfig(c *execdriver.Command) (string, error) {
 	return root, nil
 }
 
-func (d *driver) generateEnvConfig(c *execdriver.Command) error {
+func (d *Driver) generateEnvConfig(c *execdriver.Command) error {
 	data, err := json.Marshal(c.ProcessConfig.Env)
 	if err != nil {
 		return err
@@ -772,16 +788,21 @@ func (d *driver) generateEnvConfig(c *execdriver.Command) error {
 	return ioutil.WriteFile(p, data, 0600)
 }
 
-// Clean not implemented for lxc
+// Clean implements the exec driver Driver interface,
-func (d *driver) Clean(id string) error {
+// it's not implemented by lxc.
+func (d *Driver) Clean(id string) error {
 	return nil
 }
 
+// TtyConsole implements the exec driver Terminal interface,
+// it stores the master and slave ends of the container's pty.
 type TtyConsole struct {
 	MasterPty *os.File
 	SlavePty  *os.File
 }
 
+// NewTtyConsole returns a new TtyConsole struct.
+// Wired up to the provided process config and stdin/stdout/stderr pipes.
 func NewTtyConsole(processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes) (*TtyConsole, error) {
 	// lxc is special in that we cannot create the master outside of the container without
 	// opening the slave because we have nothing to provide to the cmd.  We have to open both then do
@@ -808,10 +829,12 @@ func NewTtyConsole(processConfig *execdriver.ProcessConfig, pipes *execdriver.Pi
 	return tty, nil
 }
 
+// Resize implements Resize method of Terminal interface
 func (t *TtyConsole) Resize(h, w int) error {
 	return term.SetWinsize(t.MasterPty.Fd(), &term.Winsize{Height: uint16(h), Width: uint16(w)})
 }
 
+// AttachPipes attaches given pipes to exec.Cmd
 func (t *TtyConsole) AttachPipes(command *exec.Cmd, pipes *execdriver.Pipes) error {
 	command.Stdout = t.SlavePty
 	command.Stderr = t.SlavePty
@@ -839,16 +862,22 @@ func (t *TtyConsole) AttachPipes(command *exec.Cmd, pipes *execdriver.Pipes) err
 	return nil
 }
 
+// Close implements Close method of Terminal interface
 func (t *TtyConsole) Close() error {
 	t.SlavePty.Close()
 	return t.MasterPty.Close()
 }
 
-func (d *driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
+// Exec implements the exec driver Driver interface,
+// it is not implemented by lxc.
+func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
 	return -1, ErrExec
 }
 
-func (d *driver) Stats(id string) (*execdriver.ResourceStats, error) {
+// Stats implements the exec driver Driver interface.
+// Lxc doesn't implement it's own Stats, it does some trick by implementing
+// execdriver.Stats to get stats info by libcontainer APIs.
+func (d *Driver) Stats(id string) (*execdriver.ResourceStats, error) {
 	if _, ok := d.activeContainers[id]; !ok {
 		return nil, fmt.Errorf("%s is not a key in active containers", id)
 	}

daemon/execdriver/lxc/info.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 )
 
+// Define error messages
 var (
 	ErrCannotParse = errors.New("cannot parse raw input")
 )

daemon/execdriver/lxc/init.go

@@ -16,11 +16,11 @@ import (
 	"github.com/docker/docker/pkg/reexec"
 )
 
-// Args provided to the init function for a driver
+// InitArgs contains args provided to the init function for a driver
 type InitArgs struct {
 	User       string
 	Gateway    string
-	Ip         string
+	IP         string
 	WorkDir    string
 	Privileged bool
 	Env        []string
@@ -94,7 +94,7 @@ func getArgs() *InitArgs {
 	return &InitArgs{
 		User:       *user,
 		Gateway:    *gateway,
-		Ip:         *ip,
+		IP:         *ip,
 		WorkDir:    *workDir,
 		Privileged: *privileged,
 		Args:       flag.Args(),

daemon/execdriver/lxc/lxc_template.go

@@ -15,6 +15,8 @@ import (
 	"github.com/opencontainers/runc/libcontainer/label"
 )
 
+// LxcTemplate is the template for lxc driver, it's used
+// to configure LXC.
 const LxcTemplate = `
 lxc.network.type = none
 # root filesystem
@@ -94,11 +96,11 @@ lxc.cgroup.memory.soft_limit_in_bytes = {{.Resources.Memory}}
 lxc.cgroup.memory.memsw.limit_in_bytes = {{$memSwap}}
 {{end}}
 {{end}}
-{{if .Resources.CpuShares}}
+{{if .Resources.CPUShares}}
-lxc.cgroup.cpu.shares = {{.Resources.CpuShares}}
+lxc.cgroup.cpu.shares = {{.Resources.CPUShares}}
 {{end}}
-{{if .Resources.CpuPeriod}}
+{{if .Resources.CPUPeriod}}
-lxc.cgroup.cpu.cfs_period_us = {{.Resources.CpuPeriod}}
+lxc.cgroup.cpu.cfs_period_us = {{.Resources.CPUPeriod}}
 {{end}}
 {{if .Resources.CpusetCpus}}
 lxc.cgroup.cpuset.cpus = {{.Resources.CpusetCpus}}
@@ -106,8 +108,8 @@ lxc.cgroup.cpuset.cpus = {{.Resources.CpusetCpus}}
 {{if .Resources.CpusetMems}}
 lxc.cgroup.cpuset.mems = {{.Resources.CpusetMems}}
 {{end}}
-{{if .Resources.CpuQuota}}
+{{if .Resources.CPUQuota}}
-lxc.cgroup.cpu.cfs_quota_us = {{.Resources.CpuQuota}}
+lxc.cgroup.cpu.cfs_quota_us = {{.Resources.CPUQuota}}
 {{end}}
 {{if .Resources.BlkioWeight}}
 lxc.cgroup.blkio.weight = {{.Resources.BlkioWeight}}
@@ -158,7 +160,7 @@ lxc.cap.drop = {{.}}
 {{end}}
 `
 
-var LxcTemplateCompiled *template.Template
+var lxcTemplateCompiled *template.Template
 
 // Escape spaces in strings according to the fstab documentation, which is the
 // format for "lxc.mount.entry" lines in lxc.conf. See also "man 5 fstab".
@@ -254,7 +256,7 @@ func init() {
 		"dropList":          dropList,
 		"getHostname":       getHostname,
 	}
-	LxcTemplateCompiled, err = template.New("lxc").Funcs(funcMap).Parse(LxcTemplate)
+	lxcTemplateCompiled, err = template.New("lxc").Funcs(funcMap).Parse(LxcTemplate)
 	if err != nil {
 		panic(err)
 	}

daemon/execdriver/lxc/lxc_template_unit_test.go

@@ -47,7 +47,7 @@ func TestLXCConfig(t *testing.T) {
 		ID: "1",
 		Resources: &execdriver.Resources{
 			Memory:    int64(mem),
-			CpuShares: int64(cpu),
+			CPUShares: int64(cpu),
 		},
 		Network: &execdriver.Network{
 			Mtu:       1500,

daemon/execdriver/native/create.go

@@ -18,7 +18,7 @@ import (
 
 // createContainer populates and configures the container type with the
 // data provided by the execdriver.Command
-func (d *driver) createContainer(c *execdriver.Command) (*configs.Config, error) {
+func (d *Driver) createContainer(c *execdriver.Command) (*configs.Config, error) {
 	container := execdriver.InitContainer(c)
 
 	if err := d.createIpc(container, c); err != nil {
@@ -113,7 +113,7 @@ func generateIfaceName() (string, error) {
 	return "", errors.New("Failed to find name for new interface")
 }
 
-func (d *driver) createNetwork(container *configs.Config, c *execdriver.Command) error {
+func (d *Driver) createNetwork(container *configs.Config, c *execdriver.Command) error {
 	if c.Network == nil {
 		return nil
 	}
@@ -143,7 +143,7 @@ func (d *driver) createNetwork(container *configs.Config, c *execdriver.Command)
 	return nil
 }
 
-func (d *driver) createIpc(container *configs.Config, c *execdriver.Command) error {
+func (d *Driver) createIpc(container *configs.Config, c *execdriver.Command) error {
 	if c.Ipc.HostIpc {
 		container.Namespaces.Remove(configs.NEWIPC)
 		return nil
@@ -168,7 +168,7 @@ func (d *driver) createIpc(container *configs.Config, c *execdriver.Command) err
 	return nil
 }
 
-func (d *driver) createPid(container *configs.Config, c *execdriver.Command) error {
+func (d *Driver) createPid(container *configs.Config, c *execdriver.Command) error {
 	if c.Pid.HostPid {
 		container.Namespaces.Remove(configs.NEWPID)
 		return nil
@@ -177,7 +177,7 @@ func (d *driver) createPid(container *configs.Config, c *execdriver.Command) err
 	return nil
 }
 
-func (d *driver) createUTS(container *configs.Config, c *execdriver.Command) error {
+func (d *Driver) createUTS(container *configs.Config, c *execdriver.Command) error {
 	if c.UTS.HostUTS {
 		container.Namespaces.Remove(configs.NEWUTS)
 		container.Hostname = ""
@@ -187,7 +187,7 @@ func (d *driver) createUTS(container *configs.Config, c *execdriver.Command) err
 	return nil
 }
 
-func (d *driver) setPrivileged(container *configs.Config) (err error) {
+func (d *Driver) setPrivileged(container *configs.Config) (err error) {
 	container.Capabilities = execdriver.GetAllCapabilities()
 	container.Cgroups.AllowAllDevices = true
 
@@ -204,12 +204,12 @@ func (d *driver) setPrivileged(container *configs.Config) (err error) {
 	return nil
 }
 
-func (d *driver) setCapabilities(container *configs.Config, c *execdriver.Command) (err error) {
+func (d *Driver) setCapabilities(container *configs.Config, c *execdriver.Command) (err error) {
 	container.Capabilities, err = execdriver.TweakCapabilities(container.Capabilities, c.CapAdd, c.CapDrop)
 	return err
 }
 
-func (d *driver) setupRlimits(container *configs.Config, c *execdriver.Command) {
+func (d *Driver) setupRlimits(container *configs.Config, c *execdriver.Command) {
 	if c.Resources == nil {
 		return
 	}
@@ -223,7 +223,7 @@ func (d *driver) setupRlimits(container *configs.Config, c *execdriver.Command)
 	}
 }
 
-func (d *driver) setupMounts(container *configs.Config, c *execdriver.Command) error {
+func (d *Driver) setupMounts(container *configs.Config, c *execdriver.Command) error {
 	userMounts := make(map[string]struct{})
 	for _, m := range c.Mounts {
 		userMounts[m.Destination] = struct{}{}
@@ -260,7 +260,7 @@ func (d *driver) setupMounts(container *configs.Config, c *execdriver.Command) e
 	return nil
 }
 
-func (d *driver) setupLabels(container *configs.Config, c *execdriver.Command) {
+func (d *Driver) setupLabels(container *configs.Config, c *execdriver.Command) {
 	container.ProcessLabel = c.ProcessLabel
 	container.MountLabel = c.MountLabel
 }

daemon/execdriver/native/driver.go

@@ -27,12 +27,15 @@ import (
 	"github.com/opencontainers/runc/libcontainer/utils"
 )
 
+// Define constants for native driver
 const (
 	DriverName = "native"
 	Version    = "0.2"
 )
 
-type driver struct {
+// Driver contains all information for native driver,
+// it implements execdriver.Driver.
+type Driver struct {
 	root             string
 	initPath         string
 	activeContainers map[string]libcontainer.Container
@@ -41,7 +44,8 @@ type driver struct {
 	sync.Mutex
 }
 
-func NewDriver(root, initPath string, options []string) (*driver, error) {
+// NewDriver returns a new native driver, called from NewDriver of execdriver.
+func NewDriver(root, initPath string, options []string) (*Driver, error) {
 	meminfo, err := sysinfo.ReadMemInfo()
 	if err != nil {
 		return nil, err
@@ -96,7 +100,7 @@ func NewDriver(root, initPath string, options []string) (*driver, error) {
 		return nil, err
 	}
 
-	return &driver{
+	return &Driver{
 		root:             root,
 		initPath:         initPath,
 		activeContainers: make(map[string]libcontainer.Container),
@@ -110,7 +114,9 @@ type execOutput struct {
 	err      error
 }
 
-func (d *driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (execdriver.ExitStatus, error) {
+// Run implements the exec driver Driver interface,
+// it calls libcontainer APIs to run a container.
+func (d *Driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (execdriver.ExitStatus, error) {
 	// take the Command and populate the libcontainer.Config from it
 	container, err := d.createContainer(c)
 	if err != nil {
@@ -238,7 +244,8 @@ func waitInPIDHost(p *libcontainer.Process, c libcontainer.Container) func() (*o
 	}
 }
 
-func (d *driver) Kill(c *execdriver.Command, sig int) error {
+// Kill implements the exec driver Driver interface.
+func (d *Driver) Kill(c *execdriver.Command, sig int) error {
 	d.Lock()
 	active := d.activeContainers[c.ID]
 	d.Unlock()
@@ -252,7 +259,9 @@ func (d *driver) Kill(c *execdriver.Command, sig int) error {
 	return syscall.Kill(state.InitProcessPid, syscall.Signal(sig))
 }
 
-func (d *driver) Pause(c *execdriver.Command) error {
+// Pause implements the exec driver Driver interface,
+// it calls libcontainer API to pause a container.
+func (d *Driver) Pause(c *execdriver.Command) error {
 	d.Lock()
 	active := d.activeContainers[c.ID]
 	d.Unlock()
@@ -262,7 +271,9 @@ func (d *driver) Pause(c *execdriver.Command) error {
 	return active.Pause()
 }
 
-func (d *driver) Unpause(c *execdriver.Command) error {
+// Unpause implements the exec driver Driver interface,
+// it calls libcontainer API to unpause a container.
+func (d *Driver) Unpause(c *execdriver.Command) error {
 	d.Lock()
 	active := d.activeContainers[c.ID]
 	d.Unlock()
@@ -272,7 +283,8 @@ func (d *driver) Unpause(c *execdriver.Command) error {
 	return active.Resume()
 }
 
-func (d *driver) Terminate(c *execdriver.Command) error {
+// Terminate implements the exec driver Driver interface.
+func (d *Driver) Terminate(c *execdriver.Command) error {
 	defer d.cleanContainer(c.ID)
 	container, err := d.factory.Load(c.ID)
 	if err != nil {
@@ -295,18 +307,21 @@ func (d *driver) Terminate(c *execdriver.Command) error {
 	return err
 }
 
-func (d *driver) Info(id string) execdriver.Info {
+// Info implements the exec driver Driver interface.
+func (d *Driver) Info(id string) execdriver.Info {
 	return &info{
 		ID:     id,
 		driver: d,
 	}
 }
 
-func (d *driver) Name() string {
+// Name implements the exec driver Driver interface.
+func (d *Driver) Name() string {
 	return fmt.Sprintf("%s-%s", DriverName, Version)
 }
 
-func (d *driver) GetPidsForContainer(id string) ([]int, error) {
+// GetPidsForContainer implements the exec driver Driver interface.
+func (d *Driver) GetPidsForContainer(id string) ([]int, error) {
 	d.Lock()
 	active := d.activeContainers[id]
 	d.Unlock()
@@ -317,22 +332,24 @@ func (d *driver) GetPidsForContainer(id string) ([]int, error) {
 	return active.Processes()
 }
 
-func (d *driver) cleanContainer(id string) error {
+func (d *Driver) cleanContainer(id string) error {
 	d.Lock()
 	delete(d.activeContainers, id)
 	d.Unlock()
 	return os.RemoveAll(filepath.Join(d.root, id))
 }
 
-func (d *driver) createContainerRoot(id string) error {
+func (d *Driver) createContainerRoot(id string) error {
 	return os.MkdirAll(filepath.Join(d.root, id), 0655)
 }
 
-func (d *driver) Clean(id string) error {
+// Clean implements the exec driver Driver interface.
+func (d *Driver) Clean(id string) error {
 	return os.RemoveAll(filepath.Join(d.root, id))
 }
 
-func (d *driver) Stats(id string) (*execdriver.ResourceStats, error) {
+// Stats implements the exec driver Driver interface.
+func (d *Driver) Stats(id string) (*execdriver.ResourceStats, error) {
 	d.Lock()
 	c := d.activeContainers[id]
 	d.Unlock()
@@ -357,10 +374,12 @@ func (d *driver) Stats(id string) (*execdriver.ResourceStats, error) {
 	}, nil
 }
 
+// TtyConsole implements the exec driver Terminal interface.
 type TtyConsole struct {
 	console libcontainer.Console
 }
 
+// NewTtyConsole returns a new TtyConsole struct.
 func NewTtyConsole(console libcontainer.Console, pipes *execdriver.Pipes) (*TtyConsole, error) {
 	tty := &TtyConsole{
 		console: console,
@@ -374,10 +393,12 @@ func NewTtyConsole(console libcontainer.Console, pipes *execdriver.Pipes) (*TtyC
 	return tty, nil
 }
 
+// Resize implements Resize method of Terminal interface
 func (t *TtyConsole) Resize(h, w int) error {
 	return term.SetWinsize(t.console.Fd(), &term.Winsize{Height: uint16(h), Width: uint16(w)})
 }
 
+// AttachPipes attaches given pipes to TtyConsole
 func (t *TtyConsole) AttachPipes(pipes *execdriver.Pipes) error {
 	go func() {
 		if wb, ok := pipes.Stdout.(interface {
@@ -400,6 +421,7 @@ func (t *TtyConsole) AttachPipes(pipes *execdriver.Pipes) error {
 	return nil
 }
 
+// Close implements Close method of Terminal interface
 func (t *TtyConsole) Close() error {
 	return t.console.Close()
 }

daemon/execdriver/native/driver_unsupported.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/docker/daemon/execdriver"
 )
 
+// NewDriver returns a new native driver, called from NewDriver of execdriver.
 func NewDriver(root, initPath string) (execdriver.Driver, error) {
 	return nil, fmt.Errorf("native driver not supported on non-linux")
 }

daemon/execdriver/native/driver_unsupported_nocgo.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/docker/daemon/execdriver"
 )
 
+// NewDriver returns a new native driver, called from NewDriver of execdriver.
 func NewDriver(root, initPath string) (execdriver.Driver, error) {
 	return nil, fmt.Errorf("native driver not supported on non-linux")
 }

daemon/execdriver/native/exec.go

@@ -10,12 +10,17 @@ import (
 
 	"github.com/docker/docker/daemon/execdriver"
 	"github.com/opencontainers/runc/libcontainer"
+	// Blank import 'nsenter' so that init in that package will call c
+	// function 'nsexec()' to do 'setns' before Go runtime take over,
+	// it's used for join to exist ns like 'docker exec' command.
 	_ "github.com/opencontainers/runc/libcontainer/nsenter"
 	"github.com/opencontainers/runc/libcontainer/utils"
 )
 
+// Exec implements the exec driver Driver interface,
+// it calls libcontainer APIs to execute a container.
 // TODO(vishh): Add support for running in privileged mode.
-func (d *driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
+func (d *Driver) Exec(c *execdriver.Command, processConfig *execdriver.ProcessConfig, pipes *execdriver.Pipes, startCallback execdriver.StartCallback) (int, error) {
 	active := d.activeContainers[c.ID]
 	if active == nil {
 		return -1, fmt.Errorf("No active container exists with ID %s", c.ID)

daemon/execdriver/native/info.go

@@ -4,7 +4,7 @@ package native
 
 type info struct {
 	ID     string
-	driver *driver
+	driver *Driver
 }
 
 // IsRunning is determined by looking for the

daemon/execdriver/pipes.go

@@ -4,13 +4,14 @@ import (
 	"io"
 )
 
-// Pipes is a wrapper around a containers output for
+// Pipes is a wrapper around a container's output for
 // stdin, stdout, stderr
 type Pipes struct {
 	Stdin          io.ReadCloser
 	Stdout, Stderr io.Writer
 }
 
+// NewPipes returns a wrapper around a container's output
 func NewPipes(stdin io.ReadCloser, stdout, stderr io.Writer, useStdin bool) *Pipes {
 	p := &Pipes{
 		Stdout: stdout,

daemon/execdriver/termconsole.go

@@ -5,9 +5,11 @@ import (
 	"os/exec"
 )
 
+// StdConsole defines standard console operations for execdriver
 type StdConsole struct {
 }
 
+// NewStdConsole returns a new StdConsole struct
 func NewStdConsole(processConfig *ProcessConfig, pipes *Pipes) (*StdConsole, error) {
 	std := &StdConsole{}
 
@@ -17,6 +19,7 @@ func NewStdConsole(processConfig *ProcessConfig, pipes *Pipes) (*StdConsole, err
 	return std, nil
 }
 
+// AttachPipes attaches given pipes to exec.Cmd
 func (s *StdConsole) AttachPipes(command *exec.Cmd, pipes *Pipes) error {
 	command.Stdout = pipes.Stdout
 	command.Stderr = pipes.Stderr
@@ -35,11 +38,13 @@ func (s *StdConsole) AttachPipes(command *exec.Cmd, pipes *Pipes) error {
 	return nil
 }
 
+// Resize implements Resize method of Terminal interface
 func (s *StdConsole) Resize(h, w int) error {
 	// we do not need to reside a non tty
 	return nil
 }
 
+// Close implements Close method of Terminal interface
 func (s *StdConsole) Close() error {
 	// nothing to close here
 	return nil

daemon/execdriver/utils.go

@@ -30,17 +30,24 @@ func init() {
 }
 
 type (
+	// CapabilityMapping maps linux capability name to its value of capability.Cap type
+	// Capabilities is one of the security systems in Linux Security Module (LSM)
+	// framework provided by the kernel.
+	// For more details on capabilities, see http://man7.org/linux/man-pages/man7/capabilities.7.html
 	CapabilityMapping struct {
 		Key   string         `json:"key,omitempty"`
 		Value capability.Cap `json:"value,omitempty"`
 	}
+	// Capabilities contains all CapabilityMapping
 	Capabilities []*CapabilityMapping
 )
 
+// String returns <key> of CapabilityMapping
 func (c *CapabilityMapping) String() string {
 	return c.Key
 }
 
+// GetCapability returns CapabilityMapping which contains specific key
 func GetCapability(key string) *CapabilityMapping {
 	for _, capp := range capabilityList {
 		if capp.Key == key {
@@ -51,6 +58,7 @@ func GetCapability(key string) *CapabilityMapping {
 	return nil
 }
 
+// GetAllCapabilities returns all of the capabilities
 func GetAllCapabilities() []string {
 	output := make([]string, len(capabilityList))
 	for i, capability := range capabilityList {
@@ -59,6 +67,8 @@ func GetAllCapabilities() []string {
 	return output
 }
 
+// TweakCapabilities can tweak capabilities by adding or dropping capabilities
+// based on the basics capabilities.
 func TweakCapabilities(basics, adds, drops []string) ([]string, error) {
 	var (
 		newCaps []string

daemon/execdriver/windows/unsupported.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/docker/daemon/execdriver"
 )
 
+// NewDriver returns a new execdriver.Driver
 func NewDriver(root, initPath string) (execdriver.Driver, error) {
 	return nil, fmt.Errorf("Windows driver not supported on non-Windows")
 }