RuntimeCkpt is now State and the checkpoint file is called state.json.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

api.go

@@ -6,14 +6,14 @@ import (
 )
 
 // Returns all available stats for the given container.
-func GetContainerStats(container *Config, runtimeCkpt *RuntimeCkpt) (*ContainerStats, error) {
+func GetContainerStats(container *Config, state *State) (*ContainerStats, error) {
 	containerStats := NewContainerStats()
 	stats, err := fs.GetStats(container.Cgroups)
 	if err != nil {
 		return containerStats, err
 	}
 	containerStats.CgroupStats = stats
-	networkStats, err := network.GetStats(&runtimeCkpt.NetworkCkpt)
+	networkStats, err := network.GetStats(&state.NetworkState)
 	if err != nil {
 		return containerStats, err
 	}

namespaces/exec.go

@@ -57,18 +57,6 @@ func Exec(container *libcontainer.Config, term Terminal, rootfs, dataPath string
 		return -1, err
 	}
 
-	state := &libcontainer.State{
-		InitPid:       command.Process.Pid,
-		InitStartTime: started,
-	}
-
-	if err := libcontainer.SaveState(dataPath, state); err != nil {
-		command.Process.Kill()
-		command.Wait()
-		return -1, err
-	}
-	defer libcontainer.DeleteState(dataPath)
-
 	// Do this before syncing with child so that no children
 	// can escape the cgroup
 	cleaner, err := SetupCgroups(container, command.Process.Pid)
@@ -87,12 +75,18 @@ func Exec(container *libcontainer.Config, term Terminal, rootfs, dataPath string
 		return -1, err
 	}
 
-	// Update the runtime checkpoint.
-	if err = libcontainer.UpdateRuntimeCkpt(dataPath); err != nil {
+	state := &libcontainer.State{
+		InitPid:       command.Process.Pid,
+		InitStartTime: started,
+		NetworkState:  *network.NetworkStateImpl.GetNetworkState(),
+	}
+
+	if err := libcontainer.SaveState(dataPath, state); err != nil {
 		command.Process.Kill()
 		command.Wait()
 		return -1, err
 	}
+	defer libcontainer.DeleteState(dataPath)
 
 	// Sync with child
 	syncPipe.Close()

network/state.go

@@ -0,0 +1,25 @@
+package network
+
+// Struct describing the network specific runtime state that will be maintained by libcontainer for all running containers
+// Do not depend on it outside of libcontainer.
+type NetworkState struct {
+	// The name of the veth interface on the Host.
+	VethHost string `json:"veth_host,omitempty"`
+	// The name of the veth interface created inside the container for the child.
+	VethChild string `json:"veth_child,omitempty"`
+}
+
+type networkStateIntImpl struct{}
+
+var (
+	networkState     = &NetworkState{}
+	NetworkStateImpl = &networkStateIntImpl{}
+)
+
+func (networkStateIntImpl) GetNetworkState() *NetworkState {
+	return networkState
+}
+
+func (networkStateIntImpl) updateNetworkState(n *NetworkState) {
+	networkState = n
+}

network/stats.go

@@ -20,12 +20,12 @@ type NetworkStats struct {
 }
 
 // Returns the network statistics for the network interfaces represented by the NetworkRuntimeInfo.
-func GetStats(networkCkpt *NetworkCkpt) (NetworkStats, error) {
+func GetStats(networkState *NetworkState) (NetworkStats, error) {
 	// This can happen if the network runtime information is missing - possible if the container was created by an old version of libcontainer.
-	if networkCkpt.VethHost == "" {
+	if networkState.VethHost == "" {
 		return NetworkStats{}, nil
 	}
-	data, err := readSysfsNetworkStats(networkCkpt.VethHost)
+	data, err := readSysfsNetworkStats(networkState.VethHost)
 	if err != nil {
 		return NetworkStats{}, err
 	}

network/veth.go

@@ -45,10 +45,10 @@ func (v *Veth) Create(n *Network, nspid int, context map[string]string, dataPath
 	if err := SetInterfaceInNamespacePid(name2, nspid); err != nil {
 		return err
 	}
-	networkCkpt := NetworkCkptImpl.GetNetworkCkpt()
-	networkCkpt.VethHost = name1
-	networkCkpt.VethChild = name2
-	NetworkCkptImpl.updateNetworkCkpt(networkCkpt)
+	networkState := NetworkStateImpl.GetNetworkState()
+	networkState.VethHost = name1
+	networkState.VethChild = name2
+	NetworkStateImpl.updateNetworkState(networkState)
 	return nil
 }
 

nsinit/stats.go

@@ -21,7 +21,7 @@ func statsAction(context *cli.Context) {
 		log.Fatal(err)
 	}
 
-	runtimeCkpt, err := libcontainer.GetRuntimeCkpt(dataPath)
+	runtimeCkpt, err := libcontainer.GetState(dataPath)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -35,8 +35,8 @@ func statsAction(context *cli.Context) {
 }
 
 // returns the container stats in json format.
-func getContainerStats(container *libcontainer.Config, runtimeCkpt *libcontainer.RuntimeCkpt) (string, error) {
-	stats, err := libcontainer.GetContainerStats(container, runtimeCkpt)
+func getContainerStats(container *libcontainer.Config, state *libcontainer.State) (string, error) {
+	stats, err := libcontainer.GetContainerStats(container, state)
 	if err != nil {
 		return "", err
 	}

state.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
+
+	"github.com/docker/libcontainer/network"
 )
 
 // State represents a running container's state
@@ -12,12 +14,17 @@ type State struct {
 	InitPid int `json:"init_pid,omitempty"`
 	// InitStartTime is the init process start time
 	InitStartTime string `json:"init_start_time,omitempty"`
+	// Network runtime state.
+	NetworkState network.NetworkState `json:"network_state,omitempty"`
 }
 
+// The name of the runtime state file
+const stateFile = "state.json"
+
 // SaveState writes the container's runtime state to a state.json file
 // in the specified path
 func SaveState(basePath string, state *State) error {
-	f, err := os.Create(filepath.Join(basePath, "state.json"))
+	f, err := os.Create(filepath.Join(basePath, stateFile))
 	if err != nil {
 		return err
 	}
@@ -28,7 +35,7 @@ func SaveState(basePath string, state *State) error {
 
 // GetState reads the state.json file for a running container
 func GetState(basePath string) (*State, error) {
-	f, err := os.Open(filepath.Join(basePath, "state.json"))
+	f, err := os.Open(filepath.Join(basePath, stateFile))
 	if err != nil {
 		return nil, err
 	}
@@ -44,5 +51,5 @@ func GetState(basePath string) (*State, error) {
 
 // DeleteState deletes the state.json file
 func DeleteState(basePath string) error {
-	return os.Remove(filepath.Join(basePath, "state.json"))
+	return os.Remove(filepath.Join(basePath, stateFile))
 }