persist: demo code for persist api

Demonstrate how to make use of `virtcontainer/persist/api` data structure
package.

Signed-off-by: Wei Zhang <zhangwei555@huawei.com>

virtcontainers/api.go

@@ -224,6 +224,10 @@ func StartSandbox(ctx context.Context, sandboxID string) (VCSandbox, error) {
 		return nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
+
 	return s, nil
 }
 
@@ -256,6 +260,10 @@ func StopSandbox(ctx context.Context, sandboxID string) (VCSandbox, error) {
 		return nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
+
 	return s, nil
 }
 
@@ -394,6 +402,10 @@ func CreateContainer(ctx context.Context, sandboxID string, containerConfig Cont
 		return nil, nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, nil, err
+	}
+
 	return s, c, nil
 }
 

virtcontainers/container.go

@@ -374,6 +374,9 @@ func (c *Container) GetAnnotations() map[string]string {
 
 // storeContainer stores a container config.
 func (c *Container) storeContainer() error {
+	if err := c.sandbox.newStore.Dump(); err != nil {
+		return err
+	}
 	return c.store.Store(store.Configuration, *(c.config))
 }
 

virtcontainers/container_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/kata-containers/runtime/virtcontainers/device/config"
 	"github.com/kata-containers/runtime/virtcontainers/device/drivers"
 	"github.com/kata-containers/runtime/virtcontainers/device/manager"
+	"github.com/kata-containers/runtime/virtcontainers/persist"
 	"github.com/kata-containers/runtime/virtcontainers/store"
 	"github.com/kata-containers/runtime/virtcontainers/types"
 	"github.com/stretchr/testify/assert"
@@ -247,6 +248,10 @@ func TestContainerAddDriveDir(t *testing.T) {
 	assert.Nil(t, err)
 	container.store = containerStore
 
+	if sandbox.newStore, err = persist.GetDriver("fs"); err != nil || sandbox.newStore == nil {
+		t.Fatalf("failed to get fs persist driver")
+	}
+
 	// create state file
 	path := store.ContainerRuntimeRootPath(testSandboxID, container.ID())
 	stateFilePath := filepath.Join(path, store.StateFile)

virtcontainers/persist.go

@@ -0,0 +1,96 @@
+// Copyright (c) 2018 Huawei Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package virtcontainers
+
+import (
+	//"fmt"
+
+	//"github.com/sirupsen/logrus"
+
+	persistapi "github.com/kata-containers/runtime/virtcontainers/persist/api"
+	"github.com/kata-containers/runtime/virtcontainers/types"
+)
+
+func (s *Sandbox) dumpState(ss *persistapi.SandboxState, cs map[string]persistapi.ContainerState) error {
+	ss.SandboxContainer = s.id
+	ss.GuestMemoryBlockSizeMB = s.state.GuestMemoryBlockSizeMB
+	ss.State = string(s.state.State)
+
+	for id, cont := range s.containers {
+		cs[id] = persistapi.ContainerState{
+			State: string(cont.state.State),
+			Rootfs: persistapi.RootfsState{
+				BlockDeviceID: cont.state.BlockDeviceID,
+				FsType:        cont.state.Fstype,
+			},
+		}
+	}
+	return nil
+}
+
+func (s *Sandbox) dumpHypervisor(ss *persistapi.SandboxState, cs map[string]persistapi.ContainerState) error {
+	ss.HypervisorState.BlockIndex = s.state.BlockIndex
+	return nil
+}
+
+// PersistVersion set persist data version to current version in runtime
+func (s *Sandbox) persistVersion() {
+	s.newStore.RegisterHook("version", func(ss *persistapi.SandboxState, cs map[string]persistapi.ContainerState) error {
+		ss.PersistVersion = persistapi.CurPersistVersion
+		return nil
+	})
+}
+
+// PersistState register hook to set sandbox and container state to persist
+func (s *Sandbox) persistState() {
+	s.newStore.RegisterHook("state", s.dumpState)
+}
+
+// PersistHvState register hook to save hypervisor state to persist data
+func (s *Sandbox) persistHvState() {
+	s.newStore.RegisterHook("hypervisor", s.dumpHypervisor)
+}
+
+// Restore will restore data from persist disk on disk
+func (s *Sandbox) Restore() error {
+	if err := s.newStore.Restore(s.id); err != nil {
+		return err
+	}
+
+	ss, _, err := s.newStore.GetStates()
+	if err != nil {
+		return err
+	}
+
+	/*
+		// TODO: need more modifications, restoring containers
+		// will make sandbox.addContainer failing
+		if s.containers == nil {
+			s.containers = make(map[string]*Container)
+		}
+
+		for id, cont := range cs {
+			s.containers[id] = &Container{
+				state: State{
+					State:         stateString(cont.State),
+					BlockDeviceID: cont.Rootfs.BlockDeviceID,
+					Fstype:        cont.Rootfs.FsType,
+					Pid:           cont.ShimPid,
+				},
+			}
+		}
+
+		sbxCont, ok := s.containers[ss.SandboxContainer]
+		if !ok {
+			return fmt.Errorf("failed to get sandbox container state")
+		}
+	*/
+	s.state.GuestMemoryBlockSizeMB = ss.GuestMemoryBlockSizeMB
+	s.state.BlockIndex = ss.HypervisorState.BlockIndex
+	s.state.State = types.StateString(ss.State)
+
+	return nil
+}

virtcontainers/persist/api/interface.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2018 Huawei Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package persistapi
+
+// PersistDriver is interface describing operations to save/restore persist data
+type PersistDriver interface {
+	// Dump persist data to
+	Dump() error
+	Restore(sid string) error
+	Destroy() error
+	GetStates() (*SandboxState, map[string]ContainerState, error)
+	RegisterHook(name string, f SetFunc)
+}

virtcontainers/persist/fs/fs.go

@@ -0,0 +1,270 @@
+// Copyright (c) 2016 Intel Corporation
+// Copyright (c) 2018 Huawei Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package fs
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	persistapi "github.com/kata-containers/runtime/virtcontainers/persist/api"
+)
+
+// persistFile is the file name for JSON sandbox/container configuration
+const persistFile = "persist.json"
+
+// dirMode is the permission bits used for creating a directory
+const dirMode = os.FileMode(0750)
+
+// fileMode is the permission bits used for creating a file
+const fileMode = os.FileMode(0640)
+
+// storagePathSuffix is the suffix used for all storage paths
+//
+// Note: this very brief path represents "virtcontainers". It is as
+// terse as possible to minimise path length.
+const storagePathSuffix = "vc"
+
+// sandboxPathSuffix is the suffix used for sandbox storage
+const sandboxPathSuffix = "sbs"
+
+// runStoragePath is the sandbox runtime directory.
+// It will contain one state.json and one lock file for each created sandbox.
+var runStoragePath = filepath.Join("/run", storagePathSuffix, sandboxPathSuffix)
+
+// FS storage driver implementation
+type FS struct {
+	sandboxState   *persistapi.SandboxState
+	containerState map[string]persistapi.ContainerState
+	setFuncs       map[string]persistapi.SetFunc
+
+	lockFile *os.File
+}
+
+// Name returns driver name
+func Name() string {
+	return "fs"
+}
+
+// Init FS persist driver and return abstract PersistDriver
+func Init() (persistapi.PersistDriver, error) {
+	return &FS{
+		sandboxState:   &persistapi.SandboxState{},
+		containerState: make(map[string]persistapi.ContainerState),
+		setFuncs:       make(map[string]persistapi.SetFunc),
+	}, nil
+}
+
+func (fs *FS) sandboxDir() (string, error) {
+	if fs.sandboxState.SandboxContainer == "" {
+		return "", fmt.Errorf("sandbox container id required")
+	}
+
+	return filepath.Join(runStoragePath, fs.sandboxState.SandboxContainer), nil
+}
+
+// Dump sandboxState and containerState to disk
+func (fs *FS) Dump() (retErr error) {
+	// call registered hooks to set sandboxState and containerState
+	for _, fun := range fs.setFuncs {
+		fun(fs.sandboxState, fs.containerState)
+	}
+
+	// if error happened, destroy all dirs
+	defer func() {
+		if retErr != nil {
+			// TODO: log error
+			fs.Destroy()
+		}
+	}()
+
+	sandboxDir, err := fs.sandboxDir()
+	if err != nil {
+		return err
+	}
+
+	if err := os.MkdirAll(sandboxDir, dirMode); err != nil {
+		return err
+	}
+
+	if err := fs.lock(); err != nil {
+		return err
+	}
+	defer fs.unlock()
+
+	// persist sandbox configuration data
+	sandboxFile := filepath.Join(sandboxDir, persistFile)
+	f, err := os.OpenFile(sandboxFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, fileMode)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if err := json.NewEncoder(f).Encode(fs.sandboxState); err != nil {
+		return err
+	}
+
+	// persist container configuration data
+	for cid, cstate := range fs.containerState {
+		cdir := filepath.Join(sandboxDir, cid)
+		if err := os.MkdirAll(cdir, dirMode); err != nil {
+			return err
+		}
+
+		cfile := filepath.Join(cdir, persistFile)
+		cf, err := os.OpenFile(cfile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, fileMode)
+		if err != nil {
+			return err
+		}
+
+		if err := json.NewEncoder(cf).Encode(cstate); err != nil {
+			return err
+		}
+		cf.Close()
+	}
+
+	return nil
+}
+
+// Restore state for sandbox with name sid
+func (fs *FS) Restore(sid string) error {
+	if sid == "" {
+		return fmt.Errorf("restore requires sandbox id")
+	}
+
+	fs.sandboxState.SandboxContainer = sid
+	sandboxDir, err := fs.sandboxDir()
+	if err != nil {
+		return err
+	}
+
+	if err := os.MkdirAll(sandboxDir, dirMode); err != nil {
+		return err
+	}
+
+	if err := fs.lock(); err != nil {
+		return err
+	}
+	defer fs.unlock()
+
+	// get sandbox configuration from persist data
+	sandboxFile := filepath.Join(sandboxDir, persistFile)
+	f, err := os.OpenFile(sandboxFile, os.O_RDONLY, fileMode)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if err := json.NewDecoder(f).Decode(fs.sandboxState); err != nil {
+		return err
+	}
+
+	// walk sandbox dir and find container
+	d, err := os.OpenFile(sandboxDir, os.O_RDONLY, fileMode)
+	if err != nil {
+		return err
+	}
+	defer d.Close()
+
+	files, err := d.Readdir(-1)
+	if err != nil {
+		return err
+	}
+
+	for _, file := range files {
+		if !file.IsDir() {
+			continue
+		}
+
+		cid := file.Name()
+		cfile := filepath.Join(sandboxDir, cid, persistFile)
+		cf, err := os.OpenFile(cfile, os.O_RDONLY, fileMode)
+		if err != nil {
+			// if persist.json doesn't exist, ignore and go to next
+			if os.IsNotExist(err) {
+				continue
+			}
+			return err
+		}
+
+		var cstate persistapi.ContainerState
+		if err := json.NewDecoder(cf).Decode(&cstate); err != nil {
+			return err
+		}
+		cf.Close()
+
+		fs.containerState[cid] = cstate
+	}
+	return nil
+}
+
+// Destroy removes everything from disk
+func (fs *FS) Destroy() error {
+	sandboxDir, err := fs.sandboxDir()
+	if err != nil {
+		return err
+	}
+
+	if err := os.RemoveAll(sandboxDir); err != nil {
+		return err
+	}
+	return nil
+}
+
+// GetStates returns SandboxState and ContainerState
+func (fs *FS) GetStates() (*persistapi.SandboxState, map[string]persistapi.ContainerState, error) {
+	return fs.sandboxState, fs.containerState, nil
+}
+
+// RegisterHook registers processing hooks for Dump
+func (fs *FS) RegisterHook(name string, f persistapi.SetFunc) {
+	// only accept last registered hook with same name
+	fs.setFuncs[name] = f
+}
+
+func (fs *FS) lock() error {
+	sandboxDir, err := fs.sandboxDir()
+	if err != nil {
+		return err
+	}
+
+	f, err := os.Open(sandboxDir)
+	if err != nil {
+		return err
+	}
+
+	if err := syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
+		f.Close()
+		return err
+	}
+	fs.lockFile = f
+
+	return nil
+}
+
+func (fs *FS) unlock() error {
+	if fs.lockFile == nil {
+		return nil
+	}
+
+	lockFile := fs.lockFile
+	defer lockFile.Close()
+	fs.lockFile = nil
+	if err := syscall.Flock(int(lockFile.Fd()), syscall.LOCK_UN); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// TestSetRunStoragePath set runStoragePath to path
+// this function is only used for testing purpose
+func TestSetRunStoragePath(path string) {
+	runStoragePath = path
+}

virtcontainers/persist/manager.go

@@ -0,0 +1,31 @@
+// Copyright (c) 2018 Huawei Corporation
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package persist
+
+import (
+	"fmt"
+
+	"github.com/kata-containers/runtime/virtcontainers/persist/api"
+	"github.com/kata-containers/runtime/virtcontainers/persist/fs"
+)
+
+type initFunc (func() (persistapi.PersistDriver, error))
+
+var (
+	supportedDrivers = map[string]initFunc{
+		"fs": fs.Init,
+	}
+	defaultDriver = "fs"
+)
+
+// GetDriver returns new PersistDriver according to driver name
+func GetDriver(name string) (persistapi.PersistDriver, error) {
+	if f, ok := supportedDrivers[name]; ok {
+		return f()
+	}
+
+	return nil, fmt.Errorf("failed to get storage driver %q", name)
+}

virtcontainers/persist/plugin/README.md

@@ -0,0 +1,2 @@
+This package is a simple placeholder currently which will contain persist storage plugin support,
+e.g. leveldb, sqlite and other possible storage implementations.

virtcontainers/sandbox.go

@@ -27,6 +27,8 @@ import (
 	"github.com/kata-containers/runtime/virtcontainers/device/drivers"
 	deviceManager "github.com/kata-containers/runtime/virtcontainers/device/manager"
 	exp "github.com/kata-containers/runtime/virtcontainers/experimental"
+	"github.com/kata-containers/runtime/virtcontainers/persist"
+	persistapi "github.com/kata-containers/runtime/virtcontainers/persist/api"
 	"github.com/kata-containers/runtime/virtcontainers/pkg/annotations"
 	vcTypes "github.com/kata-containers/runtime/virtcontainers/pkg/types"
 	"github.com/kata-containers/runtime/virtcontainers/store"
@@ -159,8 +161,11 @@ type Sandbox struct {
 	hypervisor hypervisor
 	agent      agent
 	store      *store.VCStore
-	network    Network
+	// store is used to replace VCStore step by step
-	monitor    *monitor
+	newStore persistapi.PersistDriver
+
+	network Network
+	monitor *monitor
 
 	config *SandboxConfig
 
@@ -472,15 +477,25 @@ func createSandbox(ctx context.Context, sandboxConfig SandboxConfig, factory Fac
 	}
 	s.devManager = deviceManager.NewDeviceManager(sandboxConfig.HypervisorConfig.BlockDeviceDriver, devices)
 
+	// register persist hook for now, data will be written to disk by Dump()
+	s.persistState()
+	s.persistHvState()
+
+	if err := s.Restore(); err == nil && s.state.State != "" {
+		return s, nil
+	}
 	// We first try to fetch the sandbox state from storage.
 	// If it exists, this means this is a re-creation, i.e.
 	// we don't need to talk to the guest's agent, but only
 	// want to create the sandbox and its containers in memory.
-	state, err := s.store.LoadState()
+	/* state, err := s.store.LoadState()
 	if err == nil && state.State != "" {
 		s.state = state
 		return s, nil
-	}
+	}*/
+
+	// if sandbox doesn't exist, set persist version to current version
+	s.persistVersion()
 
 	// Below code path is called only during create, because of earlier check.
 	if err := s.agent.createSandbox(s); err != nil {
@@ -536,6 +551,10 @@ func newSandbox(ctx context.Context, sandboxConfig SandboxConfig, factory Factor
 
 	s.store = vcStore
 
+	if s.newStore, err = persist.GetDriver("fs"); err != nil || s.newStore == nil {
+		return nil, fmt.Errorf("failed to get fs persist driver")
+	}
+
 	if err = globalSandboxList.addSandbox(s); err != nil {
 		return nil, err
 	}
@@ -586,6 +605,10 @@ func (s *Sandbox) storeSandbox() error {
 		}
 	}
 
+	if err = s.newStore.Dump(); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -1078,6 +1101,10 @@ func (s *Sandbox) CreateContainer(contConfig ContainerConfig) (VCContainer, erro
 		return nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
+
 	return c, nil
 }
 
@@ -1094,6 +1121,11 @@ func (s *Sandbox) StartContainer(containerID string) (VCContainer, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
+
 	//Fixme Container delete from sandbox, need to update resources
 
 	return c, nil
@@ -1112,6 +1144,9 @@ func (s *Sandbox) StopContainer(containerID string) (VCContainer, error) {
 		return nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
 	return c, nil
 }
 
@@ -1124,7 +1159,14 @@ func (s *Sandbox) KillContainer(containerID string, signal syscall.Signal, all b
 	}
 
 	// Send a signal to the process.
-	return c.kill(signal, all)
+	if err := c.kill(signal, all); err != nil {
+		return err
+	}
+
+	if err = s.storeSandbox(); err != nil {
+		return err
+	}
+	return nil
 }
 
 // DeleteContainer deletes a container from the sandbox
@@ -1158,6 +1200,9 @@ func (s *Sandbox) DeleteContainer(containerID string) (VCContainer, error) {
 		return nil, err
 	}
 
+	if err = s.storeSandbox(); err != nil {
+		return nil, err
+	}
 	return c, nil
 }
 
@@ -1236,7 +1281,13 @@ func (s *Sandbox) UpdateContainer(containerID string, resources specs.LinuxResou
 		return err
 	}
 
-	return c.storeContainer()
+	if err := c.storeContainer(); err != nil {
+		return err
+	}
+	if err = s.storeSandbox(); err != nil {
+		return err
+	}
+	return nil
 }
 
 // StatsContainer return the stats of a running container
@@ -1263,7 +1314,14 @@ func (s *Sandbox) PauseContainer(containerID string) error {
 	}
 
 	// Pause the container.
-	return c.pause()
+	if err := c.pause(); err != nil {
+		return err
+	}
+
+	if err = s.storeSandbox(); err != nil {
+		return err
+	}
+	return nil
 }
 
 // ResumeContainer resumes a paused container.
@@ -1275,7 +1333,14 @@ func (s *Sandbox) ResumeContainer(containerID string) error {
 	}
 
 	// Resume the container.
-	return c.resume()
+	if err := c.resume(); err != nil {
+		return err
+	}
+
+	if err = s.storeSandbox(); err != nil {
+		return err
+	}
+	return nil
 }
 
 // createContainers registers all containers to the proxy, create the
@@ -1306,6 +1371,9 @@ func (s *Sandbox) createContainers() error {
 	if err := s.updateCgroups(); err != nil {
 		return err
 	}
+	if err := s.storeSandbox(); err != nil {
+		return err
+	}
 
 	return nil
 }
@@ -1327,6 +1395,10 @@ func (s *Sandbox) Start() error {
 		}
 	}
 
+	if err := s.storeSandbox(); err != nil {
+		return err
+	}
+
 	s.Logger().Info("Sandbox is started")
 
 	return nil
@@ -1362,7 +1434,15 @@ func (s *Sandbox) Stop() error {
 	}
 
 	// Remove the network.
-	return s.removeNetwork()
+	if err := s.removeNetwork(); err != nil {
+		return err
+	}
+
+	if err := s.storeSandbox(); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 // Pause pauses the sandbox
@@ -1379,7 +1459,15 @@ func (s *Sandbox) Pause() error {
 		s.monitor.stop()
 	}
 
-	return s.pauseSetStates()
+	if err := s.pauseSetStates(); err != nil {
+		return err
+	}
+
+	if err := s.storeSandbox(); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 // Resume resumes the sandbox
@@ -1388,7 +1476,15 @@ func (s *Sandbox) Resume() error {
 		return err
 	}
 
-	return s.resumeSetStates()
+	if err := s.resumeSetStates(); err != nil {
+		return err
+	}
+
+	if err := s.storeSandbox(); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 // list lists all sandbox running on the host.

virtcontainers/virtcontainers_test.go

@@ -14,6 +14,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/kata-containers/runtime/virtcontainers/persist/fs"
 	"github.com/kata-containers/runtime/virtcontainers/store"
 	"github.com/sirupsen/logrus"
 )
@@ -104,6 +105,7 @@ func TestMain(m *testing.M) {
 	// allow the tests to run without affecting the host system.
 	store.ConfigStoragePath = filepath.Join(testDir, store.StoragePathSuffix, "config")
 	store.RunStoragePath = filepath.Join(testDir, store.StoragePathSuffix, "run")
+	fs.TestSetRunStoragePath(filepath.Join(testDir, "vc", "sbs"))
 
 	// set now that configStoragePath has been overridden.
 	sandboxDirConfig = filepath.Join(store.ConfigStoragePath, testSandboxID)