Make 'pod' package to use unified checkpointManager

Signed-off-by: vikaschoudhary16 <choudharyvikas16@gmail.com>

pkg/kubelet/checkpointmanager/BUILD

@@ -22,7 +22,7 @@ go_test(
     srcs = ["checkpoint_manager_test.go"],
     embed = [":go_default_library"],
     deps = [
-        "//pkg/kubelet/checkpointmanager/errors:go_default_library",
+        "//pkg/kubelet/checkpointmanager/checksum:go_default_library",
         "//pkg/kubelet/checkpointmanager/testing:go_default_library",
         "//pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1:go_default_library",
         "//vendor/github.com/stretchr/testify/assert:go_default_library",

pkg/kubelet/checkpointmanager/README.md

@@ -1,8 +1,9 @@
 ## DISCLAIMER
-Sig-Node community has reached a general consensus, as a best practice, to
+- Sig-Node community has reached a general consensus, as a best practice, to
 avoid introducing any new checkpointing support. We reached this understanding
 after struggling with some hard-to-debug issues in the production environments
 caused by the checkpointing.
+- Any changes to the checkpointed data structure would be considered incompatible and a component should add its own handling if it needs to ensure backward compatibility of reading old-format checkpoint files.
 
 ## Introduction
 This folder contains a framework & primitives, Checkpointing Manager, which is

pkg/kubelet/checkpointmanager/checkpoint_manager.go

@@ -18,6 +18,7 @@ package checkpointmanager
 
 import (
 	"fmt"
+	"sync"
 
 	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
 	utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
@@ -48,8 +49,10 @@ type CheckpointManager interface {
 type impl struct {
 	path  string
 	store utilstore.Store
+	mutex sync.Mutex
 }
 
+// NewCheckpointManager returns a new instance of a checkpoint manager
 func NewCheckpointManager(checkpointDir string) (CheckpointManager, error) {
 	fstore, err := utilstore.NewFileStore(checkpointDir, utilfs.DefaultFs{})
 	if err != nil {
@@ -88,6 +91,7 @@ func (manager *impl) GetCheckpoint(checkpointKey string, checkpoint Checkpoint)
 	return err
 }
 
+// RemoveCheckpoint will not return error if checkpoint does not exist.
 func (manager *impl) RemoveCheckpoint(checkpointKey string) error {
 	manager.mutex.Lock()
 	defer manager.mutex.Unlock()

pkg/kubelet/checkpointmanager/checkpoint_manager_test.go

@@ -18,12 +18,11 @@ package checkpointmanager
 
 import (
 	"encoding/json"
-	"hash/fnv"
 	"sort"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
-	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/errors"
+	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/checksum"
 	utilstore "k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing"
 	"k8s.io/kubernetes/pkg/kubelet/checkpointmanager/testing/example_checkpoint_formats/v1"
 )
@@ -50,7 +49,7 @@ type CheckpointDataV2 struct {
 type protocol string
 
 // portMapping is the port mapping configurations of a sandbox.
-type portMapping struct {
+type PortMapping struct {
 	// protocol of the port mapping.
 	Protocol *protocol
 	// Port number within the container.
@@ -153,7 +152,7 @@ func TestCheckpointManager(t *testing.T) {
 	port443 := int32(443)
 	proto := protocol("tcp")
 
-	portMappings := []*portMapping{
+	portMappings := []*PortMapping{
 		{
 			&proto,
 			&port80,

pkg/kubelet/checkpointmanager/errors/errors.go

@@ -18,5 +18,8 @@ package errors
 
 import "fmt"
 
-var CorruptCheckpointError = fmt.Errorf("checkpoint is corrupted.")
-var CheckpointNotFoundError = fmt.Errorf("checkpoint is not found.")
+// ErrCorruptCheckpoint error is reported when checksum does not match
+var ErrCorruptCheckpoint = fmt.Errorf("checkpoint is corrupted")
+
+// ErrCheckpointNotFound is reported when checkpoint is not found for a given key
+var ErrCheckpointNotFound = fmt.Errorf("checkpoint is not found")

pkg/kubelet/checkpointmanager/testing/util.go

@@ -27,10 +27,12 @@ type MemStore struct {
 	sync.Mutex
 }
 
+// NewMemStore returns an instance of MemStore
 func NewMemStore() *MemStore {
 	return &MemStore{mem: make(map[string][]byte)}
 }
 
+// Write writes the data to the store
 func (mstore *MemStore) Write(key string, data []byte) error {
 	mstore.Lock()
 	defer mstore.Unlock()
@@ -38,6 +40,7 @@ func (mstore *MemStore) Write(key string, data []byte) error {
 	return nil
 }
 
+// Read returns data read from store
 func (mstore *MemStore) Read(key string) ([]byte, error) {
 	mstore.Lock()
 	defer mstore.Unlock()
@@ -48,6 +51,7 @@ func (mstore *MemStore) Read(key string) ([]byte, error) {
 	return data, nil
 }
 
+// Delete deletes data from the store
 func (mstore *MemStore) Delete(key string) error {
 	mstore.Lock()
 	defer mstore.Unlock()
@@ -55,6 +59,7 @@ func (mstore *MemStore) Delete(key string) error {
 	return nil
 }
 
+// List returns all the keys from the store
 func (mstore *MemStore) List() ([]string, error) {
 	mstore.Lock()
 	defer mstore.Unlock()