lib: sandbox: refactor to memory store

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

lib/container_server.go

@@ -168,7 +168,7 @@ func New(config *Config) (*ContainerServer, error) {
 		state: &containerServerState{
 			containers:      oci.NewMemoryStore(),
 			infraContainers: oci.NewMemoryStore(),
-			sandboxes:       make(map[string]*sandbox.Sandbox),
+			sandboxes:       sandbox.NewMemoryStore(),
 			processLevels:   make(map[string]int),
 		},
 		config: config,
@@ -617,7 +617,7 @@ func (c *ContainerServer) Shutdown() error {
 type containerServerState struct {
 	containers      oci.ContainerStorer
 	infraContainers oci.ContainerStorer
-	sandboxes       map[string]*sandbox.Sandbox
+	sandboxes       sandbox.Storer
 	// processLevels The number of sandboxes using the same SELinux MCS level. Need to release MCS Level, when count reaches 0
 	processLevels map[string]int
 }
@@ -626,7 +626,7 @@ type containerServerState struct {
 func (c *ContainerServer) AddContainer(ctr *oci.Container) {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	sandbox := c.state.sandboxes[ctr.Sandbox()]
+	sandbox := c.state.sandboxes.Get(ctr.Sandbox())
 	sandbox.AddContainer(ctr)
 	c.state.containers.Add(ctr.ID(), ctr)
 }
@@ -665,7 +665,7 @@ func (c *ContainerServer) RemoveContainer(ctr *oci.Container) {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
 	sbID := ctr.Sandbox()
-	sb := c.state.sandboxes[sbID]
+	sb := c.state.sandboxes.Get(sbID)
 	sb.RemoveContainer(ctr)
 	c.state.containers.Delete(ctr.ID())
 }
@@ -706,7 +706,7 @@ func (c *ContainerServer) ListContainers(filters ...func(*oci.Container) bool) (
 func (c *ContainerServer) AddSandbox(sb *sandbox.Sandbox) {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	c.state.sandboxes[sb.ID()] = sb
+	c.state.sandboxes.Add(sb.ID(), sb)
 	c.state.processLevels[selinux.NewContext(sb.ProcessLabel())["level"]]++
 }
 
@@ -714,17 +714,14 @@ func (c *ContainerServer) AddSandbox(sb *sandbox.Sandbox) {
 func (c *ContainerServer) GetSandbox(id string) *sandbox.Sandbox {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	return c.state.sandboxes[id]
+	return c.state.sandboxes.Get(id)
 }
 
 // GetSandboxContainer returns a sandbox's infra container
 func (c *ContainerServer) GetSandboxContainer(id string) *oci.Container {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	sb, ok := c.state.sandboxes[id]
-	if !ok {
-		return nil
-	}
+	sb := c.state.sandboxes.Get(id)
 	return sb.InfraContainer()
 }
 
@@ -732,21 +729,25 @@ func (c *ContainerServer) GetSandboxContainer(id string) *oci.Container {
 func (c *ContainerServer) HasSandbox(id string) bool {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	_, ok := c.state.sandboxes[id]
-	return ok
+	sb := c.state.sandboxes.Get(id)
+	return sb != nil
 }
 
 // RemoveSandbox removes a sandbox from the state store
 func (c *ContainerServer) RemoveSandbox(id string) {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	processLabel := c.state.sandboxes[id].ProcessLabel()
-	delete(c.state.sandboxes, id)
+	sb := c.state.sandboxes.Get(id)
+	processLabel := sb.ProcessLabel()
+	c.state.sandboxes.Delete(id)
 	level := selinux.NewContext(processLabel)["level"]
-	c.state.processLevels[level]--
-	if c.state.processLevels[level] == 0 {
-		label.ReleaseLabel(processLabel)
-		delete(c.state.processLevels, level)
+	pl, ok := c.state.processLevels[level]
+	if ok {
+		c.state.processLevels[level] = pl - 1
+		if c.state.processLevels[level] == 0 {
+			label.ReleaseLabel(processLabel)
+			delete(c.state.processLevels, level)
+		}
 	}
 }
 
@@ -754,12 +755,7 @@ func (c *ContainerServer) RemoveSandbox(id string) {
 func (c *ContainerServer) ListSandboxes() []*sandbox.Sandbox {
 	c.stateLock.Lock()
 	defer c.stateLock.Unlock()
-	sbArray := make([]*sandbox.Sandbox, 0, len(c.state.sandboxes))
-	for _, sb := range c.state.sandboxes {
-		sbArray = append(sbArray, sb)
-	}
-
-	return sbArray
+	return c.state.sandboxes.List()
 }
 
 // LibcontainerStats gets the stats for the container with the given id from runc/libcontainer

lib/sandbox/history.go

@@ -0,0 +1,31 @@
+package sandbox
+
+import "sort"
+
+// History is a convenience type for storing a list of sandboxes,
+// sorted by creation date in descendant order.
+type History []*Sandbox
+
+// Len returns the number of sandboxes in the history.
+func (history *History) Len() int {
+	return len(*history)
+}
+
+// Less compares two sandboxes and returns true if the second one
+// was created before the first one.
+func (history *History) Less(i, j int) bool {
+	sandboxes := *history
+	// FIXME: state access should be serialized
+	return sandboxes[j].created.Before(sandboxes[i].created)
+}
+
+// Swap switches sandboxes i and j positions in the history.
+func (history *History) Swap(i, j int) {
+	sandboxes := *history
+	sandboxes[i], sandboxes[j] = sandboxes[j], sandboxes[i]
+}
+
+// sort orders the history by creation date in descendant order.
+func (history *History) sort() {
+	sort.Sort(history)
+}

lib/sandbox/memory_store.go

@@ -0,0 +1,92 @@
+package sandbox
+
+import "sync"
+
+// memoryStore implements a Store in memory.
+type memoryStore struct {
+	s map[string]*Sandbox
+	sync.RWMutex
+}
+
+// NewMemoryStore initializes a new memory store.
+func NewMemoryStore() Storer {
+	return &memoryStore{
+		s: make(map[string]*Sandbox),
+	}
+}
+
+// Add appends a new sandbox to the memory store.
+// It overrides the id if it existed before.
+func (c *memoryStore) Add(id string, cont *Sandbox) {
+	c.Lock()
+	c.s[id] = cont
+	c.Unlock()
+}
+
+// Get returns a sandbox from the store by id.
+func (c *memoryStore) Get(id string) *Sandbox {
+	c.RLock()
+	res := c.s[id]
+	c.RUnlock()
+	return res
+}
+
+// Delete removes a sandbox from the store by id.
+func (c *memoryStore) Delete(id string) {
+	c.Lock()
+	delete(c.s, id)
+	c.Unlock()
+}
+
+// List returns a sorted list of sandboxes from the store.
+// The sandboxes are ordered by creation date.
+func (c *memoryStore) List() []*Sandbox {
+	sandboxes := History(c.all())
+	sandboxes.sort()
+	return sandboxes
+}
+
+// Size returns the number of sandboxes in the store.
+func (c *memoryStore) Size() int {
+	c.RLock()
+	defer c.RUnlock()
+	return len(c.s)
+}
+
+// First returns the first sandbox found in the store by a given filter.
+func (c *memoryStore) First(filter StoreFilter) *Sandbox {
+	for _, cont := range c.all() {
+		if filter(cont) {
+			return cont
+		}
+	}
+	return nil
+}
+
+// ApplyAll calls the reducer function with every sandbox in the store.
+// This operation is asynchronous in the memory store.
+// NOTE: Modifications to the store MUST NOT be done by the StoreReducer.
+func (c *memoryStore) ApplyAll(apply StoreReducer) {
+	wg := new(sync.WaitGroup)
+	for _, cont := range c.all() {
+		wg.Add(1)
+		go func(sandbox *Sandbox) {
+			apply(sandbox)
+			wg.Done()
+		}(cont)
+	}
+
+	wg.Wait()
+}
+
+func (c *memoryStore) all() []*Sandbox {
+	c.RLock()
+	sandboxes := make([]*Sandbox, 0, len(c.s))
+	for _, cont := range c.s {
+		sandboxes = append(sandboxes, cont)
+	}
+	c.RUnlock()
+	return sandboxes
+}
+
+var _ Storer = &memoryStore{}

lib/sandbox/sandbox.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 
 	"github.com/containernetworking/plugins/pkg/ns"
 	"github.com/docker/docker/pkg/mount"
@@ -158,6 +159,7 @@ type Sandbox struct {
 	// ipv4 or ipv6 cache
 	ip                 string
 	seccompProfilePath string
+	created            time.Time
 }
 
 const (
@@ -202,6 +204,7 @@ func New(id, namespace, name, kubeName, logDir string, labels, annotations map[s
 	sb.resolvPath = resolvPath
 	sb.hostname = hostname
 	sb.portMappings = portMappings
+	sb.created = time.Now()
 
 	return sb, nil
 }

lib/sandbox/store.go

@@ -0,0 +1,27 @@
+package sandbox
+
+// StoreFilter defines a function to filter
+// sandboxes in the store.
+type StoreFilter func(*Sandbox) bool
+
+// StoreReducer defines a function to
+// manipulate sandboxes in the store
+type StoreReducer func(*Sandbox)
+
+// Storer defines an interface that any container store must implement.
+type Storer interface {
+	// Add appends a new sandbox to the store.
+	Add(string, *Sandbox)
+	// Get returns a sandbox from the store by the identifier it was stored with.
+	Get(string) *Sandbox
+	// Delete removes a sandbox from the store by the identifier it was stored with.
+	Delete(string)
+	// List returns a list of sandboxes from the store.
+	List() []*Sandbox
+	// Size returns the number of sandboxes in the store.
+	Size() int
+	// First returns the first sandbox found in the store by a given filter.
+	First(StoreFilter) *Sandbox
+	// ApplyAll calls the reducer function with every sandbox in the store.
+	ApplyAll(StoreReducer)
+}