virtcontainers: Add a Store manager

Each virtcontainers module/component should be able to get a handler on
a Store for loading component specific items. The Store manager is an
internal Store layer for tracking all created Stores.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

virtcontainers/store/manager.go

@@ -7,6 +7,7 @@ package store
 
 import (
 	"context"
+	"fmt"
 	"net/url"
 	"sync"
 
@@ -87,6 +88,48 @@ type Store struct {
 	host   string
 }
 
+type manager struct {
+	sync.RWMutex
+	stores map[string]*Store
+}
+
+var stores = &manager{stores: make(map[string]*Store)}
+
+func (m *manager) addStore(s *Store) (err error) {
+	if s == nil {
+		return fmt.Errorf("Store can not be nil")
+	}
+
+	if s.url == "" {
+		return fmt.Errorf("Store URL can not be nil")
+	}
+
+	m.Lock()
+	defer m.Unlock()
+
+	if m.stores[s.url] != nil {
+		return fmt.Errorf("Store %s already added", s.url)
+	}
+
+	m.stores[s.url] = s
+
+	return nil
+}
+
+func (m *manager) removeStore(url string) {
+	m.Lock()
+	defer m.Unlock()
+
+	delete(m.stores, url)
+}
+
+func (m *manager) findStore(url string) *Store {
+	m.RLock()
+	defer m.RUnlock()
+
+	return m.stores[url]
+}
+
 // New will return a new virtcontainers Store.
 // If there is already a Store for the URL, we will re-use it.
 // Otherwise a new Store is created.

virtcontainers/store/manager_test.go

@@ -12,10 +12,75 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+var storeRoot = "file:///root1/"
+
 func TestNewStore(t *testing.T) {
-	s, err := New(context.Background(), "file:///root/")
+	s, err := New(context.Background(), storeRoot)
 	assert.Nil(t, err)
 	assert.Equal(t, s.scheme, "file")
 	assert.Equal(t, s.host, "")
-	assert.Equal(t, s.path, "/root/")
+	assert.Equal(t, s.path, "/root1/")
+}
+
+func TestManagerAddStore(t *testing.T) {
+	s, err := New(context.Background(), storeRoot)
+	assert.Nil(t, err)
+	err = stores.addStore(s)
+	defer stores.removeStore(storeRoot)
+	assert.Nil(t, err, "addStore failed")
+
+	// Duplicate, should fail
+	err = stores.addStore(s)
+	assert.NotNil(t, err, "addStore should have failed")
+
+	// Try with an empty URL
+	sEmpty, err := New(context.Background(), storeRoot)
+	assert.Nil(t, err)
+	sEmpty.url = ""
+	err = stores.addStore(sEmpty)
+	assert.NotNil(t, err, "addStore should have failed on an empty store URL")
+
+}
+
+func TestManagerRemoveStore(t *testing.T) {
+	s, err := New(context.Background(), storeRoot)
+	assert.Nil(t, err)
+
+	err = stores.addStore(s)
+	assert.Nil(t, err, "addStore failed")
+
+	// Positive find
+	newStore := stores.findStore(storeRoot)
+	assert.NotNil(t, newStore, "findStore failed")
+
+	// Negative removal
+	stores.removeStore(storeRoot + "foobar")
+
+	// We should still find storeRoot
+	newStore = stores.findStore(storeRoot)
+	assert.NotNil(t, newStore, "findStore failed")
+
+	// Positive removal
+	stores.removeStore(storeRoot)
+
+	// We should no longer find storeRoot
+	newStore = stores.findStore(storeRoot)
+	assert.Nil(t, newStore, "findStore should not have found %s", storeRoot)
+}
+
+func TestManagerFindStore(t *testing.T) {
+	s, err := New(context.Background(), storeRoot)
+	assert.Nil(t, err)
+
+	err = stores.addStore(s)
+	defer stores.removeStore(storeRoot)
+	assert.Nil(t, err, "addStore failed")
+
+	// Positive find
+	newStore := stores.findStore(storeRoot)
+	assert.NotNil(t, newStore, "findStore failed")
+
+	// Negative find
+	newStore = stores.findStore(storeRoot + "foobar")
+	assert.Nil(t, newStore, "findStore should not have found a new store")
 }