Implement DriversStore as a struct

This allows us to hide
- the mutex handling
- the initialization
as implementation details.

Signed-off-by: Maria Ntalla <mntalla@pivotal.io>

pkg/volume/csi/BUILD

@@ -6,6 +6,7 @@ go_library(
         "csi_attacher.go",
         "csi_block.go",
         "csi_client.go",
+        "csi_drivers_store.go",
         "csi_mounter.go",
         "csi_plugin.go",
         "csi_util.go",
@@ -44,6 +45,7 @@ go_test(
         "csi_attacher_test.go",
         "csi_block_test.go",
         "csi_client_test.go",
+        "csi_drivers_store_test.go",
         "csi_mounter_test.go",
         "csi_plugin_test.go",
     ],

pkg/volume/csi/csi_drivers_store.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package csi
+
+import (
+	"sync"
+
+	utilversion "k8s.io/apimachinery/pkg/util/version"
+)
+
+// Driver is a description of a CSI Driver, defined by an enpoint and the
+// highest CSI version supported
+type Driver struct {
+	endpoint                string
+	highestSupportedVersion *utilversion.Version
+}
+
+// DriversStore holds a list of CSI Drivers
+type DriversStore struct {
+	store
+	sync.RWMutex
+}
+
+type store map[string]Driver
+
+// Get lets you retrieve a CSI Driver by name.
+// This method is protected by a mutex.
+func (s *DriversStore) Get(driverName string) (Driver, bool) {
+	s.RLock()
+	defer s.RUnlock()
+
+	driver, ok := s.store[driverName]
+	return driver, ok
+}
+
+// Set lets you save a CSI Driver to the list and give it a specific name.
+// This method is protected by a mutex.
+func (s *DriversStore) Set(driverName string, driver Driver) {
+	s.Lock()
+	defer s.Unlock()
+
+	if s.store == nil {
+		s.store = store{}
+	}
+
+	s.store[driverName] = driver
+}
+
+// Delete lets you delete a CSI Driver by name.
+// This method is protected by a mutex.
+func (s *DriversStore) Delete(driverName string) {
+	s.Lock()
+	defer s.Unlock()
+
+	delete(s.store, driverName)
+}
+
+// Clear deletes all entries in the store.
+// This methiod is protected by a mutex.
+func (s *DriversStore) Clear() {
+	s.Lock()
+	defer s.Unlock()
+
+	s.store = store{}
+}

pkg/volume/csi/csi_drivers_store_test.go

@@ -0,0 +1,64 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package csi_test
+
+import (
+	"reflect"
+	"testing"
+
+	"k8s.io/kubernetes/pkg/volume/csi"
+)
+
+func TestDriversStore(t *testing.T) {
+	store := &csi.DriversStore{}
+	someDriver := csi.Driver{}
+
+	expectAbsent(t, store, "does-not-exist")
+
+	store.Set("some-driver", someDriver)
+	expectPresent(t, store, "some-driver", someDriver)
+
+	store.Delete("some-driver")
+	expectAbsent(t, store, "some-driver")
+
+	store.Set("some-driver", someDriver)
+
+	store.Clear()
+	expectAbsent(t, store, "some-driver")
+}
+
+func expectPresent(t *testing.T, store *csi.DriversStore, name string, expected csi.Driver) {
+	t.Helper()
+
+	retrieved, ok := store.Get(name)
+
+	if !ok {
+		t.Fatalf("expected driver '%s' to exist", name)
+	}
+
+	if !reflect.DeepEqual(retrieved, expected) {
+		t.Fatalf("expected driver '%s' to be equal to %v", name, expected)
+	}
+}
+
+func expectAbsent(t *testing.T, store *csi.DriversStore, name string) {
+	t.Helper()
+
+	if _, ok := store.Get(name); ok {
+		t.Fatalf("expected driver '%s' not to exist in store", name)
+	}
+}