cleanup: move pkg/ to internal/

The internal/ directory in Go has a special meaning, and indicates that
those packages are not meant for external consumption. Ceph-CSI does
provide public APIs for other projects to consume. There is no plan to
keep the API of the internally used packages stable.

Closes: #903
Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/util/k8scmcache.go

@@ -0,0 +1,188 @@
+/*
+Copyright 2018 The Ceph-CSI 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 util
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"regexp"
+
+	"github.com/pkg/errors"
+	v1 "k8s.io/api/core/v1"
+	apierrs "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	k8s "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/clientcmd"
+	"k8s.io/klog"
+)
+
+// K8sCMCache to store metadata
+type K8sCMCache struct {
+	Client    *k8s.Clientset
+	Namespace string
+}
+
+const (
+	defaultNamespace = "default"
+
+	cmLabel   = "csi-metadata"
+	cmDataKey = "content"
+
+	csiMetadataLabelAttr = "com.ceph.ceph-csi/metadata"
+)
+
+// GetK8sNamespace returns pod namespace. if pod namespace is empty
+// it returns default namespace
+func GetK8sNamespace() string {
+	namespace := os.Getenv("POD_NAMESPACE")
+	if namespace == "" {
+		return defaultNamespace
+	}
+	return namespace
+}
+
+// NewK8sClient create kubernetes client
+func NewK8sClient() *k8s.Clientset {
+	var cfg *rest.Config
+	var err error
+	cPath := os.Getenv("KUBERNETES_CONFIG_PATH")
+	if cPath != "" {
+		cfg, err = clientcmd.BuildConfigFromFlags("", cPath)
+		if err != nil {
+			klog.Errorf("Failed to get cluster config with error: %v\n", err)
+			os.Exit(1)
+		}
+	} else {
+		cfg, err = rest.InClusterConfig()
+		if err != nil {
+			klog.Errorf("Failed to get cluster config with error: %v\n", err)
+			os.Exit(1)
+		}
+	}
+	client, err := k8s.NewForConfig(cfg)
+	if err != nil {
+		klog.Errorf("Failed to create client with error: %v\n", err)
+		os.Exit(1)
+	}
+	return client
+}
+
+func (k8scm *K8sCMCache) getMetadataCM(resourceID string) (*v1.ConfigMap, error) {
+	cm, err := k8scm.Client.CoreV1().ConfigMaps(k8scm.Namespace).Get(context.TODO(), resourceID, metav1.GetOptions{})
+	if err != nil {
+		return nil, err
+	}
+	return cm, nil
+}
+
+// ForAll list the metadata in configmaps and filters outs based on the pattern
+func (k8scm *K8sCMCache) ForAll(pattern string, destObj interface{}, f ForAllFunc) error {
+	listOpts := metav1.ListOptions{LabelSelector: fmt.Sprintf("%s=%s", csiMetadataLabelAttr, cmLabel)}
+	cms, err := k8scm.Client.CoreV1().ConfigMaps(k8scm.Namespace).List(context.TODO(), listOpts)
+	if err != nil {
+		return errors.Wrap(err, "k8s-cm-cache: failed to list metadata configmaps")
+	}
+
+	for i := range cms.Items {
+		data := cms.Items[i].Data[cmDataKey]
+		match, err := regexp.MatchString(pattern, cms.Items[i].ObjectMeta.Name)
+		if err != nil {
+			continue
+		}
+		if !match {
+			continue
+		}
+		if err = json.Unmarshal([]byte(data), destObj); err != nil {
+			return errors.Wrapf(err, "k8s-cm-cache: JSON unmarshaling failed for configmap %s", cms.Items[i].ObjectMeta.Name)
+		}
+		if err = f(cms.Items[i].ObjectMeta.Name); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Create stores the metadata in configmaps with identifier name
+func (k8scm *K8sCMCache) Create(identifier string, data interface{}) error {
+	cm, err := k8scm.getMetadataCM(identifier)
+	if cm != nil && err == nil {
+		klog.V(4).Infof("k8s-cm-cache: configmap %s already exists, skipping configmap creation", identifier)
+		return nil
+	}
+	dataJSON, err := json.Marshal(data)
+	if err != nil {
+		return errors.Wrapf(err, "k8s-cm-cache: JSON marshaling failed for configmap %s", identifier)
+	}
+	cm = &v1.ConfigMap{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      identifier,
+			Namespace: k8scm.Namespace,
+			Labels: map[string]string{
+				csiMetadataLabelAttr: cmLabel,
+			},
+		},
+		Data: map[string]string{},
+	}
+	cm.Data[cmDataKey] = string(dataJSON)
+
+	_, err = k8scm.Client.CoreV1().ConfigMaps(k8scm.Namespace).Create(context.TODO(), cm, metav1.CreateOptions{})
+	if err != nil {
+		if apierrs.IsAlreadyExists(err) {
+			klog.V(4).Infof("k8s-cm-cache: configmap %s already exists", identifier)
+			return nil
+		}
+		return errors.Wrapf(err, "k8s-cm-cache: couldn't persist %s metadata as configmap", identifier)
+	}
+
+	klog.V(4).Infof("k8s-cm-cache: configmap %s successfully created", identifier)
+	return nil
+}
+
+// Get retrieves the metadata in configmaps with identifier name
+func (k8scm *K8sCMCache) Get(identifier string, data interface{}) error {
+	cm, err := k8scm.getMetadataCM(identifier)
+	if err != nil {
+		if apierrs.IsNotFound(err) {
+			return &CacheEntryNotFound{err}
+		}
+
+		return err
+	}
+	err = json.Unmarshal([]byte(cm.Data[cmDataKey]), data)
+	if err != nil {
+		return errors.Wrapf(err, "k8s-cm-cache: JSON unmarshaling failed for configmap %s", identifier)
+	}
+	return nil
+}
+
+// Delete deletes the metadata in configmaps with identifier name
+func (k8scm *K8sCMCache) Delete(identifier string) error {
+	err := k8scm.Client.CoreV1().ConfigMaps(k8scm.Namespace).Delete(context.TODO(), identifier, metav1.DeleteOptions{})
+	if err != nil {
+		if apierrs.IsNotFound(err) {
+			klog.V(4).Infof("k8s-cm-cache: cannot delete missing metadata configmap %s, assuming it's already deleted", identifier)
+			return nil
+		}
+
+		return errors.Wrapf(err, "k8s-cm-cache: couldn't delete metadata configmap %s", identifier)
+	}
+	klog.V(4).Infof("k8s-cm-cache: successfully deleted metadata configmap %s", identifier)
+	return nil
+}