refact(csi): use common lib-csi imports (#263)

Signed-off-by: shubham <shubham.bajpai@mayadata.io>

vendor/github.com/openebs/lib-csi/pkg/client/k8s/node.go

@@ -0,0 +1,101 @@
+/*
+Copyright 2020 The OpenEBS 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 k8s
+
+import (
+	"github.com/pkg/errors"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+// NodeGetter abstracts fetching of Node details from kubernetes cluster
+type NodeGetter interface {
+	Get(name string, options metav1.GetOptions) (*corev1.Node, error)
+}
+
+// NodeLister abstracts fetching of Nodes from kubernetes cluster
+type NodeLister interface {
+	List(options metav1.ListOptions) (*corev1.NodeList, error)
+}
+
+//NodeStruct returns a struct used to instantiate a kubernetes Node
+type NodeStruct struct{}
+
+// Node returnd a pointer to the node struct
+func Node() *NodeStruct {
+	return &NodeStruct{}
+}
+
+// Get returns a node instance from kubernetes cluster
+func (n *NodeStruct) Get(name string, options metav1.GetOptions) (*corev1.Node, error) {
+	cs, err := Clientset().Get()
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get node: %s", name)
+	}
+	return cs.CoreV1().Nodes().Get(name, options)
+}
+
+// List returns a slice of Nodes registered in a Kubernetes cluster
+func (n *NodeStruct) List(options metav1.ListOptions) (*corev1.NodeList, error) {
+	cs, err := Clientset().Get()
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get nodes")
+	}
+	return cs.CoreV1().Nodes().List(options)
+}
+
+// NumberOfNodes returns the number of nodes registered in a Kubernetes cluster
+func NumberOfNodes() (int, error) {
+	n := Node()
+	nodes, err := n.List(metav1.ListOptions{})
+	if err != nil {
+		return 0, errors.Wrapf(err, "failed to get the number of nodes")
+	}
+	return len(nodes.Items), nil
+}
+
+// GetNode returns a node instance from kubernetes cluster
+func GetNode(name string) (*corev1.Node, error) {
+	n := Node()
+	node, err := n.Get(name, metav1.GetOptions{})
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get node")
+	}
+	return node, nil
+}
+
+// ListNodes returns list of node instance from kubernetes cluster
+func ListNodes(options metav1.ListOptions) (*corev1.NodeList, error) {
+	n := Node()
+	nodelist, err := n.List(options)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to list node")
+	}
+	return nodelist, nil
+}
+
+// GetOSAndKernelVersion gets us the OS,Kernel version
+func GetOSAndKernelVersion() (string, error) {
+	nodes := Node()
+	// get a single node
+	firstNode, err := nodes.List(metav1.ListOptions{Limit: 1})
+	if err != nil {
+		return "unknown, unknown", errors.Wrapf(err, "failed to get the os kernel/arch")
+	}
+	nodedetails := firstNode.Items[0].Status.NodeInfo
+	return nodedetails.OSImage + ", " + nodedetails.KernelVersion, nil
+}