feat(zfs-localpv): initial commit

provisioning and deprovisioning of
the volumes on the node where zfs pool
has already been setup. Pool name and the volume
parameters has to be given in storage class
which will be used to provision the volume.

Signed-off-by: Pawan <pawan@mayadata.io>

pkg/builder/buildlist.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2019 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 builder
+
+import (
+	apis "github.com/openebs/zfs-localpv/pkg/apis/openebs.io/core/v1alpha1"
+)
+
+// ListBuilder enables building an instance of
+// ZFSVolumeList
+type ListBuilder struct {
+	list    *apis.ZFSVolumeList
+	filters predicateList
+}
+
+// NewListBuilder returns a new instance of ListBuilder
+func NewListBuilder() *ListBuilder {
+	return &ListBuilder{
+		list: &apis.ZFSVolumeList{},
+	}
+}
+
+// ListBuilderFrom returns a new instance of
+// ListBuilder from API list instance
+func ListBuilderFrom(vols apis.ZFSVolumeList) *ListBuilder {
+	b := &ListBuilder{list: &apis.ZFSVolumeList{}}
+	if len(vols.Items) == 0 {
+		return b
+	}
+
+	b.list.Items = append(b.list.Items, vols.Items...)
+	return b
+}
+
+// List returns the list of pod
+// instances that was built by this
+// builder
+func (b *ListBuilder) List() *apis.ZFSVolumeList {
+	if b.filters == nil || len(b.filters) == 0 {
+		return b.list
+	}
+
+	filtered := &apis.ZFSVolumeList{}
+	for _, vol := range b.list.Items {
+		vol := vol // pin it
+		if b.filters.all(From(&vol)) {
+			filtered.Items = append(filtered.Items, vol)
+		}
+	}
+	return filtered
+}
+
+// WithFilter add filters on which the pod
+// has to be filtered
+func (b *ListBuilder) WithFilter(pred ...Predicate) *ListBuilder {
+	b.filters = append(b.filters, pred...)
+	return b
+}