Add Snapshot Controller

This PR adds external snapshot controller and main package under cmd.

pkg/controller/csi_handler.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2018 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 controller
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/container-storage-interface/spec/lib/go/csi/v0"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/pkg/apis/volumesnapshot/v1alpha1"
+	"github.com/kubernetes-csi/external-snapshotter/pkg/connection"
+	"k8s.io/api/core/v1"
+)
+
+// Handler is responsible for handling VolumeSnapshot events from informer.
+type Handler interface {
+	CreateSnapshot(snapshot *crdv1.VolumeSnapshot, volume *v1.PersistentVolume, parameters map[string]string) (string, string, int64, *csi.SnapshotStatus, error)
+	DeleteSnapshot(content *crdv1.VolumeSnapshotContent) error
+	GetSnapshotStatus(content *crdv1.VolumeSnapshotContent) (*csi.SnapshotStatus, int64, error)
+}
+
+// csiHandler is a handler that calls CSI to create/delete volume snapshot.
+type csiHandler struct {
+	csiConnection          connection.CSIConnection
+	timeout                time.Duration
+	snapshotNamePrefix     string
+	snapshotNameUUIDLength int
+}
+
+func NewCSIHandler(
+	csiConnection connection.CSIConnection,
+	timeout time.Duration,
+	snapshotNamePrefix string,
+	snapshotNameUUIDLength int,
+) Handler {
+	return &csiHandler{
+		csiConnection:          csiConnection,
+		timeout:                timeout,
+		snapshotNamePrefix:     snapshotNamePrefix,
+		snapshotNameUUIDLength: snapshotNameUUIDLength,
+	}
+}
+
+func (handler *csiHandler) CreateSnapshot(snapshot *crdv1.VolumeSnapshot, volume *v1.PersistentVolume, parameters map[string]string) (string, string, int64, *csi.SnapshotStatus, error) {
+
+	ctx, cancel := context.WithTimeout(context.Background(), handler.timeout)
+	defer cancel()
+
+	snapshotName, err := makeSnapshotName(handler.snapshotNamePrefix, string(snapshot.UID), handler.snapshotNameUUIDLength)
+	if err != nil {
+		return "", "", 0, nil, err
+	}
+	return handler.csiConnection.CreateSnapshot(ctx, snapshotName, snapshot, volume, parameters)
+}
+
+func (handler *csiHandler) DeleteSnapshot(content *crdv1.VolumeSnapshotContent) error {
+	if content.Spec.CSI == nil {
+		return fmt.Errorf("CSISnapshot not defined in spec")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), handler.timeout)
+	defer cancel()
+
+	err := handler.csiConnection.DeleteSnapshot(ctx, content.Spec.CSI.SnapshotHandle)
+	if err != nil {
+		return fmt.Errorf("failed to delete snapshot data %s: %q", content.Name, err)
+	}
+
+	return nil
+}
+
+func (handler *csiHandler) GetSnapshotStatus(content *crdv1.VolumeSnapshotContent) (*csi.SnapshotStatus, int64, error) {
+	if content.Spec.CSI == nil {
+		return nil, 0, fmt.Errorf("CSISnapshot not defined in spec")
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), handler.timeout)
+	defer cancel()
+
+	csiSnapshotStatus, timestamp, err := handler.csiConnection.GetSnapshotStatus(ctx, content.Spec.CSI.SnapshotHandle)
+	if err != nil {
+		return nil, 0, fmt.Errorf("failed to list snapshot data %s: %q", content.Name, err)
+	}
+	return csiSnapshotStatus, timestamp, nil
+}
+
+func makeSnapshotName(prefix, snapshotUID string, snapshotNameUUIDLength int) (string, error) {
+	// create persistent name based on a volumeNamePrefix and volumeNameUUIDLength
+	// of PVC's UID
+	if len(prefix) == 0 {
+		return "", fmt.Errorf("Snapshot name prefix cannot be of length 0")
+	}
+	if len(snapshotUID) == 0 {
+		return "", fmt.Errorf("Corrupted snapshot object, it is missing UID")
+	}
+	if snapshotNameUUIDLength == -1 {
+		// Default behavior is to not truncate or remove dashes
+		return fmt.Sprintf("%s-%s", prefix, snapshotUID), nil
+	}
+	return fmt.Sprintf("%s-%s", prefix, strings.Replace(snapshotUID, "-", "", -1)[0:snapshotNameUUIDLength]), nil
+}