[#340] Add notification configuration handlers

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

api/layer/notifications.go

@@ -0,0 +1,146 @@
+package layer
+
+import (
+	"bytes"
+	"context"
+	"encoding/xml"
+	"io"
+
+	"github.com/google/uuid"
+	"github.com/nspcc-dev/neofs-s3-gw/api/data"
+	"github.com/nspcc-dev/neofs-s3-gw/api/errors"
+	"go.uber.org/zap"
+)
+
+type (
+	PutBucketNotificationConfigurationParams struct {
+		BktInfo *data.BucketInfo
+		Reader  io.Reader
+	}
+)
+
+func (n *layer) PutBucketNotificationConfiguration(ctx context.Context, p *PutBucketNotificationConfigurationParams) error {
+	if !n.IsNotificationEnabled() {
+		return errors.GetAPIError(errors.ErrNotificationNotEnabled)
+	}
+
+	var (
+		buf       bytes.Buffer
+		tee       = io.TeeReader(p.Reader, &buf)
+		conf      = &data.NotificationConfiguration{}
+		completed bool
+		err       error
+	)
+
+	if err = xml.NewDecoder(tee).Decode(conf); err != nil {
+		return errors.GetAPIError(errors.ErrMalformedXML)
+	}
+
+	if completed, err = n.checkAndCompleteNotificationConfiguration(conf); err != nil {
+		return err
+	}
+	if completed {
+		confXML, err := xml.Marshal(conf)
+		if err != nil {
+			return err
+		}
+		buf.Reset()
+		buf.Write(confXML)
+	}
+
+	s := &PutSystemObjectParams{
+		BktInfo:  p.BktInfo,
+		ObjName:  p.BktInfo.NotificationConfigurationObjectName(),
+		Metadata: map[string]string{},
+		Prefix:   "",
+		Reader:   &buf,
+	}
+
+	obj, err := n.putSystemObjectIntoNeoFS(ctx, s)
+	if err != nil {
+		return err
+	}
+
+	if obj.Size == 0 && !conf.IsEmpty() {
+		return errors.GetAPIError(errors.ErrInternalError)
+	}
+
+	if err = n.systemCache.PutNotificationConfiguration(systemObjectKey(p.BktInfo, s.ObjName), conf); err != nil {
+		n.log.Error("couldn't cache system object", zap.Error(err))
+	}
+
+	return nil
+}
+
+func (n *layer) GetBucketNotificationConfiguration(ctx context.Context, bktInfo *data.BucketInfo) (*data.NotificationConfiguration, error) {
+	if !n.IsNotificationEnabled() {
+		return nil, errors.GetAPIError(errors.ErrNotificationNotEnabled)
+	}
+	conf, err := n.getNotificationConf(ctx, bktInfo, bktInfo.NotificationConfigurationObjectName())
+	if err != nil {
+		if errors.IsS3Error(err, errors.ErrNoSuchKey) {
+			return &data.NotificationConfiguration{}, nil
+		}
+		return nil, err
+	}
+
+	return conf, nil
+}
+
+func (n *layer) getNotificationConf(ctx context.Context, bkt *data.BucketInfo, sysName string) (*data.NotificationConfiguration, error) {
+	if conf := n.systemCache.GetNotificationConfiguration(systemObjectKey(bkt, sysName)); conf != nil {
+		return conf, nil
+	}
+
+	obj, err := n.getSystemObjectFromNeoFS(ctx, bkt, sysName)
+	if err != nil {
+		return nil, err
+	}
+
+	conf := &data.NotificationConfiguration{}
+
+	if err = xml.Unmarshal(obj.Payload(), &conf); err != nil {
+		return nil, err
+	}
+
+	if err = n.systemCache.PutNotificationConfiguration(systemObjectKey(bkt, sysName), conf); err != nil {
+		n.log.Warn("couldn't put system meta to objects cache",
+			zap.Stringer("object id", obj.ID()),
+			zap.Stringer("bucket id", bkt.CID),
+			zap.Error(err))
+	}
+
+	return conf, nil
+}
+
+func (n *layer) checkAndCompleteNotificationConfiguration(c *data.NotificationConfiguration) (completed bool, err error) {
+	if c == nil {
+		return
+	}
+
+	if c.TopicConfigurations != nil || c.LambdaFunctionConfigurations != nil {
+		return completed, errors.GetAPIError(errors.ErrNotificationTopicNotSupported)
+	}
+
+	for i, q := range c.QueueConfigurations {
+		if err = checkEvents(q.Events); err != nil {
+			return
+		}
+		if q.ID == "" {
+			completed = true
+			c.QueueConfigurations[i].ID = uuid.NewString()
+		}
+	}
+
+	return
+}
+
+func checkEvents(events []string) error {
+	for _, e := range events {
+		if _, ok := data.ValidEvents[e]; !ok {
+			return errors.GetAPIError(errors.ErrEventNotification)
+		}
+	}
+
+	return nil
+}