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- // Copyright 2017 Google LLC
- //
- // 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 pubsub
-
- import (
- "fmt"
- "strings"
- "time"
-
- "github.com/golang/protobuf/ptypes"
- "golang.org/x/net/context"
- pb "google.golang.org/genproto/googleapis/pubsub/v1"
- )
-
- // Snapshot is a reference to a PubSub snapshot.
- type Snapshot struct {
- c *Client
-
- // The fully qualified identifier for the snapshot, in the format "projects/<projid>/snapshots/<snap>"
- name string
- }
-
- // ID returns the unique identifier of the snapshot within its project.
- func (s *Snapshot) ID() string {
- slash := strings.LastIndex(s.name, "/")
- if slash == -1 {
- // name is not a fully-qualified name.
- panic("bad snapshot name")
- }
- return s.name[slash+1:]
- }
-
- // SnapshotConfig contains the details of a Snapshot.
- type SnapshotConfig struct {
- *Snapshot
- Topic *Topic
- Expiration time.Time
- }
-
- // Snapshot creates a reference to a snapshot.
- func (c *Client) Snapshot(id string) *Snapshot {
- return &Snapshot{
- c: c,
- name: fmt.Sprintf("projects/%s/snapshots/%s", c.projectID, id),
- }
- }
-
- // Snapshots returns an iterator which returns snapshots for this project.
- func (c *Client) Snapshots(ctx context.Context) *SnapshotConfigIterator {
- it := c.subc.ListSnapshots(ctx, &pb.ListSnapshotsRequest{
- Project: c.fullyQualifiedProjectName(),
- })
- next := func() (*SnapshotConfig, error) {
- snap, err := it.Next()
- if err != nil {
- return nil, err
- }
- return toSnapshotConfig(snap, c)
- }
- return &SnapshotConfigIterator{next: next}
- }
-
- // SnapshotConfigIterator is an iterator that returns a series of snapshots.
- type SnapshotConfigIterator struct {
- next func() (*SnapshotConfig, error)
- }
-
- // Next returns the next SnapshotConfig. Its second return value is iterator.Done if there are no more results.
- // Once Next returns iterator.Done, all subsequent calls will return iterator.Done.
- func (snaps *SnapshotConfigIterator) Next() (*SnapshotConfig, error) {
- return snaps.next()
- }
-
- // Delete deletes a snapshot.
- func (snap *Snapshot) Delete(ctx context.Context) error {
- return snap.c.subc.DeleteSnapshot(ctx, &pb.DeleteSnapshotRequest{Snapshot: snap.name})
- }
-
- // SeekToTime seeks the subscription to a point in time.
- //
- // Messages retained in the subscription that were published before this
- // time are marked as acknowledged, and messages retained in the
- // subscription that were published after this time are marked as
- // unacknowledged. Note that this operation affects only those messages
- // retained in the subscription (configured by SnapshotConfig). For example,
- // if `time` corresponds to a point before the message retention
- // window (or to a point before the system's notion of the subscription
- // creation time), only retained messages will be marked as unacknowledged,
- // and already-expunged messages will not be restored.
- func (s *Subscription) SeekToTime(ctx context.Context, t time.Time) error {
- ts, err := ptypes.TimestampProto(t)
- if err != nil {
- return err
- }
- _, err = s.c.subc.Seek(ctx, &pb.SeekRequest{
- Subscription: s.name,
- Target: &pb.SeekRequest_Time{ts},
- })
- return err
- }
-
- // CreateSnapshot creates a new snapshot from this subscription.
- // The snapshot will be for the topic this subscription is subscribed to.
- // If the name is empty string, a unique name is assigned.
- //
- // The created snapshot is guaranteed to retain:
- // (a) The existing backlog on the subscription. More precisely, this is
- // defined as the messages in the subscription's backlog that are
- // unacknowledged when Snapshot returns without error.
- // (b) Any messages published to the subscription's topic following
- // Snapshot returning without error.
- func (s *Subscription) CreateSnapshot(ctx context.Context, name string) (*SnapshotConfig, error) {
- if name != "" {
- name = fmt.Sprintf("projects/%s/snapshots/%s", strings.Split(s.name, "/")[1], name)
- }
- snap, err := s.c.subc.CreateSnapshot(ctx, &pb.CreateSnapshotRequest{
- Name: name,
- Subscription: s.name,
- })
- if err != nil {
- return nil, err
- }
- return toSnapshotConfig(snap, s.c)
- }
-
- // SeekToSnapshot seeks the subscription to a snapshot.
- //
- // The snapshot need not be created from this subscription,
- // but it must be for the topic this subscription is subscribed to.
- func (s *Subscription) SeekToSnapshot(ctx context.Context, snap *Snapshot) error {
- _, err := s.c.subc.Seek(ctx, &pb.SeekRequest{
- Subscription: s.name,
- Target: &pb.SeekRequest_Snapshot{snap.name},
- })
- return err
- }
-
- func toSnapshotConfig(snap *pb.Snapshot, c *Client) (*SnapshotConfig, error) {
- exp, err := ptypes.Timestamp(snap.ExpireTime)
- if err != nil {
- return nil, err
- }
- return &SnapshotConfig{
- Snapshot: &Snapshot{c: c, name: snap.Name},
- Topic: newTopic(c, snap.Topic),
- Expiration: exp,
- }, nil
- }
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