| // Copyright 2017 Google Inc. All Rights Reserved. |
| // |
| // 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 ( |
| "strings" |
| "time" |
| |
| vkit "cloud.google.com/go/pubsub/apiv1" |
| "golang.org/x/net/context" |
| ) |
| |
| // Snapshot is a reference to a PubSub snapshot. |
| type snapshot struct { |
| s service |
| |
| // 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{ |
| s: c.s, |
| name: vkit.SubscriberSnapshotPath(c.projectID, id), |
| } |
| } |
| |
| // Snapshots returns an iterator which returns snapshots for this project. |
| func (c *Client) snapshots(ctx context.Context) *snapshotConfigIterator { |
| return &snapshotConfigIterator{ |
| next: c.s.listProjectSnapshots(ctx, c.fullyQualifiedProjectName()), |
| } |
| } |
| |
| // SnapshotConfigIterator is an iterator that returns a series of snapshots. |
| type snapshotConfigIterator struct { |
| next nextSnapshotFunc |
| } |
| |
| // 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.s.deleteSnapshot(ctx, snap.name) |
| } |
| |
| // SeekTime 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 { |
| return s.s.seekToTime(ctx, s.name, t) |
| } |
| |
| // Snapshot 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 = vkit.SubscriberSnapshotPath(strings.Split(s.name, "/")[1], name) |
| } |
| return s.s.createSnapshot(ctx, name, s.name) |
| } |
| |
| // SeekSnapshot seeks the subscription to a snapshot. |
| // |
| // The snapshot needs not be created from this subscription, |
| // but the snapshot must be for the topic this subscription is subscribed to. |
| func (s *Subscription) seekToSnapshot(ctx context.Context, snap *snapshot) error { |
| return s.s.seekToSnapshot(ctx, s.name, snap.name) |
| } |