-
Notifications
You must be signed in to change notification settings - Fork 1.2k
/
snapshot.go
154 lines (138 loc) · 5.08 KB
/
snapshot.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
// 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 (
"context"
"fmt"
"strings"
"time"
pb "google.golang.org/genproto/googleapis/pubsub/v1"
"google.golang.org/protobuf/types/known/timestamppb"
)
// 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 (s *Snapshot) Delete(ctx context.Context) error {
return s.c.subc.DeleteSnapshot(ctx, &pb.DeleteSnapshotRequest{Snapshot: s.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 := timestamppb.New(t)
_, err := s.c.subc.Seek(ctx, &pb.SeekRequest{
Subscription: s.name,
Target: &pb.SeekRequest_Time{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{Snapshot: snap.name},
})
return err
}
func toSnapshotConfig(snap *pb.Snapshot, c *Client) (*SnapshotConfig, error) {
exp := snap.ExpireTime.AsTime()
return &SnapshotConfig{
Snapshot: &Snapshot{c: c, name: snap.Name},
Topic: newTopic(c, snap.Topic),
Expiration: exp,
}, nil
}