/
assigner.go
186 lines (159 loc) · 5.3 KB
/
assigner.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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
// Copyright 2020 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
//
// https://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
package wire
import (
"context"
"errors"
"fmt"
"reflect"
"sort"
"github.com/google/uuid"
"google.golang.org/grpc"
vkit "cloud.google.com/go/pubsublite/apiv1"
pb "google.golang.org/genproto/googleapis/cloud/pubsublite/v1"
)
// PartitionSet is a set of partition numbers.
type PartitionSet map[int]struct{}
// NewPartitionSet creates a partition set initialized from the given partition
// numbers.
func NewPartitionSet(partitions []int) PartitionSet {
var void struct{}
partitionSet := make(map[int]struct{})
for _, p := range partitions {
partitionSet[p] = void
}
return partitionSet
}
func newPartitionSet(assignmentpb *pb.PartitionAssignment) PartitionSet {
var partitions []int
for _, p := range assignmentpb.GetPartitions() {
partitions = append(partitions, int(p))
}
return NewPartitionSet(partitions)
}
// Ints returns the partitions contained in this set as an unsorted slice.
func (ps PartitionSet) Ints() (partitions []int) {
for p := range ps {
partitions = append(partitions, p)
}
return
}
// SortedInts returns the partitions contained in this set as a sorted slice.
func (ps PartitionSet) SortedInts() (partitions []int) {
partitions = ps.Ints()
sort.Ints(partitions)
return
}
// Contains returns true if this set contains the specified partition.
func (ps PartitionSet) Contains(partition int) bool {
_, exists := ps[partition]
return exists
}
// A function that generates a 16-byte UUID.
type generateUUIDFunc func() (uuid.UUID, error)
// partitionAssignmentReceiver must enact the received partition assignment from
// the server, or otherwise return an error, which will break the stream.
type partitionAssignmentReceiver func(PartitionSet) error
// assigner wraps the partition assignment stream and notifies a receiver when
// the server sends a new set of partition assignments for a subscriber.
type assigner struct {
// Immutable after creation.
assignmentClient *vkit.PartitionAssignmentClient
subscription string
initialReq *pb.PartitionAssignmentRequest
receiveAssignment partitionAssignmentReceiver
metadata pubsubMetadata
// Fields below must be guarded with mu.
stream *retryableStream
abstractService
}
func newAssigner(ctx context.Context, assignmentClient *vkit.PartitionAssignmentClient, genUUID generateUUIDFunc, settings ReceiveSettings, subscriptionPath string, receiver partitionAssignmentReceiver) (*assigner, error) {
clientID, err := genUUID()
if err != nil {
return nil, fmt.Errorf("pubsublite: failed to generate client UUID: %v", err)
}
a := &assigner{
assignmentClient: assignmentClient,
subscription: subscriptionPath,
initialReq: &pb.PartitionAssignmentRequest{
Request: &pb.PartitionAssignmentRequest_Initial{
Initial: &pb.InitialPartitionAssignmentRequest{
Subscription: subscriptionPath,
ClientId: clientID[:],
},
},
},
receiveAssignment: receiver,
metadata: newPubsubMetadata(),
}
a.stream = newRetryableStream(ctx, a, settings.Timeout, reflect.TypeOf(pb.PartitionAssignment{}))
a.metadata.AddClientInfo(settings.Framework)
return a, nil
}
func (a *assigner) Start() {
a.mu.Lock()
defer a.mu.Unlock()
if a.unsafeUpdateStatus(serviceStarting, nil) {
a.stream.Start()
}
}
func (a *assigner) Stop() {
a.mu.Lock()
defer a.mu.Unlock()
a.unsafeInitiateShutdown(serviceTerminating, nil)
}
func (a *assigner) newStream(ctx context.Context) (grpc.ClientStream, error) {
return a.assignmentClient.AssignPartitions(a.metadata.AddToContext(ctx))
}
func (a *assigner) initialRequest() (interface{}, initialResponseRequired) {
return a.initialReq, initialResponseRequired(false)
}
func (a *assigner) validateInitialResponse(_ interface{}) error {
// Should not be called as initialResponseRequired=false above.
return errors.New("pubsublite: unexpected initial response")
}
func (a *assigner) onStreamStatusChange(status streamStatus) {
a.mu.Lock()
defer a.mu.Unlock()
switch status {
case streamConnected:
a.unsafeUpdateStatus(serviceActive, nil)
case streamTerminated:
a.unsafeInitiateShutdown(serviceTerminated, a.stream.Error())
}
}
func (a *assigner) onResponse(response interface{}) {
assignment, _ := response.(*pb.PartitionAssignment)
err := a.receiveAssignment(newPartitionSet(assignment))
a.mu.Lock()
defer a.mu.Unlock()
if a.status >= serviceTerminating {
return
}
if err != nil {
a.unsafeInitiateShutdown(serviceTerminated, err)
return
}
a.stream.Send(&pb.PartitionAssignmentRequest{
Request: &pb.PartitionAssignmentRequest_Ack{
Ack: &pb.PartitionAssignmentAck{},
},
})
}
func (a *assigner) unsafeInitiateShutdown(targetStatus serviceStatus, err error) {
if !a.unsafeUpdateStatus(targetStatus, wrapError("assigner", a.subscription, err)) {
return
}
// No data to send. Immediately terminate the stream.
a.stream.Stop()
}