forked from uber/cadence
-
Notifications
You must be signed in to change notification settings - Fork 0
/
rpServiceResolver.go
238 lines (202 loc) · 6.51 KB
/
rpServiceResolver.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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package membership
import (
"sync"
"time"
"github.com/uber/cadence/common"
"github.com/dgryski/go-farm"
"github.com/uber-common/bark"
"github.com/uber/ringpop-go"
"github.com/uber/ringpop-go/events"
"github.com/uber/ringpop-go/hashring"
"github.com/uber/ringpop-go/swim"
)
const (
// RoleKey label is set by every single service as soon as it bootstraps its
// ringpop instance. The data for this key is the service name
RoleKey = "serviceName"
defaultRefreshInterval = time.Second * 10
replicaPoints = 100
)
type ringpopServiceResolver struct {
service string
isStarted bool
isStopped bool
rp *ringpop.Ringpop
shutdownCh chan struct{}
shutdownWG sync.WaitGroup
logger bark.Logger
ringLock sync.RWMutex
ring *hashring.HashRing
listenerLock sync.RWMutex
listeners map[string]chan<- *ChangedEvent
}
var _ ServiceResolver = (*ringpopServiceResolver)(nil)
func newRingpopServiceResolver(service string, rp *ringpop.Ringpop, logger bark.Logger) *ringpopServiceResolver {
return &ringpopServiceResolver{
service: service,
rp: rp,
logger: logger.WithFields(bark.Fields{"component": "ServiceResolver", RoleKey: service}),
ring: hashring.New(farm.Fingerprint32, replicaPoints),
listeners: make(map[string]chan<- *ChangedEvent),
shutdownCh: make(chan struct{}),
}
}
// Start starts the oracle
func (r *ringpopServiceResolver) Start() error {
r.ringLock.Lock()
defer r.ringLock.Unlock()
if r.isStarted {
return nil
}
r.rp.AddListener(r)
addrs, err := r.rp.GetReachableMembers(swim.MemberWithLabelAndValue(RoleKey, r.service))
if err != nil {
return err
}
for _, addr := range addrs {
labels := r.getLabelsMap()
r.ring.AddMembers(NewHostInfo(addr, labels))
}
r.shutdownWG.Add(1)
go r.refreshRingWorker()
r.isStarted = true
return nil
}
// Stop stops the resolver
func (r *ringpopServiceResolver) Stop() error {
r.ringLock.Lock()
defer r.ringLock.Unlock()
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
if r.isStopped {
return nil
}
if r.isStarted {
r.rp.RemoveListener(r)
r.ring = hashring.New(farm.Fingerprint32, replicaPoints)
r.listeners = make(map[string]chan<- *ChangedEvent)
close(r.shutdownCh)
}
if success := common.AwaitWaitGroup(&r.shutdownWG, time.Minute); !success {
r.logger.Warn("service resolver timed out on shutdown.")
}
return nil
}
// Lookup finds the host in the ring responsible for serving the given key
func (r *ringpopServiceResolver) Lookup(key string) (*HostInfo, error) {
r.ringLock.RLock()
defer r.ringLock.RUnlock()
addr, found := r.ring.Lookup(key)
if !found {
return nil, ErrInsufficientHosts
}
return NewHostInfo(addr, r.getLabelsMap()), nil
}
func (r *ringpopServiceResolver) AddListener(name string, notifyChannel chan<- *ChangedEvent) error {
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
_, ok := r.listeners[name]
if ok {
return ErrListenerAlreadyExist
}
r.listeners[name] = notifyChannel
return nil
}
func (r *ringpopServiceResolver) RemoveListener(name string) error {
r.listenerLock.Lock()
defer r.listenerLock.Unlock()
_, ok := r.listeners[name]
if !ok {
return nil
}
delete(r.listeners, name)
return nil
}
// HandleEvent handles updates from ringpop
func (r *ringpopServiceResolver) HandleEvent(event events.Event) {
// We only care about RingChangedEvent
e, ok := event.(events.RingChangedEvent)
if ok {
r.logger.Info("Received a ring changed event")
// Note that we receive events asynchronously, possibly out of order.
// We cannot rely on the content of the event, rather we load everything
// from ringpop when we get a notification that something changed.
r.refresh()
r.emitEvent(e)
}
}
func (r *ringpopServiceResolver) refresh() {
r.ringLock.Lock()
defer r.ringLock.Unlock()
r.ring = hashring.New(farm.Fingerprint32, replicaPoints)
addrs, err := r.rp.GetReachableMembers(swim.MemberWithLabelAndValue(RoleKey, r.service))
if err != nil {
// This should never happen!
r.logger.Fatalf("Error during ringpop refresh. Error: %v", err)
}
for _, addr := range addrs {
host := NewHostInfo(addr, r.getLabelsMap())
r.ring.AddMembers(host)
}
r.logger.Debugf("Current reachable members: %v", addrs)
}
func (r *ringpopServiceResolver) emitEvent(rpEvent events.RingChangedEvent) {
// Marshall the event object into the required type
event := &ChangedEvent{}
for _, addr := range rpEvent.ServersAdded {
event.HostsAdded = append(event.HostsAdded, NewHostInfo(addr, r.getLabelsMap()))
}
for _, addr := range rpEvent.ServersRemoved {
event.HostsRemoved = append(event.HostsRemoved, NewHostInfo(addr, r.getLabelsMap()))
}
for _, addr := range rpEvent.ServersUpdated {
event.HostsUpdated = append(event.HostsUpdated, NewHostInfo(addr, r.getLabelsMap()))
}
// Notify listeners
r.listenerLock.RLock()
defer r.listenerLock.RUnlock()
for name, ch := range r.listeners {
select {
case ch <- event:
default:
r.logger.WithFields(bark.Fields{`listenerName`: name}).Error("Failed to send listener notification, channel full")
}
}
}
func (r *ringpopServiceResolver) refreshRingWorker() {
defer r.shutdownWG.Done()
refreshTicker := time.NewTicker(defaultRefreshInterval)
defer refreshTicker.Stop()
for {
select {
case <-r.shutdownCh:
return
case <-refreshTicker.C:
r.refresh()
}
}
}
func (r *ringpopServiceResolver) getLabelsMap() map[string]string {
labels := make(map[string]string)
labels[RoleKey] = r.service
return labels
}