micro/broker/memory.go

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package broker
import (
"context"
"errors"
"sync"
"github.com/google/uuid"
"github.com/unistack-org/micro/v3/logger"
maddr "github.com/unistack-org/micro/v3/util/addr"
mnet "github.com/unistack-org/micro/v3/util/net"
"github.com/unistack-org/micro/v3/util/rand"
)
type memoryBroker struct {
opts Options
addr string
sync.RWMutex
connected bool
Subscribers map[string][]*memorySubscriber
}
type memoryEvent struct {
opts Options
topic string
err error
message interface{}
}
type memorySubscriber struct {
id string
topic string
exit chan bool
handler Handler
opts SubscribeOptions
ctx context.Context
}
func (m *memoryBroker) Options() Options {
return m.opts
}
func (m *memoryBroker) Address() string {
return m.addr
}
func (m *memoryBroker) Connect(ctx context.Context) error {
m.Lock()
defer m.Unlock()
if m.connected {
return nil
}
// use 127.0.0.1 to avoid scan of all network interfaces
addr, err := maddr.Extract("127.0.0.1")
if err != nil {
return err
}
var rng rand.Rand
i := rng.Intn(20000)
// set addr with port
addr = mnet.HostPort(addr, 10000+i)
m.addr = addr
m.connected = true
return nil
}
func (m *memoryBroker) Disconnect(ctx context.Context) error {
m.Lock()
defer m.Unlock()
if !m.connected {
return nil
}
m.connected = false
return nil
}
func (m *memoryBroker) Init(opts ...Option) error {
for _, o := range opts {
o(&m.opts)
}
return nil
}
func (m *memoryBroker) Publish(ctx context.Context, topic string, msg *Message, opts ...PublishOption) error {
m.RLock()
if !m.connected {
m.RUnlock()
return errors.New("not connected")
}
subs, ok := m.Subscribers[topic]
m.RUnlock()
if !ok {
return nil
}
var v interface{}
if m.opts.Codec != nil {
buf, err := m.opts.Codec.Marshal(msg)
if err != nil {
return err
}
v = buf
} else {
v = msg
}
p := &memoryEvent{
topic: topic,
message: v,
opts: m.opts,
}
eh := m.opts.ErrorHandler
for _, sub := range subs {
if err := sub.handler(p); err != nil {
p.err = err
if sub.opts.ErrorHandler != nil {
eh = sub.opts.ErrorHandler
}
if eh != nil {
eh(p)
} else if m.opts.Logger.V(logger.ErrorLevel) {
m.opts.Logger.Error(m.opts.Context, err.Error())
}
continue
}
}
return nil
}
func (m *memoryBroker) Subscribe(ctx context.Context, topic string, handler Handler, opts ...SubscribeOption) (Subscriber, error) {
m.RLock()
if !m.connected {
m.RUnlock()
return nil, errors.New("not connected")
}
m.RUnlock()
options := NewSubscribeOptions(opts...)
id, err := uuid.NewRandom()
if err != nil {
return nil, err
}
sub := &memorySubscriber{
exit: make(chan bool, 1),
id: id.String(),
topic: topic,
handler: handler,
opts: options,
ctx: ctx,
}
m.Lock()
m.Subscribers[topic] = append(m.Subscribers[topic], sub)
m.Unlock()
go func() {
<-sub.exit
m.Lock()
var newSubscribers []*memorySubscriber
for _, sb := range m.Subscribers[topic] {
if sb.id == sub.id {
continue
}
newSubscribers = append(newSubscribers, sb)
}
m.Subscribers[topic] = newSubscribers
m.Unlock()
}()
return sub, nil
}
func (m *memoryBroker) String() string {
return "memory"
}
func (m *memoryBroker) Name() string {
return m.opts.Name
}
func (m *memoryEvent) Topic() string {
return m.topic
}
func (m *memoryEvent) Message() *Message {
switch v := m.message.(type) {
case *Message:
return v
case []byte:
msg := &Message{}
if err := m.opts.Codec.Unmarshal(v, msg); err != nil {
if m.opts.Logger.V(logger.ErrorLevel) {
m.opts.Logger.Error(m.opts.Context, "[memory]: failed to unmarshal: %v", err)
}
return nil
}
return msg
}
return nil
}
func (m *memoryEvent) Ack() error {
return nil
}
func (m *memoryEvent) Error() error {
return m.err
}
func (m *memorySubscriber) Options() SubscribeOptions {
return m.opts
}
func (m *memorySubscriber) Topic() string {
return m.topic
}
func (m *memorySubscriber) Unsubscribe(ctx context.Context) error {
m.exit <- true
return nil
}
// NewBroker return new memory broker
func NewBroker(opts ...Option) Broker {
return &memoryBroker{
opts: NewOptions(opts...),
Subscribers: make(map[string][]*memorySubscriber),
}
}