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package client
import (
"context"
"io"
"time"
"github.com/chrislusf/seaweedfs/weed/pb/messaging_pb"
)
type Subscriber struct {
subscriberClient messaging_pb.SeaweedMessaging_SubscribeClient
}
func (mc *MessagingClient) NewSubscriber(subscriberId, namespace, topic string) (*Subscriber, error) {
stream, err := messaging_pb.NewSeaweedMessagingClient(mc.grpcConnection).Subscribe(context.Background())
if err != nil {
return nil, err
}
// send init message
err = stream.Send(&messaging_pb.SubscriberMessage{
Init: &messaging_pb.SubscriberMessage_InitMessage{
Namespace: namespace,
Topic: topic,
Partition: 0,
StartPosition: messaging_pb.SubscriberMessage_InitMessage_TIMESTAMP,
TimestampNs: time.Now().UnixNano(),
SubscriberId: subscriberId,
},
})
if err != nil {
return nil, err
}
// process init response
initResponse, err := stream.Recv()
if err != nil {
return nil, err
}
if initResponse.Redirect != nil {
// TODO follow redirection
}
return &Subscriber{
subscriberClient: stream,
}, nil
}
func (s *Subscriber) Subscribe(processFn func(m *messaging_pb.Message)) error {
for {
resp, listenErr := s.subscriberClient.Recv()
if listenErr == io.EOF {
return nil
}
if listenErr != nil {
return listenErr
}
processFn(resp.Data)
}
}
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