github.com/tickoalcantara12/micro/v3@v3.0.0-20221007104245-9d75b9bcbab9/service/events/client/stream.go (about)

     1  package client
     2  
     3  import (
     4  	gocontext "context"
     5  	"encoding/json"
     6  	"time"
     7  
     8  	pb "github.com/tickoalcantara12/micro/v3/proto/events"
     9  	"github.com/tickoalcantara12/micro/v3/service/client"
    10  	"github.com/tickoalcantara12/micro/v3/service/context"
    11  	"github.com/tickoalcantara12/micro/v3/service/events"
    12  	"github.com/tickoalcantara12/micro/v3/service/events/util"
    13  	log "github.com/tickoalcantara12/micro/v3/service/logger"
    14  )
    15  
    16  // NewStream returns an initialized stream service
    17  func NewStream() events.Stream {
    18  	return new(stream)
    19  }
    20  
    21  type stream struct {
    22  	Client pb.StreamService
    23  }
    24  
    25  func (s *stream) Publish(topic string, msg interface{}, opts ...events.PublishOption) error {
    26  	// parse the options
    27  	options := events.PublishOptions{
    28  		Timestamp: time.Now(),
    29  	}
    30  	for _, o := range opts {
    31  		o(&options)
    32  	}
    33  
    34  	// encode the message if it's not already encoded
    35  	var payload []byte
    36  	if p, ok := msg.([]byte); ok {
    37  		payload = p
    38  	} else {
    39  		p, err := json.Marshal(msg)
    40  		if err != nil {
    41  			return events.ErrEncodingMessage
    42  		}
    43  		payload = p
    44  	}
    45  
    46  	// execute the RPC
    47  	_, err := s.client().Publish(context.DefaultContext, &pb.PublishRequest{
    48  		Topic:     topic,
    49  		Payload:   payload,
    50  		Metadata:  options.Metadata,
    51  		Timestamp: options.Timestamp.Unix(),
    52  	}, client.WithAuthToken())
    53  
    54  	return err
    55  }
    56  
    57  func (s *stream) Consume(topic string, opts ...events.ConsumeOption) (<-chan events.Event, error) {
    58  	// parse options
    59  	options := events.ConsumeOptions{
    60  		AutoAck: true,
    61  		Context: gocontext.TODO(),
    62  	}
    63  
    64  	for _, o := range opts {
    65  		o(&options)
    66  	}
    67  
    68  	subReq := &pb.ConsumeRequest{
    69  		Topic:      topic,
    70  		Group:      options.Group,
    71  		Offset:     options.Offset.Unix(),
    72  		AutoAck:    options.AutoAck,
    73  		AckWait:    options.AckWait.Nanoseconds(),
    74  		RetryLimit: int64(options.GetRetryLimit()),
    75  	}
    76  
    77  	// start the stream
    78  	// TODO: potentially pass in the context defined by the user
    79  	stream, err := s.client().Consume(context.DefaultContext, subReq, client.WithAuthToken())
    80  	if err != nil {
    81  		return nil, err
    82  	}
    83  
    84  	evChan := make(chan events.Event)
    85  
    86  	go func() {
    87  		for {
    88  
    89  			ev, err := stream.Recv()
    90  			if err != nil {
    91  				log.Errorf("Error receiving from stream %s", err)
    92  				close(evChan)
    93  				stream.Close()
    94  				return
    95  			}
    96  
    97  			evt := util.DeserializeEvent(ev)
    98  			if !options.AutoAck {
    99  				evt.SetNackFunc(func() error {
   100  					return stream.SendMsg(&pb.AckRequest{Id: evt.ID, Success: false})
   101  				})
   102  				evt.SetAckFunc(func() error {
   103  					return stream.SendMsg(&pb.AckRequest{Id: evt.ID, Success: true})
   104  				})
   105  			}
   106  
   107  			select {
   108  			case evChan <- evt:
   109  			case <-options.Context.Done():
   110  				log.Info("Consuming stream context canceled")
   111  				close(evChan)
   112  				stream.Close()
   113  				return
   114  			}
   115  		}
   116  	}()
   117  
   118  	return evChan, nil
   119  }
   120  
   121  // this is a tmp solution since the client isn't initialized when NewStream is called. There is a
   122  // fix in the works in another PR.
   123  func (s *stream) client() pb.StreamService {
   124  	if s.Client == nil {
   125  		s.Client = pb.NewStreamService("events", client.DefaultClient)
   126  	}
   127  	return s.Client
   128  }