go.opentelemetry.io/contrib/instrumentation/github.com/Shopify/sarama/otelsarama@v0.43.0/dispatcher.go (about)

     1  // Copyright The OpenTelemetry Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package otelsarama // import "go.opentelemetry.io/contrib/instrumentation/github.com/Shopify/sarama/otelsarama"
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  	"strconv"
    21  
    22  	"github.com/Shopify/sarama"
    23  
    24  	"go.opentelemetry.io/otel/attribute"
    25  	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
    26  	"go.opentelemetry.io/otel/trace"
    27  )
    28  
    29  type consumerMessagesDispatcher interface {
    30  	Messages() <-chan *sarama.ConsumerMessage
    31  }
    32  
    33  type consumerMessagesDispatcherWrapper struct {
    34  	d        consumerMessagesDispatcher
    35  	messages chan *sarama.ConsumerMessage
    36  
    37  	cfg config
    38  }
    39  
    40  func newConsumerMessagesDispatcherWrapper(d consumerMessagesDispatcher, cfg config) *consumerMessagesDispatcherWrapper {
    41  	return &consumerMessagesDispatcherWrapper{
    42  		d:        d,
    43  		messages: make(chan *sarama.ConsumerMessage),
    44  		cfg:      cfg,
    45  	}
    46  }
    47  
    48  // Messages returns the read channel for the messages that are returned by
    49  // the broker.
    50  func (w *consumerMessagesDispatcherWrapper) Messages() <-chan *sarama.ConsumerMessage {
    51  	return w.messages
    52  }
    53  
    54  func (w *consumerMessagesDispatcherWrapper) Run() {
    55  	msgs := w.d.Messages()
    56  
    57  	for msg := range msgs {
    58  		// Extract a span context from message to link.
    59  		carrier := NewConsumerMessageCarrier(msg)
    60  		parentSpanContext := w.cfg.Propagators.Extract(context.Background(), carrier)
    61  
    62  		// Create a span.
    63  		attrs := []attribute.KeyValue{
    64  			semconv.MessagingSystem("kafka"),
    65  			semconv.MessagingDestinationKindTopic,
    66  			semconv.MessagingDestinationName(msg.Topic),
    67  			semconv.MessagingOperationReceive,
    68  			semconv.MessagingMessageID(strconv.FormatInt(msg.Offset, 10)),
    69  			semconv.MessagingKafkaSourcePartition(int(msg.Partition)),
    70  		}
    71  		opts := []trace.SpanStartOption{
    72  			trace.WithAttributes(attrs...),
    73  			trace.WithSpanKind(trace.SpanKindConsumer),
    74  		}
    75  		newCtx, span := w.cfg.Tracer.Start(parentSpanContext, fmt.Sprintf("%s receive", msg.Topic), opts...)
    76  
    77  		// Inject current span context, so consumers can use it to propagate span.
    78  		w.cfg.Propagators.Inject(newCtx, carrier)
    79  
    80  		// Send messages back to user.
    81  		w.messages <- msg
    82  
    83  		span.End()
    84  	}
    85  	close(w.messages)
    86  }