Implementing the earthquake stream consumer

Producing is not very valuable if you don’t have a consumer to consume data. Our second microservice, called earthquakeConsumer, is going to consume data from Apache Kafka. It has a similar code structure to our streaming API (Figure 8.5).

Figure 8.5: Earthquake consumer API structure

Let’s start from the configs folder. As in our first microservice in Chapter 5, we have a .env file inside the folder. The responsibility of this folder is to store relevant configurations. Here is what it looks like:

PORT=3002
#KAFKA Configuration
KAFKA_CLIENT_ID=earthquake-consumer-service
KAFKA_BROKERS=localhost:29092
KAFKA_TOPIC=earthquake-service-topic
KAFKA_GROUP_ID=earthquake-consumer-group

We introduced an additional configuration, KAFKA_GROUP_ID, which identifies the consumer group, allowing Kafka to balance partition assignments among consumers. It is a string property used to identify a collection of...