What data exchange methods do microservices use to interact with each other?

Microservices exchange data through several main methods:

1. HTTP/REST API — the most common way, where services communicate via HTTP requests, transmitting data in JSON or XML format.

2. gRPC — a high-performance remote procedure call protocol that uses Protocol Buffers for data serialization.

3. Messages through message brokers — for example, RabbitMQ, Kafka, where services exchange asynchronous messages, increasing reliability and scalability.

4. GraphQL — allows clients to request exactly the data they need, which is convenient for complex interactions.

An example of a simple HTTP request in Go to call another microservice:

resp, err := http.Get("http://service-url/api/data")
if err != nil {
    log.Fatal(err)
}
defer resp.Body.Close()
body, _ := ioutil.ReadAll(resp.Body)
fmt.Println(string(body))