What methods are used for interaction between individual microservices in the most common scenarios?

Interaction between microservices is usually carried out using the following methods:

1. HTTP/REST API — the most common way, where microservices exchange data via HTTP requests using REST architecture. A simple and understandable method, well-suited for synchronous interaction.

2. gRPC — a high-performance remote procedure call protocol that uses HTTP/2.. Suitable for microservices requiring fast and efficient communication.

3. Messages through brokers (Message Brokers) — asynchronous interaction through message exchange systems such as RabbitMQ, Kafka, NATS. Allows microservices to exchange events and data without direct calls to each other, increasing resilience and scalability.

4. GraphQL — sometimes used to aggregate data from multiple microservices into a single API.

Example in Go using HTTP to call another microservice:

package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    resp, err := http.Get("http://serviceB/api/data")
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        panic(err)
    }

    fmt.Println(string(body))
}

Thus, the choice of method depends on the requirements for performance, reliability, and system architecture.