How did the services interact with each other?

In modern Go services, interaction between services is usually built on the following approaches:

• HTTP/REST API: services exchange data via HTTP requests using JSON or other formats.
• gRPC: an efficient protocol supporting binary serialization and contracts through protobuf.
• Messages through brokers: Kafka, RabbitMQ, or NATS for asynchronous interaction and event-driven architecture.

Example of interaction via HTTP in Go:

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

var data SomeDataType
json.NewDecoder(resp.Body).Decode(&data)

It is also important to consider:

• Error handling and timeouts.
• Authentication and authorization.
• Logging and request tracing for debugging.

Thus, services interact through well-defined interfaces, ensuring system scalability and fault tolerance.