How was the interaction between microservices organized?

Interaction between microservices is organized in several ways, depending on system requirements:

1. Synchronous interaction (HTTP/REST, gRPC):

   • One service makes a request to another and waits for a response.
   • Simple and understandable method, but can lead to delays and resilience issues.

2. Asynchronous interaction (messages, events):

   • Using message brokers (RabbitMQ, Kafka, NATS).
   • Services publish events, others subscribe and process them.
   • Increases scalability and resilience.

3. Using API Gateway:

   • Centralized entry point for clients.
   • Provides routing, authentication, data aggregation.

4. Data synchronization:

   • Using patterns like Event Sourcing or CQRS to synchronize state.

Example in Python using HTTP requests:

import requests

def call_service_b(data):
    response = requests.post('http://service-b/api/process', json=data)
    if response.status_code == 200:
        return response.json()
    else:
        # error handling
        pass

For asynchronous interaction, libraries for message brokers can be used, such as pika for RabbitMQ or confluent-kafka for Kafka.

The choice of method depends on requirements for delays, reliability, and system complexity.