Hello, Habre! Today we will talk about the nuances of developing event-oriented microservices in Python. I will tell you why I think Python is suitable for developing microservices and what you should pay attention to when developing such microservices. My name Oleksiy NekrasovI am the leader of the Python department at MTS and the program director of Python courses at Skillbox. And the material is under execution.

Python, I choose you! Why?

The language has several advantages that make it suitable for developing microservices:

Simplicity and readability. Python is known for its simplicity and readability, which makes it ideal for rapid development and iteration. This feature also makes code easier to maintain and update, which is important for working with microservices.

A rich ecosystem. The language simply has a huge ecosystem of libraries and frameworks that can help in the development of microservices. For example, frameworks like Flask and FastAPI allow you to quickly and efficiently create web services, and libraries like Celery help you handle asynchronous tasks.

Support for asynchronous programming Python supports asynchronous programming with the asyncio and aiohttp modules. This allows efficient processing of a large number of parallel requests, which is a common task for microservices.

Containerization support. Python works well with containerization technologies like Docker, which is an important aspect of microservices architecture.

Of course, you can choose another language. For example, I can recommend Golang. Its advantages are productivity and built-in support for competitiveness. By itself, the choice of a user interface for microservices depends on a large number of factors. Performance requirements, the skills of the development team, and the specifics of the task are some of the most critical.

And what are event-oriented microservices?

This is the name given to the approach to the design of microservices, in which the main focus is on event processing. In this context, an event is any significant change in the system that can be processed by other services. For example, it can be creating a new user, changing the status of an order or updating a record in the database.

In an event-driven architecture, microservices communicate with each other by sending and receiving events, rather than through direct API requests. This can be implemented using a messaging system or an event broker such as Kafka or RabbitMQ.

The difference between event-oriented microservices and other approaches to microservices includes:

• Asynchrony. Event-driven microservices operate asynchronously, which can improve system performance and fault tolerance. Instead of waiting for a response from another service, a microservice can simply send an event and continue processing other tasks.

• Extensibility. Event-oriented microservices can be easily extended by adding new event handlers. This makes it easy to add new features and services without having to change existing code.

• Fault tolerance. Events can be stored and reprocessed in the event of a failure, improving system fault tolerance.

• Division of responsibility. Each microservice can focus on handling a specific type of event, which simplifies code design and maintenance.

It is important to remember that the event-oriented approach has its own complexities, including handling state, guaranteeing the order of events, and handling errors.

When developing such microservices, the developer needs to pay special attention to several aspects:

• Event design. Defining the types of events and the data structures they will transmit is a key design step. Events should be informative enough so that services can perform their functions on the basis of them, but not convey excessively detailed information that may violate the principles of encapsulation.

• Error handling. In an asynchronous, event-driven system, error handling can be complex. Error handling strategies must be thought out at different levels, from errors in individual event handlers to errors in the event delivery system.

• The order of events. In some cases, the order of events can be important. If order matters, you need to use messaging systems that can guarantee delivery order or use design patterns that can handle events out of order.

• Performance and scalability. Event-oriented systems can handle a large number of events, so it is important to consider performance and scalability when designing the system.

• Testing. Testing event-driven systems can be difficult due to their asynchronous nature and dependence on external services. Strategies for unit testing of event handlers, integration testing of service interactions, and load testing to verify system performance need to be devised.

• Monitoring and logging. In event-driven systems, it can be difficult to track what is happening in the system in real time, so it is important to have a good logging and monitoring system.

We avoid mistakes in development

While working on various projects over the past few years, I’ve seen developers make some very common mistakes.

For example, this is a load of events. The developer designs the microservice so that an event is generated for each change in the system. But this can lead to noise in the system, which creates certain difficulties for monitoring important events. It is better to focus on generating events that have a real meaning for other services.

In addition to this event can be even too complicated. It is also impossible to allow such things, I recommend simple and informative events. They should contain only the information needed to process the event. If it becomes too complex, it can make processing more difficult, making errors more likely.

Under no circumstances should mistakes be ignored. The fact is that in an asynchronous system, errors may not be as obvious as in a synchronous one. And ignoring mistakes can lead to serious problems in the long run. Therefore, it is important to have a strategy for handling and monitoring errors.

What knowledge and experience are needed to develop microservices

Here, knowledge of one programming language is indispensable. Other skills are also needed:

• Understanding microservices architecture. It is important for a developer to learn to understand the principles and patterns of microservices design. Among the critically important nuances are the distribution of responsibility, independence of services, state management and error handling.

• Work with databases. In the case of working on microservices, you will have to work with databases. Therefore, you need to know how to design databases, execute queries, and manage transactions.

• Working with APIs. Everything is logical here, because microservices interact with each other using APIs. Accordingly, the developer needs to know RESTful API design principles and/or GraphQL, gRPC/RPC, and HTTP and WebSocket.

• Good knowledge of the programming language chosen for work on microservices. If we take Python, this includes knowledge of the basic constructs of the language, standard libraries and popular frameworks such as Flask, FastAPI, Django, etc.

• Knowing how to perform tests, including modular, integration and functional. All this will help ensure the reliability and stability of the code.

And that’s not all: deploying and managing microservices will require at least basic knowledge and experience in DevOps and containerization. Knowledge of technologies such as Docker and Kubernetes as well as CI/CD principles is essential.

And the last thing is security, because the developer must know and understand the security of web applications, including protection against the main types of attacks, such as SQL injections, XSS and CSRF.

All this means that the development of microservices is a task for middle and senior developers. And novice developers can connect to perform specific tasks within the existing microservice.