In modern software development, microservices architecture is becoming more and more popular due to its scalability, flexibility, and ease of independent deployment. However, security in microservices, especially authentication and authorization , becomes a bigger challenge than in monolithic architecture. This article will help you better understand these two concepts in microservices, common difficulties, and how to apply common solutions.
Authentication is the process of verifying the identity of a user or service. In other words, it answers the question "Who are you?" . Typically, a user will provide credentials such as an account name and password for authentication.
Authorization is the next step after authentication, which determines what a user or service is allowed to do in the system. It answers the question "What are you allowed to do?" . For example, a user may be allowed to view data but not allowed to delete or edit it.
In a monolithic architecture, the entire application runs in a single process, so session management and authorization are often done centrally, making it easy to share information between modules. However, microservices are a collection of small, independent services that run on different processes or even on different servers.
This leads to a number of challenges:
This method uses JSON Web Token (JWT) - a token string containing user information that is encrypted and digitally signed. The process is usually as follows:
The advantages of JWT are that it is stateless (no need to store state on the server), easy to scale, and suitable for distributed microservices environments.
However, managing token revocation and updating token permissions can be complex.
OAuth2 is a popular authorization standard that separates authentication and authorization from microservices. An Identity Provider (IdP) is responsible for authenticating users and issuing access tokens . Microservices only need to verify this token to grant access.
OpenID Connect extends OAuth2 with user authentication capabilities, providing additional identity information.
Advantage:
The downside is that it requires setting up and maintaining an IdP system or using a third-party service.
The API Gateway acts as a single entry point for all clients, performing centralized authentication and authorization before forwarding requests to microservices.
This reduces the need to duplicate security logic in each service, and makes it easier to control and monitor.
However, relying solely on the API Gateway for authentication without checking the services again can create a security vulnerability if an attacker bypasses the gateway.
Each microservice is responsible for authentication and authorization based on the received token. This is a Zero Trust approach, not trusting any component by default.
This is more secure but requires each service to be able to handle tokens and authorization policies, which can lead to code duplication and increased complexity.
Let's say you build an online ordering system with microservices:
Authentication and authorization process:
In the case of not using API Gateway, the client will send JWT directly to each microservice, and each service will handle authentication and authorization by itself.
Authentication and authorization in microservices architecture is an important and complex topic that requires careful design and technology considerations. Choosing the right approach depends on the system's scale, security requirements, and operational capabilities.
Understanding the basics of authentication and authorization, as well as popular models like JWT, OAuth2, API Gateway, and Zero Trust, will help you build effective, scalable, and maintainable security systems.
Hopefully this article has given you a practical overview to start implementing authentication and authorization solutions in microservices.