Spring Cloud Alibaba

This example project demonstrates how to integrate spring-cloud-starter-alibaba-sentinel into Spring Cloud applications to implement traffic management.

Sentinel is a traffic defense component designed to protect the stability of distributed systems. It manages traffic through several dimensions, including:

• Traffic Control: Limiting the flow of requests.
• Fuse Degradation: Automatically breaking circuits when service health declines.
• System Load Protection: Protecting the system from being overwhelmed by high load.

Spring Cloud Alibaba provides a one-stop solution for microservices development, allowing developers to use Alibaba's open-source middleware via the Spring Cloud programming model.

Currently included components:

• Sentinel: Protects service stability through traffic control, circuit breaking, degradation, and system load protection.
• Nacos: A dynamic service discovery, configuration management, and service management platform designed for cloud-native applications.
• RocketMQ: An Apache-incubated distributed messaging system providing low-latency, highly reliable message publishing and subscription services.
• Seata: An open-source distributed transaction solution (Apache project) providing high-performance and easy-to-use distributed transactions in microservice architectures.

This project is a demonstration of how to integrate the Seata Starter into a Spring Cloud Alibaba application to achieve distributed transaction management.

Seata is an open-source distributed transaction middleware from Alibaba designed to solve distributed transaction challenges in microservice architectures using an efficient, zero-intrusion approach.

Nacos provides service infrastructure including dynamic service discovery, configuration management, and service management. It is designed to help users build and manage microservice platforms flexibly.

Key integration capabilities:

• Seamless integration with Spring Cloud, Kubernetes/CNCF, and Dubbo.
• Enables building cloud-native applications centered around 'services'.

Nacos is a service infrastructure component that provides dynamic service discovery, configuration management, and service management. It is designed to help users build, deliver, and manage microservice platforms more flexibly.

Key characteristics include:

• Ecosystem Integration: Seamlessly integrates with Spring Cloud, Kubernetes/CNCF, and Dubbo.
• Cloud Native: Enables building modern, service-centric cloud-native applications.
• Future Roadmap: The Spring-Alibaba-Nacos-Config module is evolving to provide unified configuration hosting and lossless runtime rotation for Spring Boot (including Spring AI) and Spring Cloud applications. For standard business components, it will provide configuration injection and change callbacks via @NacosConfig and @NacosConfigListener annotations.

Spring Cloud Alibaba Scheduling supports two primary modes for handling timing tasks in distributed environments:

1. ShedLock: Uses an external database to manage distributed locks. When a task is annotated with @SchedulerLock, only one instance of the application will execute the task at a time.
2. SchedulerX: Integrates with Alibaba Cloud's managed SchedulerX service for enterprise-grade distributed scheduling.

In a distributed setup (e.g., running two instances on different ports), tasks without distributed locking will trigger on all instances, while tasks protected by the distributed mechanism (like @SchedulerLock with ShedLock) will only be triggered by a single instance.

Spring Cloud Alibaba Sidecar is a framework designed for the seamless integration of Spring Cloud with microservices written in non-Java (heterogeneous) languages. It works by using Nacos as a service registry, allowing the Sidecar to act as a bridge so that Spring Cloud microservices can discover and call non-Java services as if they were standard Java services.

To use Sidecar, you must:

1. Declare dependencies: Include the Sidecar and Nacos discovery starters.
2. Configure the Sidecar: Define the IP, port, and health check URL of the target non-Java service in your application.yml.
3. Start the services: Run both the Sidecar application and the target heterogeneous service.
4. Access via Gateway: Once registered in Nacos, the service can be accessed through the Spring Cloud Gateway using its application name.

http://127.0.0.1:8070/node-service/health.json

Nacos Config identifies configurations using a combination of dataId and group.

DataID Construction

In the Nacos Config Starter, the dataId is constructed as: ${prefix}.${spring.profiles.active}.${file-extension}

• prefix: Defaults to ${spring.application.name}. Can be customized via spring.cloud.nacos.config.prefix.
• spring.profiles.active: The current active Spring profile. If no profile is active, the format is ${prefix}.${file-extension}.
• file-extension: The format of the configuration content (e.g., properties). Can be customized via spring.cloud.nacos.config.file-extension. Currently, only properties is supported.

Group

• group: Defaults to DEFAULT_GROUP. Can be customized via spring.cloud.nacos.config.group.

The project is actively evolving its networking and communication layers:

• Proxyless Mesh: Exploration of Proxyless service mesh capabilities, with existing support for Routing and Xds-adapter. Future updates will focus on more cloud-native scenarios.
• RPC Enhancements: While currently relying on OpenFeign and RestTemplate, the project plans to enhance RPC capabilities by integrating gRPC and Dubbo's RPC solutions.
• Distributed Task Scheduling: Plans are in place to adapt open-source distributed task scheduling frameworks to fill the current gap in distributed scheduling support.