Sentinel configuration information persistence and custom fuse downgrading processing logic

Writing in the front

In my previous article, “Getting Started with Microservices Architecture: Flow Control and Fuse downgrading solutions —-,” I gave a brief introduction to the use of Sentinel. However, one problem remains that the Sentinel configuration information has not been persisted and will be lost after the service restarts. In this article, we will tackle this problem.

Nacos was used as the Sentinel configuration information data source

In the default sentinel, the configuration information is stored directly in local memory and will be lost when the server restarts. In addition, fine-grained configurations require individual configuration operations for each resource, which is not conducive to the reuse of configuration information.

Sentinel dynamic rule configuration

In the sentinel data source extension, the following two modes are provided:

Pull mode: Clients regularly poll pull rules to a rule manager, such as RDBMS, files, or even VCS. The way to do this is simple, but the disadvantage is that changes cannot be captured in a timely manner;
Push mode: the rule center pushes the rules uniformly, and the client monitors the changes constantly by registering listeners, such as using Nacos and Zookeeper configuration centers. This method has better real-time performance and consistency assurance.

We will use the Nacos learned in the previous article as the data source of Sentinel configuration information (push pattern) to achieve persistent and dynamic configuration of Sentinel configuration information.

Before that, if you haven’t studied Nacos, then you need to learn first Nacos content, you can read my previous article introduction to the micro service architecture service registry findings and configuration center | Spring Cloud Alibaba Nacos “.

Introduction of depend on

First of all, we need to add sentinel’s NACOS data source dependency to the existing dependencies.

	<dependency>
        <groupId>com.alibaba.csp</groupId>
        <artifactId>sentinel-datasource-nacos</artifactId>
        <version>1.5.2</version>
    </dependency>
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Add the configuration

server:
  port: 9004
  tomcat:
    uri-encoding: UTF-8
spring:
  application:
    name: sentinel-demo
  cloud:
    nacos:
      server-addr: 172.17172.49.: 8848
    sentinel:
      transport:
        dashboard: 127.0. 01.: 8080
      datasource:
# Whatever your name is
        ds1:
          nacos:
            server-addr: ${spring.cloud.nacos.server-addr}
            dataId: ${spring.application.name}-sentinel
            groupId: DEFAULT_GROUP
# rule type, here is the limiting rule
            # see values: org. Springframework. Cloud. Alibaba. Sentinel. The datasource. RuleType
            rule-type: flow
        ds2:
          nacos:
            server-addr: ${spring.cloud.nacos.server-addr}
            dataId: ${spring.application.name}-sentinel-degrade
            groupId: DEFAULT_GROUP
# Demotion rule
            rule-type: degrade
        ds3:
          nacos:
            server-addr: ${spring.cloud.nacos.server-addr}
            dataId: ${spring.application.name}-sentinel-param-flow
            groupId: DEFAULT_GROUP
            # Hotspot parameter flow limiting rule
            rule-type: param-flow
        ds4:
          nacos:
            server-addr: ${spring.cloud.nacos.server-addr}
            dataId: ${spring.application.name}-sentinel-system
            groupId: DEFAULT_GROUP
            System adaptive current limiting
            rule-type: system
        ds5:
          nacos:
            server-addr: ${spring.cloud.nacos.server-addr}
            dataId: ${spring.application.name}-sentinel-authority
            groupId: DEFAULT_GROUP
            # Whitelist configuration
            rule-type: authority

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