Basic use of Nacos (2) -- Nacos configuration center

Preface

Pre knowledge ： Nacos Basic use of （1）—— introduction
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One 、 Configuration center introduction

1、Spring Cloud Config

Spring Cloud Config It provides the support scheme of server and client for the external configuration of distributed system . On the configured server side, you can manage the central location of external properties for applications in all environments . Client and server conceptual Spring Environment and PropertySource Keep abstractions in sync , They are perfect for Spring Applications , But it can be used with applications running in any language . When an application is in the deployment pipeline, from development to testing to production , You can manage the configuration between these environments , And ensure that applications have everything they need to run when migrating . The server storage backend is used by default implementation git, Therefore, it is easy to support the configuration environment of marked version , And can be accessed by various tools for managing content . It's easy to add alternative implementations , And use Spring Configure them to insert .

Spring Cloud Config Contains Client and Server Two parts ,server Provide storage of configuration files 、 Provide the contents of the configuration file in the form of an interface ,client Get data through the interface 、 And based on this data to initialize their own applications .Spring cloud Use git or svn Store the configuration file , By default git.

2、Nacos Replace Config

Nacos It can be done with Spring, Spring Boot, Spring Cloud Integrate , And can replace Spring Cloud Eureka, Spring Cloud Config. adopt Nacos Server and spring-cloud-starter-alibaba-nacos-config Realize the dynamic change of configuration .

(1) Application scenarios

In the process of system development , Developers usually change some parameters that need to be changed 、 Variables are separated from the code and managed independently , In the form of a separate configuration file . The goal is to have static system artifacts or deliverables （ Such as WAR,JAR Bag, etc ） Better adapt to the actual physical operating environment . Configuration management is generally included in the process of system deployment , It is completed by system administrator or operation and maintenance personnel . Configuration change is an effective way to adjust the behavior of the system at runtime .

(2) Problem solved

If the unified configuration center is not used in the microservice Architecture , The problem is ：

1. Configuration files are scattered across projects , Inconvenient to maintain
2. Configure content security and permissions
3. After updating the configuration , The project needs to be restarted

(3)nacos Configuration center function ：

Centralized management of system configuration （ edit 、 Storage 、 distribution ）、 Dynamic update does not restart 、 Rollback configuration （ Change management 、 Historical version management 、 Change audit ） And all configuration related activities .

Two 、 Read Nacos Configuration center configuration file

1、 stay Nacos Create a unified profile

(1) Click the Create button

(2) Enter configuration information

Data ID The complete rule format is as follows

${prefix}-${spring.profiles.active}.${file-extension}

• prefix The default is the project configuration spring.application.name Value （ namely ：nacos-provider）, You can also configure items through spring.cloud.nacos.config.prefix To configure the .

• spring.profiles.active=dev That is, the current environment corresponds to profile. Be careful ： When spring.profiles.active It's empty time , Corresponding connector - There will be no ,dataId The splicing format of becomes ${prefix}.${file-extension}

• file-exetension To configure the data format of the content , You can use the configuration item spring.cloud.nacos.config.file-extension To configure the . Currently only supported properties and yaml type .

(3) Ensure that the configuration information is correct , Click on the confirmation

(4) Click the configuration list to see the configuration file

2. Take any module as an example

（1） stay service Of pom.xml Introduce dependency in

		<!--  Configuration center  -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>

（2） establish bootstrap.properties The configuration file

# Configure center address 
spring.cloud.nacos.config.server-addr=127.0.0.1:8848
#spring.profiles.active=dev
#  This configuration affects... In the unified configuration center dataId
spring.application.name=service-statistics-dev

（3） Before the project application.properties Content notes , Start the project to see the effect

The console outputs relevant information

2020-06-12 11:11:01.875  INFO 8676 --- [-127.0.0.1_8848] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration' of type [org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2020-06-12 11:11:02.464  INFO 8676 --- [-127.0.0.1_8848] o.s.c.a.n.c.NacosPropertySourceBuilder   : Loading nacos data, dataId: 'service-statistics-dev.properties', group: 'DEFAULT_GROUP'
2020-06-12 11:11:02.468  INFO 8676 --- [-127.0.0.1_8848] b.c.PropertySourceBootstrapConfiguration : Located property source: CompositePropertySource {
    name='NACOS', propertySources=[NacosPropertySource {
    name='service-statistics-dev-dev.properties'}, NacosPropertySource {
    name='service-statistics-dev.properties'}]}
2020-06-12 11:11:02.469  INFO 8676 --- [-127.0.0.1_8848] o.s.boot.SpringApplication               : The following profiles are active: dev

3、 Add ：springboot Profile load order

Actually yml and properties Files are the same principle , And on a project, either yml perhaps properties, The existence of one of two . Recommended yml, More concise .

bootstrap And application

（1） Loading order

bootstrap.properties/yml --> application.properties/yml --> application-dev.properties/yml

（2） Configuration difference

bootstrap.yml and application.yml Can be used to configure parameters .

bootstrap.yml It can be understood as some parameter configuration at the system level , These parameters will not change .
application.yml Can be used to define application level .

3、 ... and 、 Namespace

In actual development , There are usually many different environments （ Only by default public）, At this time, you can create different namespce, for example , Development 、 Three different environments for testing and production , Then use a set of nacos There are three different clusters namespace. In order to achieve multi environment isolation .

（1） Switch namespace

1 Click on namespace

2 New namespace

3 Click clone

4 The target space is specified as dev

5 stay bootstrap.properties Add configuration in

The value is a namespace id value

spring.cloud.nacos.config.namespace=c2074590-581c-4a5c-9d43-ea48953f5bf2

Four 、 Load multiple profiles

1 Separate application.properties, Comment out the port configuration
2 newly build port.properties

server.port=8008

3 stay bootstrap.properties Add configuration in

#  Load profile 
spring.cloud.nacos.config.ext-config[0].data-id=port.properties
#  Enable dynamic refresh configuration , Otherwise, the configuration file will be modified , Engineering cannot perceive 
spring.cloud.nacos.config.ext-config[0].refresh=true

4 Just restart the project

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