Spring Cloud Building MicroServices Architecture (iv) Distributed configuration Center

Spring Cloud Config provides external configuration support for distributed systems for both the server and the client. The configuration server provides a centralized external configuration for all environments for each application. It implements a mapping of the spring environment and propertysource abstractions to both the server side and the client, so it can be used in applications that run in any other language, except for applications that are built by spring. As an application that can be tested or put into production by deploying pipelines, we can create configurations for these environments separately, and get the configuration of the corresponding environment to run when the environment needs to be migrated.

The configuration server uses Git to store configuration information by default, which facilitates versioning of the environment configuration and provides easy management and access to configuration content through the GIT client tool. Of course he also provides a way to store localized file systems, and here are two ways to use distributed configuration to store the configuration content of a microservices application's multi-environment.

Building Config Server

Building a config Server from spring cloud is simple and requires only three steps:

• • Create a REST API to return the From property of the configuration center, as follows:
  The dependency is introduced in Pom.xml spring-cloud-config-server and the full dependency configuration is as follows:

•     <parent> <groupId>org.springframework.boot</groupId> <artifactid>spring-boot-sta Rter-parent</artifactid> <version>1.5.2.RELEASE</version> <relativePath/> <!--Lo Okup parent from repository-</parent> <properties> <project.build.sourceencoding>utf -8</project.build.sourceencoding> <project.reporting.outputencoding>utf-8</ project.reporting.outputencoding> <java.version>1.7</java.version> </properties> &LT;DEP endencies> <dependency> <groupId>org.springframework.cloud</groupId> &lt            ;artifactid>spring-cloud-config-server</artifactid> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactid>spring-boot-starter-test</artif Actid> <scope>test</scope&Gt </dependency> </dependencies> <dependencyManagement> <dependencies> <de Pendency> <groupId>org.springframework.cloud</groupId> <artifactid>spri Ng-cloud-dependencies</artifactid> <version>Camden.SR6</version> <type& Gt;pom</type> <scope>Import</scope> </dependency> </dependencies> </dependencyManagement> &LT;BUILD&G        T                <plugins> <plugin> <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build>

  • Create a spring boot program main class and add @EnableConfigServer annotations to open config Server

  • @SpringBootApplication @enableconfigserver  Public class springcloudconfigcenterapplication {    publicstaticvoid  main (string[] args) {        springapplication.run (springcloudconfigcenterapplication. class , args);}    }

    • application.propertiesConfigure the service information and git information, such as:

    •  spring.application.name=config-serverserver.port  =7002# git management configuration Spring.cloud.config.server.git.uri  =https://" Span style= "COLOR: #008000" >github.com/xxx/ spring.cloud.config.server.git.searchpaths= Springcloud-config-center/config-repospring.cloud.config.server.git.username  =spring.cloud.config.server.git.password  = # # Turn on local configuration #spring.profiles.active  =native   #Config server retrieves the configuration file by default from the application's src /main/resource directory. You can also specify the retrieval location #spring.cloud.config.server by using the following configuration.  native . SEARCHLOCATIONS=FILE:F:/PR 

      • Spring.cloud.config.server.git.uri: Configuring the Git repository location
      • Spring.cloud.config.server.git.searchPaths: Configure the relative search location under the warehouse path to configure multiple
      • Spring.cloud.config.server.git.username: User name to access the GIT repository
      • Spring.cloud.config.server.git.password: Access the user password for the GIT repository

      Here, using a configuration center implemented with Spring Cloud config and using git to manage content, start the app and start the following content successfully.

      Spring Cloud Config also provides a way to configure the local storage. We only need to set properties spring.profiles.active=native , and config server will retrieve the configuration file from the app's directory by default src/main/resource . You can also spring.cloud.config.server.native.searchLocations=file:F:/properties/ specify the location of the configuration file through properties. Although Spring Cloud config provides such functionality, it is recommended to use GIT in order to support better functionality for managing content and versioning.

    • server-side validation

      In order to verify the configuration server completed above, a Config-repo directory was created under Http://github as the configuration repository, and the following four configuration files were built according to different environments:

      • Didispace.properties
      • didispace-dev.properties
      • didispace-test.properties
      • Didispace-prod.properties

      Where a from property is set with different values for each configuration file, such as:

      • from=git-default-1.0
      li>from=git-dev-1.0
      • from=git-test-1.0
      • from=git-prod-1.0

      In order to test version control, in master, We all add a suffix of 1.0, create a config-label-test branch at the same time, and use 2.0 as a suffix for the values in each configuration file.

      Once these preparations have been completed, we will be able to access our configuration directly through tools such as the browser or postman. The

      URL is mapped to the configuration file as follows:

      • /{application}/{profile}[/{label}]
      • /{application}-{profile}.yml
      • /{label}/{application}-{profile}.yml
      • /{application}-{profile}.properties
      • /{label}/{ Application}-{profile}.properties

      The URL above maps {application}-{profile}.properties for the corresponding configuration file, {label} corresponds to a different branch on Git, which defaults to master.

      We can try to construct different URLs to access different configuration contents

    • For example: To access the Config-label-test branch, configcenter application PROD environment, you can pass this url:http://localhost:7001/configcenter/prod/config-label-test
    • Micro-Server Mapping configuration

      After you have completed and verified the Configuration Service center, let's look at how we can get configuration information in the MicroServices app.

      • Create a spring boot application that introduces Spring-cloud-starter-config dependencies in Pom.xml, complete dependencies as follows:
        • <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-config-server</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactid>spring-boot-starter-test </artifactId>            <scope>test</scope>        </dependency>    </dependencies>

          <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-web</artifactid> </dependency>
        • Create the most basic spring boot startup main class
        • Create bootstrap.properties a configuration to specify config server, for example:

      • Spring.application.name: The {application} section in the corresponding pre-configuration file Spring.cloud.config.profile: {profile} in the corresponding pre-configuration file Section Spring.cloud.config.label: Git branch Spring.cloud.config.uri for the pre-configuration file: Address of the configuration center

        It is important to note that the above properties must be configured in the bootstrap.properties config section to be loaded correctly. Because the configuration of config will precede application.properties , and bootstrap.properties the load is before application.properties .

        • Create a REST API to return the From property of the configuration center, as follows:

        • Configure @Value("${from}") the From property in the service by binding.

          Launch the app and access: Http://localhost:7002/from, we can output the from content of the corresponding environment according to the configuration content.

Spring Cloud Building MicroServices Architecture (iv) Distributed configuration Center