无法在春季启动应用程序中从Consul读取配置 [英] Not able to read configuration from Consul in spring-boot application

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问题描述

我正在创建一个Spring Boot应用程序，它将从Consul读取配置，如数据库属性.但是我无法使用我的应用程序从Consul读取键值.以下是我正在尝试做的事情.

I am creating a Spring Boot application, which will read configuration like DB properties from Consul. But I am not able to read the key value from Consul using my application. Following is, what I am trying to do.

**pom.xml**
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.tuturself</groupId>
    <artifactId>spring-boot-consul</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <spring.retry.version>1.2.1.RELEASE</spring.retry.version>
        <consul.version>1.1.2.RELEASE</consul.version>
        <consul.discovery.version>1.1.2.RELEASE</consul.discovery.version>
        <jackson.version>2.8.1</jackson.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-consul-all</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-consul-discovery</artifactId>
            <version>${consul.discovery.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.retry</groupId>
            <artifactId>spring-retry</artifactId>
            <version>${spring.retry.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>${jackson.version}</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-consul-dependencies</artifactId>
                <version>1.2.1.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

</project>

以下是我的主班: 

@EnableRetry
@RefreshScope
@EnableDiscoveryClient
@SpringBootApplication
@ComponentScan("com.test.*")
public class SpringBootConsulApplication {

    private static ConsulConfiguration consulConfiguration;

    public static void main(String[] args) {
        try {
            String consulHost = System.getProperty("spring.cloud.consul.host");
            System.out.println("consulHost ::" + consulHost);
            String consulPort = System.getProperty("spring.cloud.consul.port");
            System.out.println("consulPort ::" + consulPort);
            String consulPrefix = System.getProperty("spring.cloud.consul.config.prefix");
            System.out.println("consulPrefix ::" + consulPrefix);
            new SpringApplicationBuilder(SpringBootConsulApplication.class).web(true).run(args);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

我正在使用@Value批注读取领事属性:

And I am reading the consul properties using the @Value annotation:

@Configuration
@EnableConfigurationProperties(PropertySourceBootstrapProperties.class)
public class ConsulConfiguration {

    @Value("${cassandra.host}")
    private String cassandraHost;

    @Value("${cassandra.user}")
    private String userName;

    @Value("${cassandra.password}")
    private String password;
}

我的bootstrap.yml在资源文件夹中:

spring:
  cloud:
    consul:
      host: localhost
      port: 8500
      enabled: true
      config:
        enabled: true
        prefix: config/application
        defaultContext: apps
        profileSeparator: '::'
  application:
    name: spring-boot-consul

Consul已启动并在我的本地系统中的localhost:8500上运行，其中有文件config/application/spring-boot-consul.yml文件；

Consul is up and running in my local system on localhost:8500 where I have the file config/application/spring-boot-consul.yml file;

spring:
  application:
    name: spring-boot-consul
cassandra:
  host: 127.0.0.1:9042,127.0.0.2:9042
  user: my_user
  password: my_pass
  pooling:
    maxThread: 10
    timeout: 50
  keyspace:
    name: test_keyspace
    readConsistency: ONE
    writeConsistency: ONE

当我处理应用程序时，它显示无法在我的ConsulConfiguration类中绑定cassandra.host.从而停止应用程序.任何提示，我在这里做错了什么?

When I am strating the application, it is showing not able to bind cassandra.host in my ConsulConfiguration class. Thus stopping the application. Any hints , What I am doing wrong here?

推荐答案

您可以找到一个有效的示例这里.

You can find a working example here.

您需要通过Consul UI或命令行将属性存储在Consul KV存储中. 领事代理不会从文件系统加载您的属性.要从命令行加载属性，请在Consul Agent启动并运行后使用以下命令.通过在文件名前添加@符号，可以从文件中读取YAML数据.

You need to store your properties in the Consul KV store either from Consul UI or from the command line. The Consul Agent will not load your properties from the file system. To load the properties from the command line, you can use the following command once the Consul Agent is up and running. The YAML data can be read from a file by prefixing the file name with the @ symbol.

./consul kv put config/application/data @spring-boot-consul.yml

其中config/application/data是键名.

如果数据已成功写入KV，则应获得以下响应，

If the data is successfully written in the KV, you should get the following response,

Success! Data written to: config/application/data

您还可以使用以下命令从KV中获取属性，

You can also fetch the properties from the KV by using the following command,

$ ./consul kv get config/application/data
cassandra:
  host: 127.0.0.1:9042,127.0.0.2:9042
  user: my_user
  password: my_pass

您还可以从Consul Web UI中查看属性，

You can also view the properties from the Consul Web UI,

您需要稍微修改bootstrap.yml.这是更改:

You need to modify your bootstrap.yml slightly. Here are the changes:

    将
  • prefix值设置为config
    • 将
  • defaultContext值设置为application
  • 将format添加到yaml

  • 通过data名称添加了data-key以获取YAML blob.

  • prefix value to config
  • defaultContext value to application
  • Added format to yaml

  • Added data-key by the name of data to fetch the YAML blob.

spring:
  profiles: default
  cloud:
    consul:
      host: localhost
      port: 8500
      config:
        enabled: true
        prefix: config
        defaultContext: application
        data-key: data
        profileSeparator: '::'
        format: yaml
  application:
    name: spring-boot-consul


@Configuration
@RefreshScope
public class ConsulConfiguration {

    @Value("${cassandra.host}")
    private String cassandraHost;

    @Value("${cassandra.user}")
    private String userName;

    @Value("${cassandra.password}")
    private String password;

    @PostConstruct
    public void postConstruct() {
        // to validate if properties are loaded
        System.out.println("** cassandra.host: " + cassandraHost);
        System.out.println("** cassandra.user: " + userName);
        System.out.println("** cassandra.password: " + password);
    }
}

更改为应用程序类，

@EnableRetry
@RefreshScope
@EnableDiscoveryClient
@EnableAutoConfiguration
@EnableConfigurationProperties
@SpringBootApplication
@ComponentScan("com.test.*")
public class SpringBootConsulApplication {

    public static void main(String[] args) {
        ...
    }

}

这篇关于无法在春季启动应用程序中从Consul读取配置的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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