对于线上的生产环境，通常对其都是有很高的要求，其中，高可用是不可或缺的一部分。必须保证服务是可用的，才能保证系统更好的运行，这是业务稳定的保证。 高可用一般分为两种：客户端高可用、服务端高可用
源码：https://gitee.com/laiyy0728/spring-cloud/tree/master/spring-cloud-config/spring-cloud-config-ha/spring-cloud-config-ha-client
客户端高可用 主要解决当前服务端不可用哪个的情况下，客户端依然可用正常启动。从客户端触发，不是增加配置中心的高可用性，而是降低客户端对配置中心的依赖程度，从而提高整个分布式架构的健壮性。
pom.xml
<dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-config-client</artifactId> </dependency> </dependencies>配置文件解析
@Component @ConfigurationProperties(prefix = ConfigSupportProperties.CONFIG_PREFIX) public class ConfigSupportProperties { /** * 加载的配置文件前缀 */ public static final String CONFIG_PREFIX = "spring.cloud.config.backup"; /** * 默认文件名 */ private final String DEFAULT_FILE_NAME = "fallback.properties"; /** * 是否启用 */ private boolean enabled = false; /** * 本地文件地址 */ private String fallbackLocation; public String getFallbackLocation() { return fallbackLocation; } public void setFallbackLocation(String fallbackLocation) { if (!fallbackLocation.contains(".")) { // 如果只指定了文件路径，自动拼接文件名 fallbackLocation = fallbackLocation.endsWith(File.separator) ? fallbackLocation : fallbackLocation + File.separator; fallbackLocation += DEFAULT_FILE_NAME; } this.fallbackLocation = fallbackLocation; } public boolean isEnabled() { return enabled; } public void setEnabled(boolean enabled) { this.enabled = enabled; } }自动装配实现类
@Configuration @EnableConfigurationProperties(ConfigSupportProperties.class) public class ConfigSupportConfiguration implements ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered { private final Logger logger = LoggerFactory.getLogger(getClass()); /** * 重中之重！！！！ * 一定要注意加载顺序！！！ * * bootstrap.yml 加载类：org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration 的加载顺序是 * HIGHEST_PRECEDENCE+10， * 如果当前配置类再其之前加载，无法找到 bootstrap 配置文件中的信息，继而无法加载到本地 * 所以当前配置类的装配顺序一定要在 PropertySourceBootstrapConfiguration 之后！ */ private final Integer orderNumber = Ordered.HIGHEST_PRECEDENCE + 11; @Autowired(required = false) private List<PropertySourceLocator> propertySourceLocators = Collections.EMPTY_LIST; @Autowired private ConfigSupportProperties configSupportProperties; /** * 初始化操作 */ @Override public void initialize(ConfigurableApplicationContext configurableApplicationContext) { // 判断是否开启 config server 管理配置 if (!isHasCloudConfigLocator(this.propertySourceLocators)) { logger.info("Config server 管理配置未启用"); return; } logger.info(">>>>>>>>>>>>>>> 检查 config Server 配置资源 <<<<<<<<<<<<<<<"); ConfigurableEnvironment environment = configurableApplicationContext.getEnvironment(); MutablePropertySources propertySources = environment.getPropertySources(); logger.info(">>>>>>>>>>>>> 加载 PropertySources 源：" + propertySources.size() + " 个"); // 判断配置备份功能是否启用 if (!configSupportProperties.isEnabled()) { logger.info(">>>>>>>>>>>>> 配置备份未启用，使用：{}.enabled 打开 <<<<<<<<<<<<<<", ConfigSupportProperties.CONFIG_PREFIX); return; } if (isCloudConfigLoaded(propertySources)) { // 可以从 spring cloud 中获取配置信息 PropertySource cloudConfigSource = getLoadedCloudPropertySource(propertySources); logger.info(">>>>>>>>>>>> 获取 config service 配置资源 <<<<<<<<<<<<<<<"); Map<String, Object> backupPropertyMap = makeBackupPropertySource(cloudConfigSource); doBackup(backupPropertyMap, configSupportProperties.getFallbackLocation()); } else { logger.info(">>>>>>>>>>>>>> 获取 config Server 资源配置失败 <<<<<<<<<<<<<"); // 不能获取配置信息，从本地读取 Properties backupProperty = loadBackupProperty(configSupportProperties.getFallbackLocation()); if (backupProperty != null) { Map backupSourceMap = new HashMap<>(backupProperty); PropertySource backupSource = new MapPropertySource("backupSource", backupSourceMap); propertySources.addFirst(backupSource); } } } @Override public int getOrder() { return orderNumber; } /** * 从本地加载配置 */ private Properties loadBackupProperty(String fallbackLocation) { logger.info(">>>>>>>>>>>> 正在从本地加载！<<<<<<<<<<<<<<<<<"); PropertiesFactoryBean propertiesFactoryBean = new PropertiesFactoryBean(); Properties properties = new Properties(); try { FileSystemResource fileSystemResource = new FileSystemResource(fallbackLocation); propertiesFactoryBean.setLocation(fileSystemResource); propertiesFactoryBean.afterPropertiesSet(); properties = propertiesFactoryBean.getObject(); if (properties != null){ logger.info(">>>>>>>>>>>>>>> 读取成功！<<<<<<<<<<<<<<<<<<<<<<<<"); } }catch (Exception e){ e.printStackTrace(); return null; } return properties; } /** * 备份配置信息 */ private void doBackup(Map<String, Object> backupPropertyMap, String fallbackLocation) { FileSystemResource fileSystemResource = new FileSystemResource(fallbackLocation); File file = fileSystemResource.getFile(); try { if (!file.exists()){ file.createNewFile(); } if (!file.canWrite()){ logger.info(">>>>>>>>>>>> 文件无法写入：{} <<<<<<<<<<<<<<<", fileSystemResource.getPath()); return; } Properties properties = new Properties(); Iterator<String> iterator = backupPropertyMap.keySet().iterator(); while (iterator.hasNext()) { String key = iterator.next(); properties.setProperty(key, String.valueOf(backupPropertyMap.get(key))); } FileOutputStream fileOutputStream = new FileOutputStream(fileSystemResource.getFile()); properties.store(fileOutputStream, "backup cloud config"); }catch (Exception e){ logger.info(">>>>>>>>>> 文件操作失败！ <<<<<<<<<<<"); e.printStackTrace(); } } /** * 将配置信息转换为 map */ private Map<String, Object> makeBackupPropertySource(PropertySource cloudConfigSource) { Map<String, Object> backupSourceMap = new HashMap<>(); if (cloudConfigSource instanceof CompositePropertySource) { CompositePropertySource propertySource = (CompositePropertySource) cloudConfigSource; for (PropertySource<?> source : propertySource.getPropertySources()) { if (source instanceof MapPropertySource){ MapPropertySource mapPropertySource = (MapPropertySource) source; String[] propertyNames = mapPropertySource.getPropertyNames(); for (String propertyName : propertyNames) { if (!backupSourceMap.containsKey(propertyName)) { backupSourceMap.put(propertyName, mapPropertySource.getProperty(propertyName)); } } } } } return backupSourceMap; } /** * config server 管理配置是否开启 */ private boolean isHasCloudConfigLocator(List<PropertySourceLocator> propertySourceLocators) { for (PropertySourceLocator propertySourceLocator : propertySourceLocators) { if (propertySourceLocator instanceof ConfigServicePropertySourceLocator) { return true; } } return false; } /** * 获取 config service 配置资源 */ private PropertySource getLoadedCloudPropertySource(MutablePropertySources propertySources) { if (!propertySources.contains(PropertySourceBootstrapConfiguration.BOOTSTRAP_PROPERTY_SOURCE_NAME)){ return null; } PropertySource<?> propertySource = propertySources.get(PropertySourceBootstrapConfiguration.BOOTSTRAP_PROPERTY_SOURCE_NAME); if (propertySource instanceof CompositePropertySource) { for (PropertySource<?> source : ((CompositePropertySource) propertySource).getPropertySources()) { // 如果配置源是 config service，使用此配置源获取配置信息 // configService 是 bootstrapProperties 加载 spring cloud 的实现：ConfigServiceBootstrapConfiguration if ("configService".equals(source.getName())){ return source; } } } return null; } /** * 判断是否可以从 spring cloud 中获取配置信息 */ private boolean isCloudConfigLoaded(MutablePropertySources propertySources) { return getLoadedCloudPropertySource(propertySources) != null; } }META-INF/spring.factories
org.springframework.cloud.bootstrap.BootstrapConfiguration=\ com.laiyy.gitee.confog.springcloudconfighaclientautoconfig.ConfigSupportConfigurationbootstrap.yml
spring: cloud: config: label: master uri: http://localhost:9090 name: config-simple profile: dev backup: enabled: true # 自定义配置 -- 是否启用客户端高可用配置 fallbackLocation: D:/cloud # 自动备份的配置文档存放位置application.yml
server: port: 9015 spring: application: name: spring-cloud-config-ha-client-config启动类
@SpringBootApplication @RestController public class SpringCloudConfigHaClientConfigApplication { public static void main(String[] args) { SpringApplication.run(SpringCloudConfigHaClientConfigApplication.class, args); } @Value("${com.laiyy.gitee.config}") private String config; @GetMapping(value = "/config") public String getConfig(){ return config; } }先后启动 config-server、config-client，查看config-client控制台输出：
Fetching config from server at : http://localhost:9090 Located environment: name=config-simple, profiles=[dev], label=master, version=ee39bf20c492b27c2d1b1d0ff378ad721e79a758, state=null Located property source: CompositePropertySource {name='configService', propertySources=[MapPropertySource {name='configClient'}, MapPropertySource {name='https://gitee.com/laiyy0728/config-repo.git/config-simple/config-simple-dev.yml'}]} >>>>>>>>>>>>>>> 检查 config Server 配置资源 <<<<<<<<<<<<<<< >>>>>>>>>>>>> 加载 PropertySources 源：11 个 >>>>>>>>>>>> 获取 config service 配置资源 <<<<<<<<<<<<<<< No active profile set, falling back to default profiles: default查看 d:/cloud，可见存在 fallback.properties 文件，打开文件，可见配置信息如下：
#backup cloud config #Wed Apr 10 14:49:36 CST 2019 config.client.version=ee39bf20c492b27c2d1b1d0ff378ad721e79a758 com.laiyy.gitee.config=dev \u73AF\u5883\uFF0Cgit \u7248 spring cloud config-----\!访问 http://localhost:9015/config ，可见打印信息如下：
config-client-ha-result
停止 server、client，删除 d:/cloud/fallback.properties，将 ConfigSupportConfiguration 的 orderNumber 改为 Ordered.HIGHEST_PRECEDENCE + 9，再次先后启动 config-server、config-client，查看控制 client 控制台输出如下：
>>>>>>>>>>>>>>> 检查 config Server 配置资源 <<<<<<<<<<<<<<< >>>>>>>>>>>>> 加载 PropertySources 源：10 个 >>>>>>>>>>>>>> 获取 config Server 资源配置失败 <<<<<<<<<<<<< Fetching config from server at : http://localhost:9090可见，PropertySources 源从原来的 11 个，变为 10 个。原因是 bootstrap.yml 的加载顺序问题。 在源码：org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration 中，其加载顺序为：Ordered.HIGHEST_PRECEDENCE + 10，而 ConfigSupportConfiguration 的加载顺序为 Ordered.HIGHEST_PRECEDENCE + 9，先于 bootstrap.yml 配置文件加载执行，所以无法获取到远程配置信息，继而无法备份配置信息。
重新进行第一步验证，然后将 config-server、config-client 停掉后，只启动 config-client，可见其控制台打印信息如下：
>>>>>>>>>>>>>>> 检查 config Server 配置资源 <<<<<<<<<<<<<<< >>>>>>>>>>>>> 加载 PropertySources 源：10 个 >>>>>>>>>>>>>> 获取 config Server 资源配置失败 <<<<<<<<<<<<< >>>>>>>>>>>> 正在从本地加载！<<<<<<<<<<<<<<<<< >>>>>>>>>>>>>>> 读取成功！<<<<<<<<<<<<<<<<<<<<<<<<访问 http://localhost:9015/config 正常返回信息。
由此验证客户端高可用成功
服务端高可用，一般情况下是通过与注册中心结合实现。通过 Ribbon 的负载均衡选择 Config Server 进行连接，来获取配置信息。
源码：https://gitee.com/laiyy0728/spring-cloud/tree/master/spring-cloud-config/spring-cloud-config-ha/spring-cloud-config-ha-server
eureka 选择使用 spring-cloud-eureka-server-simple
application.yml
server: port: 9016 spring: application: name: spring-cloud-config-ha-server-clientbootstrap.yml
spring: cloud: config: label: master name: config-simple profile: dev discovery: enabled: true # 是否从注册中心获取 config server service-id: spring-cloud-config-ha-server-app # 注册中心 config server 的 serviceId eureka: client: service-url: defauleZone: http://localhost:8761/eureka/ @SpringBootApplication @RestController public class SpringCloudConfigHaServerClientApplication { public static void main(String[] args) { SpringApplication.run(SpringCloudConfigHaServerClientApplication.class, args); } @Value("${com.laiyy.gitee.config}") private String config; @GetMapping(value = "/config") public String getConfig(){ return config; } }启用验证：访问 http://localhost:9016/config ,返回值如下：
config-client-ha-result
作者：laiyy0728 链接：https://www.jianshu.com/p/5de23aa2386e 来源：简书 简书著作权归作者所有，任何形式的转载都请联系作者获得授权并注明出处。
