普罗米修斯监测nacos导致微服务启动异常
请问大家是否遇到过在生产环境中，nacos监测通过正常url是可以正常访问数据的
但是将监测信息配置到普罗米修斯的配置文件中，就会导致，向这个正在被监测中nacos注册的服务，都会启动失败，无法正常启动成功是什么原因。
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- 这篇博客: 如何使用Nacos实现数据库连接的自动切换？中的 数据库宕机后，如何更新nacos配置实现数据库连接的自动切换？ 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
基于mybatis plus，一主一从的配置来实现数据源的配置的自动切换。mybatis plus的主库master，从库slave_1的配置如下：
spring.datasource.dynamic.primary=master spring.datasource.dynamic.datasource.master.username=root spring.datasource.dynamic.datasource.master.password=123456 spring.datasource.dynamic.datasource.master.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.dynamic.datasource.master.url=jdbc:mysql://127.0.0.1:3306/smcx_farm_products_mall?autoReconnectForPools=true&useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai spring.datasource.dynamic.datasource.slave_1.username=root spring.datasource.dynamic.datasource.slave_1.password=root spring.datasource.dynamic.datasource.slave_1.driver-class-name=com.mysql.cj.jdbc.Driver spring.datasource.dynamic.datasource.slave_1.url=jdbc:mysql://127.0.0.1:3306/smcx_farm_products_mall?autoReconnectForPools=true&useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai分析mybatis plus源码知道，mybatis plus定义DynamicRoutingDataSource实现数据源的动态切换，该类继承AbstractRoutingDataSource实现的，在获取数据库链接Connection时，根据配置判断从主从数据源获取连接，AbstractRoutingDataSource部分源码如下：
public abstract class AbstractRoutingDataSource extends AbstractDataSource { /** * 子类实现决定最终数据源 * * @return 数据源 */ protected abstract DataSource determineDataSource(); @Override public Connection getConnection() throws SQLException { return determineDataSource().getConnection(); } @Override public Connection getConnection(String username, String password) throws SQLException { return determineDataSource().getConnection(username, password); } }分析mybatis plus配置类DynamicDataSourceAutoConfiguration，可以知道，只需要实现可以监听nacos参数配置，可以动态切换数据源配置的DataSource即可，DynamicDataSourceAutoConfiguration的部分源码如下：
@Configuration @EnableConfigurationProperties(DynamicDataSourceProperties.class) @AutoConfigureBefore(DataSourceAutoConfiguration.class) @Import(DruidDynamicDataSourceConfiguration.class) @ConditionalOnProperty(prefix = DynamicDataSourceProperties.PREFIX, name = "enabled", havingValue = "true", matchIfMissing = true) public class DynamicDataSourceAutoConfiguration { /** * 数据源配置 * */ @Autowired private DynamicDataSourceProperties properties; @Bean @ConditionalOnMissingBean public DynamicDataSourceProvider dynamicDataSourceProvider() { return new YmlDynamicDataSourceProvider(properties); } /** * 在spring中注入动态数据源，注入自定义的DataSource即可扩展 * */ @Bean @ConditionalOnMissingBean public DataSource dataSource(DynamicDataSourceProvider dynamicDataSourceProvider) { DynamicRoutingDataSource dataSource = new DynamicRoutingDataSource(); dataSource.setPrimary(properties.getPrimary()); dataSource.setStrategy(properties.getStrategy()); dataSource.setProvider(dynamicDataSourceProvider); dataSource.setP6spy(properties.getP6spy()); dataSource.setStrict(properties.getStrict()); return dataSource; } }定义DynamicRoutingAndSwitchingDataSource，实现数据源动态路由，数据库配置自动切换。采用装饰模式扩展mybatis plus的DynamicRoutingDataSource的功能，实现EnvironmentChangeEvent事件的监听器ApplicationListener，在nacos配置修改的时候，监听配置的修改。Nacos配置在触发事件时，只会传输更新值的key/value值，所以，需要根据更新属性的key值，判断是否修改的数据库配置。其源码如下：
@Slf4j public class DynamicRoutingAndSwitchingDataSource extends AbstractRoutingDataSource implements ApplicationListener<EnvironmentChangeEvent>, EnvironmentAware, InitializingBean, DisposableBean { /** * mybatis plus 动态数据源Properties */ private DynamicDataSourceProperties dynamicDataSourceProperties; /** * 多数据源加载接口 */ private YmlDynamicDataSourceProvider dynamicDataSourceProvider; /** * 动态数据源Properties 属性key集合 */ private Set<String> propertyKeys; /** * mybatis plus动态路由数据源，使用装饰模式修饰 */ private DynamicRoutingDataSource dynamicRoutingDataSource; /** * spring Environment 配置对象 */ private Environment environment; public DynamicRoutingAndSwitchingDataSource(DynamicDataSourceProperties properties, DynamicDataSourceProvider provider) { this.dynamicDataSourceProperties = properties; this.dynamicDataSourceProvider = (YmlDynamicDataSourceProvider) provider; this.dynamicRoutingDataSource = this.buildDynamicRoutingDataSource(properties, provider); this.propertyKeys = Sets.newHashSet( ConfigProperty.MASTER_USERNAME_KEY, ConfigProperty.MASTER_PASSWORD_KEY, ConfigProperty.MASTER_DRIVER_CLASS_NAME_KEY, ConfigProperty.MASTER_RL_KEY, ConfigProperty.SLAVE_1_USERNAME_KEY, ConfigProperty.SLAVE_1_PASSWORD_KEY, ConfigProperty.SLAVE_1_DRIVER_CLASS_NAME_KEY, ConfigProperty.SLAVE_1_RL_KEY); } private DynamicRoutingDataSource buildDynamicRoutingDataSource(DynamicDataSourceProperties dynamicDataSourceProperties, DynamicDataSourceProvider provider) { DynamicRoutingDataSource dataSource = new DynamicRoutingDataSource(); dataSource.setPrimary(dynamicDataSourceProperties.getPrimary()); dataSource.setStrategy(dynamicDataSourceProperties.getStrategy()); dataSource.setProvider(provider); dataSource.setP6spy(dynamicDataSourceProperties.getP6spy()); dataSource.setStrict(dynamicDataSourceProperties.getStrict()); return dataSource; } /** * 监听配置修改的EnvironmentChangeEvent事件 */ @Override public void onApplicationEvent(EnvironmentChangeEvent event) { Set<String> keys; if (isNotDatasourceConfigChanged(keys = event.getKeys())) { log.info("keys {} are not database config!", JSON.toJSONString(keys)); return; } DynamicDataSourceProperties refreshProperties = this.dynamicDataSourceProperties; Map<String, DataSourceProperty> datasource = refreshProperties.getDatasource(); Map<String, Properties> changedPropertiesMap = this.getChangedProperties(); if (log.isDebugEnabled()) { log.debug("changed properties {}", JSON.toJSONString(changedPropertiesMap)); } for (Map.Entry<String, DataSourceProperty> entry : datasource.entrySet()) { String nodeName = entry.getKey(); Properties properties; if (Objects.isNull(properties = changedPropertiesMap.get(nodeName))) { log.info("node {} has no properties!changedPropertiesMap {}", nodeName, JSON.toJSONString(changedPropertiesMap)); continue; } DataSourceProperty dataSourceProperty = entry.getValue(); String userName; if (StringUtils.isNotBlank(userName = properties.getProperty(ConfigProperty.USERNAME))) { dataSourceProperty.setUsername(userName); } String password; if (StringUtils.isNotBlank(password = properties.getProperty(ConfigProperty.PASSWORD))) { dataSourceProperty.setPassword(password); } String driverClassName; if (StringUtils.isNotBlank(driverClassName = properties.getProperty(ConfigProperty.DRIVER_CLASS_NAME))) { dataSourceProperty.setDriverClassName(driverClassName); } String url; if (StringUtils.isNotBlank(url = properties.getProperty(ConfigProperty.URL))) { dataSourceProperty.setUrl(url); } } try { // 使用反射设置properties，避免初始化后，spring自动注入的DynamicDataSourceCreator无法获取 // @Autowired // private DynamicDataSourceCreator dynamicDataSourceCreator; Reflections.setFieldValue(this.dynamicDataSourceProvider, "properties", refreshProperties); this.dynamicRoutingDataSource = this.buildDynamicRoutingDataSource(refreshProperties, this.dynamicDataSourceProvider); // 重置数据源 this.dynamicRoutingDataSource.afterPropertiesSet(); } catch (Exception e) { throw new RuntimeException("refresh dynamic routing switch datasource error!", e); } } private boolean isNotDatasourceConfigChanged(Set<String> keys) { for (String key : keys) { if (propertyKeys.contains(key)) { return false; } } return true; } private boolean isMasterKey(String key) { return key.contains(ConfigProperty.MASTER); } private boolean isSlave1Key(String key) { return key.contains(ConfigProperty.SLAVE_1); } private boolean isUsernameKey(String key) { return key.contains(ConfigProperty.USERNAME); } private boolean isPasswordKey(String key) { return key.contains(ConfigProperty.PASSWORD); } private boolean isDriverClassNameKey(String key) { return key.contains(ConfigProperty.DRIVER_CLASS_NAME); } private boolean isUrlKey(String key) { return key.contains(ConfigProperty.URL); } private Map<String, Properties> getChangedProperties() { Map<String, Properties> propertiesMap = ImmutableMap.of(ConfigProperty.MASTER, new Properties(), ConfigProperty.SLAVE_1, new Properties()); for (String key : this.propertyKeys) { String value; if (StringUtils.isBlank(value = this.environment.getProperty(key))) { continue; } String propertyKey = this.convert2propertyKey(key); if (this.isMasterKey(key)) { propertiesMap.get(ConfigProperty.MASTER).setProperty(propertyKey, value); } else if (isSlave1Key(key)) { propertiesMap.get(ConfigProperty.SLAVE_1).setProperty(propertyKey, value); } } return propertiesMap; } private String convert2propertyKey(String key) { String propertyKey = key; if (this.isUsernameKey(key)) { propertyKey = ConfigProperty.USERNAME; } else if (this.isPasswordKey(key)) { propertyKey = ConfigProperty.PASSWORD; } else if (this.isDriverClassNameKey(key)) { propertyKey = ConfigProperty.DRIVER_CLASS_NAME; } else if (this.isUrlKey(key)) { propertyKey = ConfigProperty.URL; } return propertyKey; } /** * 设置Environment 属性 */ @Override public void setEnvironment(Environment environment) { this.environment = environment; } /** * 调用被装饰的dynamicRoutingDataSource的方法，获取指定的数据源 */ @Override protected DataSource determineDataSource() { return this.dynamicRoutingDataSource.determineDataSource(); } /** * 调用被装饰的dynamicRoutingDataSource的方法，初始化数据源 */ @Override public void afterPropertiesSet() throws Exception { this.dynamicRoutingDataSource.afterPropertiesSet(); } @Override public void destroy() throws Exception { this.dynamicRoutingDataSource.destroy(); } } public interface ConfigProperty { //////////// 数据源属性配置 //////////// String MASTER = "master"; String SLAVE_1 = "slave_1"; String USERNAME = "username"; String PASSWORD = "password"; String DRIVER_CLASS_NAME = "driver-class-name"; String URL = "url"; //////////// 数据源属性key配置 //////////// String MASTER_USERNAME_KEY = "spring.datasource.dynamic.datasource.master." + USERNAME; String MASTER_PASSWORD_KEY = "spring.datasource.dynamic.datasource.master." + PASSWORD; String MASTER_DRIVER_CLASS_NAME_KEY = "spring.datasource.dynamic.datasource.master." + DRIVER_CLASS_NAME; String MASTER_RL_KEY = "spring.datasource.dynamic.datasource.master." + URL; String SLAVE_1_USERNAME_KEY = "spring.datasource.dynamic.datasource.slave_1." + USERNAME; String SLAVE_1_PASSWORD_KEY = "spring.datasource.dynamic.datasource.slave_1." + PASSWORD; String SLAVE_1_DRIVER_CLASS_NAME_KEY = "spring.datasource.dynamic.datasource.slave_1." + DRIVER_CLASS_NAME; String SLAVE_1_RL_KEY = "spring.datasource.dynamic.datasource.slave_1." + URL; }自定义DynamicDataSourceAutoConfiguration，在spring中注入定义的DynamicRoutingAndSwitchingDataSource，其源码如下：
@Configuration @EnableConfigurationProperties(DynamicDataSourceProperties.class) @AutoConfigureBefore(DataSourceAutoConfiguration.class) @Import(DruidDynamicDataSourceConfiguration.class) @ConditionalOnProperty(prefix = DynamicDataSourceProperties.PREFIX, name = "enabled", havingValue = "true", matchIfMissing = true) public class DynamicDataSourceAutoConfiguration { @Autowired private DynamicDataSourceProperties properties; @Bean public DataSource dataSource(DynamicDataSourceProvider dynamicDataSourceProvider) { DynamicRoutingAndSwitchingDataSource dataSource = new DynamicRoutingAndSwitchingDataSource(properties, dynamicDataSourceProvider); return dataSource; } }结果测试，在nacos服务器修改从数据库的配置，如图：
代码调试时，后端数据库配置生效信息，如图：
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