序

本文主要研究下springboot2的LoggersEndpoint

实例

• GET /actuator/loggers

{  "levels": [    "OFF",    "ERROR",    "WARN",    "INFO",    "DEBUG",    "TRACE"  ],  "loggers": {    "ROOT": {      "configuredLevel": "INFO",      "effectiveLevel": "INFO"    },    "com": {      "configuredLevel": null,      "effectiveLevel": "INFO"    },    "com.example": {      "configuredLevel": null,      "effectiveLevel": "INFO"    },    "com.example.config": {      "configuredLevel": null,      "effectiveLevel": "INFO"    }  }}复制代码

• GET /actuator/loggers/com.example

{  "configuredLevel": null,  "effectiveLevel": "INFO"}复制代码

• POST

curl -i -X POST -H 'Content-Type: application/json' -d '{"configuredLevel": "ERROR"}' http://localhost:8080/actuator/loggers/com.exampleHTTP/1.1 204Date: Wed, 25 Apr 2018 14:54:41 GMT复制代码

LoggersEndpointAutoConfiguration

spring-boot-actuator-autoconfigure-2.0.1.RELEASE-sources.jar!/org/springframework/boot/actuate/autoconfigure/logging/LoggersEndpointAutoConfiguration.java

@Configurationpublic class LoggersEndpointAutoConfiguration {	@Bean	@ConditionalOnBean(LoggingSystem.class)	@Conditional(OnEnabledLoggingSystemCondition.class)	@ConditionalOnMissingBean	@ConditionalOnEnabledEndpoint	public LoggersEndpoint loggersEndpoint(LoggingSystem loggingSystem) {		return new LoggersEndpoint(loggingSystem);	}	static class OnEnabledLoggingSystemCondition extends SpringBootCondition {		@Override		public ConditionOutcome getMatchOutcome(ConditionContext context,				AnnotatedTypeMetadata metadata) {			ConditionMessage.Builder message = ConditionMessage					.forCondition("Logging System");			String loggingSystem = System.getProperty(LoggingSystem.SYSTEM_PROPERTY);			if (LoggingSystem.NONE.equals(loggingSystem)) {				return ConditionOutcome.noMatch(message.because("system property "						+ LoggingSystem.SYSTEM_PROPERTY + " is set to none"));			}			return ConditionOutcome.match(message.because("enabled"));		}	}}复制代码

这里根据loggingSystem，来创建LoggersEndpoint；另外还使用了OnEnabledLoggingSystemCondition

LoggersEndpoint

spring-boot-actuator-2.0.1.RELEASE-sources.jar!/org/springframework/boot/actuate/logging/LoggersEndpoint.java

@Endpoint(id = "loggers")public class LoggersEndpoint {	private final LoggingSystem loggingSystem;	/**	 * Create a new {@link LoggersEndpoint} instance.	 * @param loggingSystem the logging system to expose	 */	public LoggersEndpoint(LoggingSystem loggingSystem) {		Assert.notNull(loggingSystem, "LoggingSystem must not be null");		this.loggingSystem = loggingSystem;	}	@ReadOperation	public Map
    
      loggers() {		Collection
     
       configurations = this.loggingSystem				.getLoggerConfigurations();		if (configurations == null) {			return Collections.emptyMap();		}		Map
      
        result = new LinkedHashMap<>();		result.put("levels", getLevels());		result.put("loggers", getLoggers(configurations));		return result;	}	@ReadOperation	public LoggerLevels loggerLevels(@Selector String name) {		Assert.notNull(name, "Name must not be null");		LoggerConfiguration configuration = this.loggingSystem				.getLoggerConfiguration(name);		return (configuration == null ? null : new LoggerLevels(configuration));	}	@WriteOperation	public void configureLogLevel(@Selector String name,			@Nullable LogLevel configuredLevel) {		Assert.notNull(name, "Name must not be empty");		this.loggingSystem.setLogLevel(name, configuredLevel);	}	private NavigableSet
       
         getLevels() {		Set
        
          levels = this.loggingSystem.getSupportedLogLevels();		return new TreeSet<>(levels).descendingSet();	}	private Map
         
           getLoggers( Collection
          
            configurations) { Map
           
             loggers = new LinkedHashMap<>(configurations.size()); for (LoggerConfiguration configuration : configurations) { loggers.put(configuration.getName(), new LoggerLevels(configuration)); } return loggers; } /** * Levels configured for a given logger exposed in a JSON friendly way. */ public static class LoggerLevels { private String configuredLevel; private String effectiveLevel; public LoggerLevels(LoggerConfiguration configuration) { this.configuredLevel = getName(configuration.getConfiguredLevel()); this.effectiveLevel = getName(configuration.getEffectiveLevel()); } private String getName(LogLevel level) { return (level == null ? null : level.name()); } public String getConfiguredLevel() { return this.configuredLevel; } public String getEffectiveLevel() { return this.effectiveLevel; } }}复制代码
           
          
         
        
       
      
     
    

通过loggingSystem.getLoggerConfigurations()获取Collection，然后getLoggers方法将configurations转换为Map<String, LoggerLevels>

小结

LoggersEndpoint提供两个readOperation和一个writeOperation，分别用来读取和更改logger的level，非常实用。

doc