Springboot Actuator之七：actuator 中原生endpoint源码解析1

看actuator项目的包结构，以下：

本文中的介绍Endpoints。

Endpoints（端点）介绍

Endpoints 是 Actuator 的核心部分，它用来监视应用程序及交互，spring-boot-actuator中已经内置了很是多的Endpoints（health、info、beans、httptrace、shutdown等等），同时也容许咱们扩展本身的端点。

Endpoints 分红两类：原生端点和用户自定义端点：

1. 原生端点是在应用程序里提供的众多 restful api 接口，经过它们能够监控应用程序运行时的内部情况。原生端点又能够分红三类：
   • 应用配置类：能够查看应用在运行期间的静态信息：例如自动配置信息、加载的spring bean信息、yml文件配置信息、环境信息、请求映射信息；
   • 度量指标类：主要是运行期间的动态信息，例如堆栈、请求连、一些健康指标、metrics信息等；
   • 操做控制类：主要是指shutdown，用户能够发送一个请求将应用的监控功能关闭。
2. 自定义端点主要是指扩展性，用户能够根据本身的实际应用，定义一些比较关心的指标，在运行期进行监控。

咱们这里详细说明org.springframework.boot.actuate.endpoint中原生端点的实现.经过以下几个维度来进行分析:

• xxxEndpoint的做用
• xxxEndpoint的字段,构造器
• xxxEndpoint核心方法invoke 实现分析
• xxxEndpoint如何进行配置
• xxxEndpoint如何自动化装配

在org.springframework.boot.actuate.endpoint 中还有2个子包-jmx(可经过jmx协议访问),mvc(经过spring mvc 暴露,可经过接口进行访问,在下篇文章进行分析).这里咱们不关注这些,这看org.springframework.boot.actuate.endpoint 包下的类,类比较多,先看个类图吧,以下:

Endpoint接口：org.springframework.boot.actuate.endpoint.Endpoint.java

Endpoint接口：一个端点能够用于暴露（系统信息、操做入口等）信息。一般暴露方式是经过spring mvc的，如继承AbstractEndpoint的方式实现本身的endpoint。

public interface Endpoint<T> {

    // 端点的逻辑标识(字母、数字和下划线('_') 组成)
    String getId();

    // 端点是否启用
    boolean isEnabled();

    // 端点是否输出敏感数据
    boolean isSensitive();

    // 调用端点，并返回调用结果
    T invoke();
}

 其中泛型参数T为暴露的数据类型.方法的做用已经注释。

AbstractEndpoint抽象类

Endpoint的一个抽象子类：AbstractEndpoint(Endpoint接口实现的抽象基类),该类实现了EnvironmentAware,所以, AbstractEndpoint也就持有了Environment。

一、AbstractEndpoint 有以下属性:

// 匹配包括下划线的任何单词字符。相似但不等价于“[A-Za-z0-9_]”
private static final Pattern ID_PATTERN = Pattern.compile("\\w+");
// 经过EnvironmentAware接口注入
private Environment environment;
// 端点标识符
private String id;
// 是否默认敏感
private final boolean sensitiveDefault;
// 标识该端点是否暴露敏感信息
private Boolean sensitive;
// 是否端点可用
private Boolean enabled;

二、AbstractEndpoint方法

AbstractEndpoint方法实现了Endpoint接口中的getId, isEnabled, isSensitive,其中, getId只需返回AbstractEndpoint中的id属性便可,咱们分别来看下其余方法的实现:

2.一、isEnabled,代码以下:

@Override
public boolean isEnabled() {
        return EndpointProperties.isEnabled(this.environment, this.enabled);
}
@ConfigurationProperties(prefix = "endpoints")
public class EndpointProperties {

    private static final String ENDPOINTS_ENABLED_PROPERTY = "endpoints.enabled";

    private static final String ENDPOINTS_SENSITIVE_PROPERTY = "endpoints.sensitive";

    public static boolean isEnabled(Environment environment, Boolean enabled) {
        //一、若是AbstractEndpoint#enabled属性有值,则使用AbstractEndpoint的配置
        if (enabled != null) {
            return enabled;
        }
        //若是Environment 不等于null 而且Environment 配置有endpoints.enabled的属性,则返回其配置的值
        if (environment != null
                && environment.containsProperty(ENDPOINTS_ENABLED_PROPERTY)) {
            return environment.getProperty(ENDPOINTS_ENABLED_PROPERTY, Boolean.class);
        }
        //三、若是1和2没有值，则返回默认值true
        return true;
    }

2.二、isSensitive和isEnabled实现差很少,以下:

    @Override
    public boolean isSensitive() {
        return EndpointProperties.isSensitive(this.environment, this.sensitive,
                this.sensitiveDefault);
    }
@ConfigurationProperties(prefix = "endpoints")
public class EndpointProperties {

    private static final String ENDPOINTS_ENABLED_PROPERTY = "endpoints.enabled";

    private static final String ENDPOINTS_SENSITIVE_PROPERTY = "endpoints.sensitive";

    public static boolean isSensitive(Environment environment, Boolean sensitive,
            boolean sensitiveDefault) {
        //一、若是abstractEndpoint的sensitive有值，则使用这个配置
        if (sensitive != null) {
            return sensitive;
        }
        //二、若是environment 不等于null 而且 environment中配置有endpoints.sensitive的属性,则返回其配置值
        if (environment != null
                && environment.containsProperty(ENDPOINTS_SENSITIVE_PROPERTY)) {
            return environment.getProperty(ENDPOINTS_SENSITIVE_PROPERTY, Boolean.class);
        }
        //三、返回指定的默认值(默认为false)
        return sensitiveDefault;
    }

EnvironmentEndpoint

AbstractEndpoint的实现类之EnvironmentEndpoint--敏感数据

一、构造函数

@ConfigurationProperties(prefix = "endpoints.env")
public class EnvironmentEndpoint extends AbstractEndpoint<Map<String, Object>> {
    public EnvironmentEndpoint() {
        super("env");
    }
        //调用AbstractEndpoint的构造函数
    public AbstractEndpoint(String id) {
        this(id, true);
    }

最终,设置id为env,标识为敏感数据。

二、实现的invoke()，代码以下：

public Map<String, Object> invoke() {
    // 1. 先定义空的map返回值
    Map<String, Object> result = new LinkedHashMap<String, Object>();
    // 2. 将spring boot 中激活的profile 放入result中,key --> profile
    result.put("profiles", getEnvironment().getActiveProfiles());
    // 3. 得到PlaceholderSanitizingPropertyResolver --> 处理占位符,处理敏感数据
    PropertyResolver resolver = getResolver();
    // 4. 遍历environment 配置的PropertySource,依次处理之
    for (Entry<String, PropertySource<?>> entry : getPropertySourcesAsMap()
            .entrySet()) {
        PropertySource<?> source = entry.getValue();
        String sourceName = entry.getKey();
        if (source instanceof EnumerablePropertySource) {
            // 4.1 只针对EnumerablePropertySource 类型的PropertySource 进行处理--> 依次将属性添加到properties中,
            // 若是属性值为string,则在添加前进行占位符,数据脱敏的处理
            EnumerablePropertySource<?> enumerable = (EnumerablePropertySource<?>) source;
            Map<String, Object> properties = new LinkedHashMap<String, Object>();
            for (String name : enumerable.getPropertyNames()) {
                Object property = source.getProperty(name);
                Object resolved = property instanceof String
                        ? resolver.resolvePlaceholders((String) property) : property;
                //调用Sanitizer类进行脱敏
                properties.put(name, sanitize(name, resolved));
            }
            // 4.2 后置处理,该方法的实现是直接返回原始值,能够经过覆写的方式进行扩展
            properties = postProcessSourceProperties(sourceName, properties);
            if (properties != null) {
                // 4.3 若是不为空,则添加到result中
                result.put(sourceName, properties);
            }
        }
    }
    return result;
}

处理占位符,处理敏感数据：PlaceholderSanitizingPropertyResolver.java是EnvironmentEndpoint的内部类

public PropertyResolver getResolver() {
// 1. 实例化PlaceholderSanitizingPropertyResolver --> 处理占位符,处理敏感数据
PlaceholderSanitizingPropertyResolver resolver = new PlaceholderSanitizingPropertyResolver(
        getPropertySources(), this.sanitizer);
// 2. 设置ignoreUnresolvableNestedPlaceholders 为true
resolver.setIgnoreUnresolvableNestedPlaceholders(true);
return resolver;
}

PlaceholderSanitizingPropertyResolver继承了PropertySourcesPropertyResolver,这样就能对占位符进行处理了,又由于其内部持有Sanitizer(用于敏感数据脱敏),复写了getPropertyAsRawString,这样就能处理占位符,敏感数据了.代码以下:

        @Override
        protected String getPropertyAsRawString(String key) {
            String value = super.getPropertyAsRawString(key);
            return (String) this.sanitizer.sanitize(key, value);
        }

三、EnvironmentEndpoint的属性配置,因为EnvironmentEndpoint被@ConfigurationProperties(prefix = “endpoints.env”)注解,所以可经过以下配置进行个性化配置:

endpoints.env.id=env  
endpoints.env.sensitive=true  
endpoints.env.enabled=true

同时,又由于其声明了以下方法:

public void setKeysToSanitize(String... keysToSanitize) {
    this.sanitizer.setKeysToSanitize(keysToSanitize);
}

所以能够经过endpoints.env.keys-to-sanitize=xx,xx 来配置对指定的数据进行脱敏。脱敏配置

 四、EnvironmentEndpoint的自动化装配

EnvironmentEndpoint的自动化装配是在EndpointAutoConfiguration中,代码以下:

@Configuration
@AutoConfigureAfter({ FlywayAutoConfiguration.class, LiquibaseAutoConfiguration.class })
@EnableConfigurationProperties(EndpointProperties.class)
public class EndpointAutoConfiguration {
    @Bean
    @ConditionalOnMissingBean public EnvironmentEndpoint environmentEndpoint() {
        return new EnvironmentEndpoint();
    }

• @Bean注解：注册1个id为environmentEndpoint,类型为EnvironmentEndpoint的bean
• @ConditionalOnMissingBean注解：当beanFactory中不存在EnvironmentEndpoint类型的bean时注册

InfoEndpoint

AbstractEndpoint的实现类之InfoEndpoint，用于暴露应用信息。

其字段和构造器以下:

private final List<InfoContributor> infoContributors;
public InfoEndpoint(List<InfoContributor> infoContributors) {
    super("info", false);
    Assert.notNull(infoContributors, "Info contributors must not be null");
    this.infoContributors = infoContributors;
}

其内部持有了BeanFactory中全部InfoContributor类型的bean,其经过构造器注入。

二、invoke 实现以下:

public Map<String, Object> invoke() {
        Info.Builder builder = new Info.Builder();
        for (InfoContributor contributor : this.infoContributors) {
            contributor.contribute(builder);
        }
        Info build = builder.build();
        return build.getDetails();
}

经过遍历其内部的持有infoContributors,所以调用其contribute将info的数据添加到Info.Builder中,最后经过Info.Builder构建出Info,返回Info持有的details(建造者模式). Info中的details为Map.

InfoContributor接口用于向Info$Builder添加信息,关于这部分的内容,咱们后续文章有分析.这里就不在赘述了.

三、InfoEndpoint的属性配置

@ConfigurationProperties(prefix = "endpoints.info")
public class InfoEndpoint extends AbstractEndpoint<Map<String, Object>> {

所以可经过以下进行配置:

endpoints.info.id=info  
endpoints.info.sensitive=true  
endpoints.info.enabled=true

四、InfoEndpoint的自动化装配–>在EndpointAutoConfiguration中,代码以下:

    @Bean
    @ConditionalOnMissingBean public InfoEndpoint infoEndpoint() throws Exception {
        return new InfoEndpoint(this.infoContributors == null
                ? Collections.<InfoContributor>emptyList() : this.infoContributors);
    }

 

和EnvironmentEndpoint同样。

RequestMappingEndpoint：

AbstractEndpoint的实现类之RequestMappingEndpoint，因为RequestMappingEndpoint同时也实现了ApplicationContextAware接口，所以,在初始化该类时会注入applicationContext。这个类的做用是打印Spring MVC 映射信息。

一、构造函数

    public RequestMappingEndpoint() {
        super("mappings");
    }

所以, RequestMappingEndpoint的id为 mappings,默认为敏感。

二、invoke 实现以下:

public Map<String, Object> invoke() {
    Map<String, Object> result = new LinkedHashMap<String, Object>();
    // 1. 从handlerMappings中获取HandlerMapping,默认状况下handlerMappings是不存在数据的
    extractHandlerMappings(this.handlerMappings, result);
    // 2. 从applicationContext中获取AbstractUrlHandlerMapping类型的bean,依次将其注册的handler 添加进去.
    extractHandlerMappings(this.applicationContext, result);
    // 3. 从methodMappings中获取HandlerMapping,默认状况下methodMappings是不存在数据的
    extractMethodMappings(this.methodMappings, result);
    // 3. 从applicationContext中获取AbstractUrlHandlerMapping类型的bean,依次得到其持有的HandlerMethods,进行处理.
    extractMethodMappings(this.applicationContext, result);
    return result;
}

从applicationContext中获取

    protected void extractHandlerMappings(ApplicationContext applicationContext,
            Map<String, Object> result) {
        if (applicationContext != null) {
            Map<String, AbstractUrlHandlerMapping> mappings = applicationContext
                    .getBeansOfType(AbstractUrlHandlerMapping.class);
            for (Entry<String, AbstractUrlHandlerMapping> mapping : mappings.entrySet()) {
                Map<String, Object> handlers = getHandlerMap(mapping.getValue());
                for (Entry<String, Object> handler : handlers.entrySet()) {
                    result.put(handler.getKey(),
                            Collections.singletonMap("bean", mapping.getKey()));
                }
            }
        }
    }

得到AbstractUrlHandlerMapping类型的bean,此时有4个:
beanNameHandlerMapping=org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping
resourceHandlerMapping=org.springframework.web.servlet.handler.SimpleUrlHandlerMapping
faviconHandlerMapping=org.springframework.web.servlet.handler.SimpleUrlHandlerMapping
welcomePageHandlerMapping=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WelcomePageHandlerMapping

依次遍历mappings:
得到AbstractUrlHandlerMapping中注册的handler,key–> path,value–>handler
依次遍历handlerss,存入结果集中,存入的key–>AbstractUrlHandlerMapping的id,value={bean=AbstractUrlHandlerMapping中注册的handler的路径}

从methodMappings中获取HandlerMapping,默认状况下methodMappings是不存在数据的

从applicationContext中获取AbstractUrlHandlerMapping类型的bean,依次得到其持有的HandlerMethods,进行处理.代码以下:

    protected void extractMethodMappings(
            Collection<AbstractHandlerMethodMapping<?>> methodMappings,
            Map<String, Object> result) {
        for (AbstractHandlerMethodMapping<?> mapping : methodMappings) {
            Map<?, HandlerMethod> methods = mapping.getHandlerMethods();
            for (Map.Entry<?, HandlerMethod> entry : methods.entrySet()) {
                result.put(String.valueOf(entry.getKey()), Collections
                        .singletonMap("method", String.valueOf(entry.getValue())));
            }
        }
    }

得到AbstractUrlHandlerMapping类型的bean
依次遍历AbstractUrlHandlerMapping中注册的handler,添加至结果集中,key–> Handler 映射路径 ,value = {bean = AbstractHandlerMethodMapping的id,method=HandlerMethod}

三、RequestMappingEndpoint的配置

@ConfigurationProperties(prefix = "endpoints.mappings")
public class RequestMappingEndpoint extends AbstractEndpoint<Map<String, Object>>
        implements ApplicationContextAware {

从类上的配置注解，可知：

endpoints.mappings.enabled= # Enable the endpoint.
endpoints.mappings.id= # Endpoint identifier.
endpoints.mappings.sensitive= # Mark if the endpoint exposes sensitive information.

四、RequestMappingEndpoint的自动装配

    @Configuration
    @ConditionalOnClass(AbstractHandlerMethodMapping.class)
    protected static class RequestMappingEndpointConfiguration {

        @Bean
        @ConditionalOnMissingBean
        public RequestMappingEndpoint requestMappingEndpoint() {
            RequestMappingEndpoint endpoint = new RequestMappingEndpoint();
            return endpoint;
        }

    }

当知足以下两个条件时建立requestMappingEndpoint,即注册1个id为requestMappingEndpoint,类型为RequestMappingEndpoint的bean:

@ConditionalOnClass(AbstractHandlerMethodMapping.class) –> 在beanFactory中存在AbstractHandlerMethodMapping类型的bean时生效
@ConditionalOnMissingBean–>在beanFactory中不存在RequestMappingEndpoint类型的bean时生效

DumpEndpoint

AbstractEndpoint的实现类之DumpEndpoint，这个类的做用是打印线程信息，为敏感。

一、构造函数

    public DumpEndpoint() {
        super("dump");
    }

二、invoke()方法实现

    @Override
    public List<ThreadInfo> invoke() {
        return Arrays
                .asList(ManagementFactory.getThreadMXBean().dumpAllThreads(true, true));
    }

调用了ThreadMXBean的dumpAllThreads来返回全部活动线程的线程信息，并带有堆栈跟踪和同步信息。 当此方法返回时，返回数组中包含的一些线程可能已经终止。其中两个参数指的意义以下:

第1个–>若是为 true，则转储全部锁定的监视器。
第2个–>若是为 true，则转储全部锁定的可拥有同步器。

 ThreadMXBean怎么读取Thread信息见《JMX学习一》

三、DumpEndpoint的配置

@ConfigurationProperties(prefix = "endpoints.dump")
public class DumpEndpoint extends AbstractEndpoint<List<ThreadInfo>> {

 

可知：

endpoints.dump.enabled= # Enable the endpoint.
endpoints.dump.id= # Endpoint identifier.
endpoints.dump.sensitive= # Mark if the endpoint exposes sensitive information.

 

四、DumpEndpoint自动化装配:

@Bean
@ConditionalOnMissingBean public DumpEndpoint dumpEndpoint() {
    return new DumpEndpoint();
}

FlywayEndpoint

AbstractEndpoint的实现类之FlywayEndpoint，Flyway是一款开源的数据库版本管理工具。

ShutdownEndpoint

AbstractEndpoint的实现类之ShutdownEndpoint，做用是关闭应用。这个类继承了ApplicationAware,获得applicationContext，关闭spring容器调用applicationContext.close()方法。

一、构造函数

    public ShutdownEndpoint() {
        super("shutdown", true, false);
    }

id为shutdown，为敏感，关闭应用的endpoin默认是关闭的，不启用的。

二、invoke()方法实现

    @Override
    public Map<String, Object> invoke() {
                //若是context为null，直接返回
        if (this.context == null) {
            return NO_CONTEXT_MESSAGE;
        }
                //context不为null,先返回，再启动一个线程，在该线程中,先sleep 5秒后,而后调用了ShutdownEndpoint中持有的context的close方法进行关闭.
        try {
            return SHUTDOWN_MESSAGE;
        }
        finally {
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        Thread.sleep(500L);
                    }
                    catch (InterruptedException ex) {
                        Thread.currentThread().interrupt();
                    }
                    ShutdownEndpoint.this.context.close();
                }
            });
            thread.setContextClassLoader(getClass().getClassLoader());
            thread.start();
        }
    }

在返回后，还但愿作点啥，用try--finally。

三、ShutdownEndpoint的配置

@ConfigurationProperties(prefix = "endpoints.shutdown")
public class ShutdownEndpoint extends AbstractEndpoint<Map<String, Object>>
        implements ApplicationContextAware {

可知配置有：

endpoints.shutdown.enabled= # Enable the endpoint.
endpoints.shutdown.id= # Endpoint identifier.
endpoints.shutdown.sensitive= # Mark if the endpoint exposes sensitive information.

四、ShutdownEndpoint自动化装配:

@Bean
@ConditionalOnMissingBean
public ShutdownEndpoint shutdownEndpoint() {
    return new ShutdownEndpoint();
}

AutoConfigurationReportEndpoint

AbstractEndpoint的实现类之AutoConfigurationReportEndpoint，做用是暴露ConditionEvaluationReport.。

一、构造函数

    public AutoConfigurationReportEndpoint() {
        super("autoconfig");
    }

 

id为autoconfig，为敏感。

二、invoke()方法实现

    @Override
    public Report invoke() {
        return new Report(this.autoConfigurationReport);
    }

 

Report为其内部类

    @JsonPropertyOrder({ "positiveMatches", "negativeMatches", "exclusions" })
    @JsonInclude(Include.NON_EMPTY)
    public static class Report {

 

• @JsonPropertyOrder–>做用在类上，被用来指明当序列化时须要对属性作排序，它有2个属性:一个是alphabetic：布尔类型，表示是否采用字母拼音顺序排序，默认是为false，即不排序
• @JsonInclude–> Report中的属性值为空集合则不进行展现

Report 有以下字段:

// 匹配的
private final MultiValueMap<String, MessageAndCondition> positiveMatches;

// 不匹配的
private final Map<String, MessageAndConditions> negativeMatches;

// 去除的
private final List<String> exclusions;

// 通常为null
private final Report parent;

 

其中MessageAndCondition封装了ConditionAndOutcome中的condition,message以进行更好的展现(json友好).其类上声明了以下注解:

@JsonPropertyOrder({ "condition", "message" })

 

所以在进行输出的时候,先输出condition,再输出message.

构造器以下:

        public MessageAndCondition(ConditionAndOutcome conditionAndOutcome) {
            Condition condition = conditionAndOutcome.getCondition();
            ConditionOutcome outcome = conditionAndOutcome.getOutcome();
            this.condition = ClassUtils.getShortName(condition.getClass());
            if (StringUtils.hasLength(outcome.getMessage())) {
                this.message = outcome.getMessage();
            }
            else {
                this.message = (outcome.isMatch() ? "matched" : "did not match");
            }
        }

 

赋值condition为ConditionAndOutcome中的Condition的短类名.
赋值message:若是ConditionAndOutcome中的Message有值则直接赋值,不然,若是对应的Condition匹配,则赋值为matched,不然赋值为did not match。

回到report，构造器以下:

public Report(ConditionEvaluationReport report) {
this.positiveMatches = new LinkedMultiValueMap<String, MessageAndCondition>();
this.negativeMatches = new LinkedHashMap<String, MessageAndConditions>();
// 1. 经过report#getExclusions 得到不进行加载的bean
this.exclusions = report.getExclusions();
// 2. 
for (Map.Entry<String, ConditionAndOutcomes> entry : report
.getConditionAndOutcomesBySource().entrySet()) {
// 2.1 若是该配置生效条件都匹配,则加入到positiveMatches,不然,加入到negativeMatches
if (entry.getValue().isFullMatch()) {
    add(this.positiveMatches, entry.getKey(), entry.getValue());
}
else {
    add(this.negativeMatches, entry.getKey(), entry.getValue());
}
}
// 3. 若是report存在父report,则进行初始化Report 赋值为当前类的parent 属性
boolean hasParent = report.getParent() != null;
this.parent = (hasParent ? new Report(report.getParent()) : null);
}

 

经过ConditionEvaluationReport#getExclusions 得到不进行加载的bean,赋值为exclusions
调用ConditionEvaluationReport#getConditionAndOutcomesBySource 得到ConditionEvaluationReport中持有匹配信息,返回的map中,key–> 匹配类名,ConditionAndOutcomes–> 匹配结果.

依次遍历第2步的返回值–>若是该配置生效条件都匹配,则加入到positiveMatches,不然,加入到negativeMatches.其中add 代码以下:

        private void add(MultiValueMap<String, MessageAndCondition> map, String source,
                ConditionAndOutcomes conditionAndOutcomes) {
            String name = ClassUtils.getShortName(source);
            for (ConditionAndOutcome conditionAndOutcome : conditionAndOutcomes) {
                map.add(name, new MessageAndCondition(conditionAndOutcome));
            }
        }

 

所以positiveMatches,negativeMatches 中的key为配置类的简单类名.
若是report存在父report,则进行初始化Report 赋值为当前类的parent 属性.通常来讲，是不存在父report的

属性配置(由于有@ConfigurationProperties(prefix = “endpoints.autoconfig”) 注解):

endpoints.autoconfig.enabled= # Enable the endpoint.
endpoints.autoconfig.id= # Endpoint identifier.
endpoints.autoconfig.sensitive= # Mark if the endpoint exposes sensitive information.

 

自动装配:

一样仍是在EndpointAutoConfiguration中,代码以下:

@Bean
@ConditionalOnBean(ConditionEvaluationReport.class)
@ConditionalOnMissingBean(search = SearchStrategy.CURRENT)
public AutoConfigurationReportEndpoint autoConfigurationReportEndpoint() {
    return new AutoConfigurationReportEndpoint();
}

 

@Bean –> 注册1个id为autoConfigurationReportEndpoint,类型为AutoConfigurationReportEndpoint的bean
@ConditionalOnBean(ConditionEvaluationReport.class)–>beanFactory中存在ConditionEvaluationReport类型的bean时生效
@ConditionalOnMissingBean(search = SearchStrategy.CURRENT)–> 在当前上下文中不存在AutoConfigurationReportEndpoint类型的bean时生效

ConditionEvaluationReport

AutoConfigurationReportEndpoint 是经过ConditionEvaluationReport 来进行暴露信息.

ConditionEvaluationReport 字段以下:

private static final String BEAN_NAME = "autoConfigurationReport";

// 若是一个配置类中内部配置类不匹配,则在其外部类的所对应的ConditionAndOutcomes中添加1个AncestorsMatchedCondition
private static final AncestorsMatchedCondition ANCESTOR_CONDITION = new AncestorsMatchedCondition();

// key-->配置类类名,ConditionAndOutcomes-->匹配条件结果的封装
private final SortedMap<String, ConditionAndOutcomes> outcomes = new TreeMap<String, ConditionAndOutcomes>();

// 是否添加AncestorsMatchedCondition,默认为false
private boolean addedAncestorOutcomes;

// 父ConditionEvaluationReport,通常为null
private ConditionEvaluationReport parent;

// 去除加载的配置
private List<String> exclusions = Collections.emptyList();

// 在ConditionEvaluationReportAutoConfigurationImportListener#onAutoConfigurationImportEvent 添加,用于保存尚未
// 执行判断的class
private Set<String> unconditionalClasses = new HashSet<String>();

ConditionEvaluationReport 实例化过程以下:

在SpringApplication#run中会调用AbstractApplicationContext#refresh,在refresh会调用PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors,在该方法中最终会调用到AutoConfigurationImportSelector#selectImports方法.在该方法中会调用fireAutoConfigurationImportEvents,代码以下:AutoConfigurationImportSelector.fireAutoConfigurationImportEvents()

    private void fireAutoConfigurationImportEvents(List<String> configurations,
            Set<String> exclusions) {
        List<AutoConfigurationImportListener> listeners = getAutoConfigurationImportListeners();
        if (!listeners.isEmpty()) {
            AutoConfigurationImportEvent event = new AutoConfigurationImportEvent(this,
                    configurations, exclusions);
            for (AutoConfigurationImportListener listener : listeners) {
                invokeAwareMethods(listener);
                listener.onAutoConfigurationImportEvent(event);
            }
        }
    }

 

会加载/META-INF/spring.factories 中配置的org.springframework.boot.autoconfigure.AutoConfigurationImportListener,实例化后,依次调用其onAutoConfigurationImportEvent 方法. spring.factories 配置以下:

org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener

所以此处会调用ConditionEvaluationReportAutoConfigurationImportListener#onAutoConfigurationImportEvent.代码以下:

    @Override
    public void onAutoConfigurationImportEvent(AutoConfigurationImportEvent event) {
        if (this.beanFactory != null) {
            ConditionEvaluationReport report = ConditionEvaluationReport
                    .get(this.beanFactory);
            report.recordEvaluationCandidates(event.getCandidateConfigurations());
            report.recordExclusions(event.getExclusions());
        }
    }

 

A、实例化ConditionEvaluationReport,代码以下:

public static ConditionEvaluationReport get(
ConfigurableListableBeanFactory beanFactory) {
    synchronized (beanFactory) {
        ConditionEvaluationReport report;
        // 1. 若是当前beanFactory包含autoConfigurationReport定义的话,就从beanFactory中获取,
        if (beanFactory.containsSingleton(BEAN_NAME)) {
            report = beanFactory.getBean(BEAN_NAME,         ConditionEvaluationReport.class);
        }
        else {
            // 不然就实例化一个,而后进行注册
            report = new ConditionEvaluationReport();
            beanFactory.registerSingleton(BEAN_NAME, report);
        }
        // 2. 若是存在父容器的话,就从父容器中获取。
        locateParent(beanFactory.getParentBeanFactory(), report);
        return report;
    }
}

 

若是当前beanFactory包含autoConfigurationReport定义的话,就从beanFactory中获取,不然就实例化一个,而后进行注册

若是存在父容器的话,就从父容器中获取,并将其赋值为当前context中得到的ConditionEvaluationReport的父ConditionEvaluationReport.代码以下:

    private static void locateParent(BeanFactory beanFactory,
            ConditionEvaluationReport report) {
        if (beanFactory != null && report.parent == null
                && beanFactory.containsBean(BEAN_NAME)) {
            report.parent = beanFactory.getBean(BEAN_NAME,
                    ConditionEvaluationReport.class);
        }
    }

 

通常都是null,不会执行的。

B、设置unconditionalClasses为event#getCandidateConfigurations的返回值。
C、设置exclusions为event#getExclusions的返回值。

在AutoConfigurationReportEndpoint中是经过Report来进行暴露信息的,而在其构造器中,调用了ConditionEvaluationReport#getConditionAndOutcomesBySource方法,代码以下:

public Map<String, ConditionAndOutcomes> getConditionAndOutcomesBySource() {
    if (!this.addedAncestorOutcomes) {
        // 1. 若是addedAncestorOutcomes 设为false,则依次遍历outcomes,若是一个配置类中内部配置类不匹配,则在其外部类的所对应的ConditionAndOutcomes中添加1个AncestorsMatchedCondition
        for (Map.Entry<String, ConditionAndOutcomes> entry : this.outcomes.entrySet()) {
            if (!entry.getValue().isFullMatch()) {
                addNoMatchOutcomeToAncestors(entry.getKey());
            }
        }
        this.addedAncestorOutcomes = true;
    }
    return Collections.unmodifiableMap(this.outcomes);
}

 

若是addedAncestorOutcomes 设为false,则依次遍历outcomes,若是一个配置类中内部配置类不匹配,则在其外部类的所对应的ConditionAndOutcomes中添加1个AncestorsMatchedCondition

返回outcomes.

问题来了, outcomes 中的数据是如何添加的?

答案: 有2处.

仍是在AutoConfigurationImportSelector#selectImports中,会调用其filter方法.代码以下

private List<String> filter(List<String> configurations,
AutoConfigurationMetadata autoConfigurationMetadata) {
    long startTime = System.nanoTime();
    String[] candidates = configurations.toArray(new     String[configurations.size()]);
    boolean[] skip = new boolean[candidates.length];
    boolean skipped = false;
    // 1. 获取META-INFspring.factories/中配置的org.springframework.boot.autoconfigure.AutoConfigurationImportFilter,.OnClassCondition.依次进行遍历之
    // 此时得到的是org.springframework.boot.autoconfigure.condition
    for (AutoConfigurationImportFilter filter : getAutoConfigurationImportFilters()) {
        // 1.1 进行属性注入
        invokeAwareMethods(filter);
        // 1.2 调用AutoConfigurationImportFilter#match 进行判断,依次遍历其返回值,若是返回的是false,则说明该配置为跳过,并将skipped设置为true
        // 得到AutoConfigurationMetadata中配置的            ConditionalOnClass,若是不会空,则依次遍历之,看是否在当前类路径下存在
        // 若是不匹配的话,则调用            ConditionEvaluationReport.#ecordConditionEvaluation 进行记录
        // 因为此时AutoConfigurationMetadata 什么都没有配置,所以此步骤至关于空操做,最终会在第2步返回
        boolean[] match = filter.match(candidates, autoConfigurationMetadata);
        for (int i = 0; i < match.length; i++) {
            if (!match[i]) {
                skip[i] = true;
                skipped = true;
            }
        }
    }
    // 2. 若是skipped 等于false,则直接返回configurations,说明没有配置是须要跳过的
    if (!skipped) {
        return configurations;
    }
    // 3. 依次遍历candidates,若是该配置是不进行跳过的,则添加至result中进行返回
    List<String> result = new ArrayList<String>(candidates.length);
    for (int i = 0; i < candidates.length; i++) {
        if (!skip[i]) {
            result.add(candidates[i]);
        }
    }
    return new ArrayList<String>(result);
}

 

获取META-INFspring.factories/中配置的org.springframework.boot.autoconfigure.AutoConfigurationImportFilter,.OnClassCondition.依次进行遍历之.此时得到的是org.springframework.boot.autoconfigure.condition
进行属性注入
调用AutoConfigurationImportFilter#match 进行判断,依次遍历其返回值,若是返回的是false,则说明该配置为跳过,并将skipped设置为true.因为此时调用的是OnClassCondition,其判断逻辑为得到AutoConfigurationMetadata中配置的ConditionalOnClass,若是不会空,则依次遍历之,看是否在当前类路径下存在.若是不匹配的话,则调用ConditionEvaluationReport#ecordConditionEvaluation 进行记录.因为此时AutoConfigurationMetadata 什么都没有配置,所以此步骤至关于空操做,最终会在第2步返回

若是skipped 等于false,则直接返回configurations,说明没有配置是须要跳过的
依次遍历candidates,若是该配置是不进行跳过的,则添加至result中进行返回

在ConfigurationClassParser#processConfigurationClass进行解析加载配置类时,会调用ConditionEvaluator#shouldSkip,在该方法中,会所以遍历配置类配置的@Conditional所对应的处理类.此时,若是处理类是SpringBootCondition的子类的话,就会调用ConditionEvaluationReport进行记录匹配结果. 代码以下:

private void recordEvaluation(ConditionContext context, String classOrMethodName,
ConditionOutcome outcome) {
    if (context.getBeanFactory() != null) {
        ConditionEvaluationReport.get(context.getBeanFactory())
.recordConditionEvaluation(classOrMethodName, this, outcome);
    }
}

 

LiquibaseEndpoint

默认不生效,这里就不进行分析了
BeansEndpoint

BeansEndpoint的做用 –> 暴露关于beans的json视图.若是Environment 中设置了spring.liveBeansView.mbeanDomain,则全部spring 上下文的bean都会展现.不然只会展现当前的上下文中的bean.默认是没有配置的

BeansEndpoint,构造器以下：

    public BeansEndpoint() {
        super("beans");
    }

 

id为beans,默认为敏感

BeansEndpoint的字段以下:

// 继承自LiveBeansView,用于生成json格式的数据
private final HierarchyAwareLiveBeansView liveBeansView = new HierarchyAwareLiveBeansView();

// json 解析器对象
private final JsonParser parser = JsonParserFactory.getJsonParser();

 

因为BeansEndpoint实现了ApplicationContextAware接口,所以当前初始化时,会调用其setApplicationContext方法,代码以下:

    @Override
    public void setApplicationContext(ApplicationContext context) throws BeansException {
        if (context.getEnvironment()
                .getProperty(LiveBeansView.MBEAN_DOMAIN_PROPERTY_NAME) == null) {
            this.liveBeansView.setLeafContext(context);
        }
    }

 

若是没有设置spring.liveBeansView.mbeanDomain的属性,则将HierarchyAwareLiveBeansView中的leafContext设置为传入的ApplicationContext(一般是当前应用所对应的上下文)

invoke实现以下:

    @Override
    public List<Object> invoke() {
        return this.parser.parseList(this.liveBeansView.getSnapshotAsJson());
    }

 

调用HierarchyAwareLiveBeansView#getSnapshotAsJson 生成json串.代码以下：

public String getSnapshotAsJson() {

    if (this.leafContext == null) {
        return super.getSnapshotAsJson();
    }
    // 2. 将leafContext的整个继承关系都添加到contexts中,即:若是给定的leafContext 存在父context,则一直递归的添加至contexts
    // 直至顶级容器,而后调用LiveBeansView#generateJson 来生成json串
    return generateJson(getContextHierarchy());
}

 

若是leafContext 等于null,则调用LiveBeansView#getSnapshotAsJson来生成json串.通常都会执行第2步

将leafContext的整个继承关系都添加到contexts中,即:若是给定的leafContext 存在父context,则一直递归的添加至contexts.代码以下:

        private Set<ConfigurableApplicationContext> getContextHierarchy() {
            Set<ConfigurableApplicationContext> contexts = new LinkedHashSet<ConfigurableApplicationContext>();
            ApplicationContext context = this.leafContext;
            while (context != null) {
                contexts.add(asConfigurableContext(context));
                context = context.getParent();
            }
            return contexts;
        }

 

将leafContext的整个继承关系都添加到contexts中,即:若是给定的leafContext 存在父context,则一直递归的添加至contexts直至顶级容器。

调用LiveBeansView#generateJson 来生成json串.在该方法中没有使用第3方的json解析库的目的是为了不对其进行依赖.返回的格式为数组格式.代码以下:

因为BeansEndpoint声明了@ConfigurationProperties(prefix = “endpoints.beans”),所以能够经过以下属性来配置:

endpoints.beans.id
endpoints.beans.sensitive
endpoints.beans.enabled

 

自动化配置:

beansEndpoint 是在EndpointAutoConfiguration 中进行配置的,代码以下:

@Bean
@ConditionalOnMissingBean
public BeansEndpoint beansEndpoint() {
    return new BeansEndpoint();
}

 

@Bean –> 注册1个id为 beansEndpoint,类型为BeansEndpoint的bean
@ConditionalOnMissingBean–> 当beanFactory中不存在BeansEndpoint类型的bean时生效

ConfigurationPropertiesReportEndpoint

做用:–>暴露被@ConfigurationProperties 注解的bean的属性.为了保护数据,将敏感数据进行了脱敏

字段:

private static final String CONFIGURATION_PROPERTIES_FILTER_ID = "configurationPropertiesFilter";

// 数据脱敏
private final Sanitizer sanitizer = new Sanitizer();

// 经过实现ApplicationContextAware 进行自动注入
private ApplicationContext context;

public ConfigurationPropertiesReportEndpoint() {
    super("configprops");
}

invoke 实现:

public Map<String, Object> invoke() {
return extract(this.context);
}

 

调用:

protected Map<String, Object> extract(ApplicationContext context) {
    // Serialize beans into map structure and sanitize values
    ObjectMapper mapper = new ObjectMapper();
    // 1. 配置ObjectMapper的属性
    configureObjectMapper(mapper);
    // 2. 抽取数据
    return extract(context, mapper);
}

 

对ObjectMapper 进行配置:

代码以下:

    protected void configureObjectMapper(ObjectMapper mapper) {
        mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
        applyConfigurationPropertiesFilter(mapper);
        applySerializationModifier(mapper);
    }

 

SerializationFeature.FAIL_ON_EMPTY_BEANS –> 设置当对于给定的类型没法访问时如何处理,true–> 抛出异常,false–> 返回null
SerializationFeature.WRITE_NULL_MAP_VALUES –> 设置当map对于的value为null时如何处理,treu–>序列化,false–> 跳过

applyConfigurationPropertiesFilter 代码以下:

    private void applyConfigurationPropertiesFilter(ObjectMapper mapper) {
        mapper.setAnnotationIntrospector(
                new ConfigurationPropertiesAnnotationIntrospector());
        mapper.setFilterProvider(new SimpleFilterProvider()
                .setDefaultFilter(new ConfigurationPropertiesPropertyFilter()));
    }

 

设置AnnotationIntrospector为ConfigurationPropertiesAnnotationIntrospector.该类的做用是:得到@JsonFilter注解的值,若是获取不到,则返回configurationPropertiesFilter.代码以下:

private static class ConfigurationPropertiesAnnotationIntrospector
extends JacksonAnnotationIntrospector {
    @Override
    public Object findFilterId(Annotated a) {
        // 1. 得到@JsonFilter注解的值,若是获取不到,则返回    configurationPropertiesFilter
        Object id = super.findFilterId(a);
        if (id == null) {
            id = CONFIGURATION_PROPERTIES_FILTER_ID;
        }
        return id;
    }
}

 

设置默认的过滤器为ConfigurationPropertiesPropertyFilter,该类的做用是进行以下规则的过滤:
类名以$$开头的被过滤掉
自我引用的字段被过滤掉
当在序列化时抛出异常时过滤掉

代码以下:

public void serializeAsField(Object pojo, JsonGenerator jgen,
SerializerProvider provider, PropertyWriter writer) throws Exception {
if (writer instanceof BeanPropertyWriter) {
try {
// 1. 自我引用的字段被过滤掉
if (pojo == ((BeanPropertyWriter) writer).get(pojo)) {
if (logger.isDebugEnabled()) {
logger.debug("Skipping '" + writer.getFullName() + "' on '"
+ pojo.getClass().getName()
+ "' as it is self-referential");
}
return;
}
}
catch (Exception ex) {
// 2. 当在序列化时抛出异常时过滤掉
if (logger.isDebugEnabled()) {
logger.debug("Skipping '" + writer.getFullName() + "' on '"
+ pojo.getClass().getName() + "' as an exception "
+ "was thrown when retrieving its value", ex);
}
return;
}
}
// 3. 序列化字段
super.serializeAsField(pojo, jgen, provider, writer);
}

 

设置序列化工厂中的方法序列化器为GenericSerializerModifier.代码以下:

public List<BeanPropertyWriter> changeProperties(SerializationConfig config,
BeanDescription beanDesc, List<BeanPropertyWriter> beanProperties) {
List<BeanPropertyWriter> result = new ArrayList<BeanPropertyWriter>();
for (BeanPropertyWriter writer : beanProperties) {
boolean readable = isReadable(beanDesc, writer);
if (readable) {
result.add(writer);
}
}
return result;
}

 

依次遍历beanProperties,若是可读的话,则添加至result中.可读的判断逻辑以下:
根据bean 的类型和属性的类型 找出对应的set方法
若是set方法 存在或者是同一包下的类或者是map或者集合的子类,则返回true

调用extract方法抽取数据.代码以下:

private Map<String, Object> extract(ApplicationContext context, ObjectMapper mapper) {
Map<String, Object> result = new HashMap<String, Object>();
// 1. 得到beanFactory中ConfigurationBeanFactoryMetaData类型的bean
ConfigurationBeanFactoryMetaData beanFactoryMetaData = getBeanFactoryMetaData(
context);
// 2. 得到被@ConfigurationProperties注解的bean，key--> bean的id,value --> bean
Map<String, Object> beans = getConfigurationPropertiesBeans(context,
beanFactoryMetaData);
// 3. 依次遍历beans
for (Map.Entry<String, Object> entry : beans.entrySet()) {
String beanName = entry.getKey();
Object bean = entry.getValue();
Map<String, Object> root = new HashMap<String, Object>();
String prefix = extractPrefix(context, beanFactoryMetaData, beanName, bean);
// 3.1 得到@ConfigurationProperties注解的前缀,添加至root中,key-->prefix,value-->@ConfigurationProperties注解的前缀
root.put("prefix", prefix);
// 3.2 
root.put("properties", sanitize(prefix, safeSerialize(mapper, bean, prefix)));
// 3.3 添加至result中,key--> bean id,value-->map{prefix=xx,properties=xx}
result.put(beanName, root);
}
// 4. 若是ApplicationContext存在父容器的,则递归调用extract提取数据,key为parent.
if (context.getParent() != null) {
result.put("parent", extract(context.getParent(), mapper));
}
return result;
}

 

得到beanFactory中ConfigurationBeanFactoryMetaData类型的bean
得到被@ConfigurationProperties注解的bean，key–> bean的id,value –> bean

依次遍历beans
得到@ConfigurationProperties注解的前缀,添加至root中,key–>prefix,value–>@ConfigurationProperties注解的前缀

对数据进行脱敏.代码以下:

private Map<String, Object> sanitize(String prefix, Map<String, Object> map) {
for (Map.Entry<String, Object> entry : map.entrySet()) {
String key = entry.getKey();
String qualifiedKey = (prefix.isEmpty() ? prefix : prefix + ".") + key;
Object value = entry.getValue();
if (value instanceof Map) {
// 1. 若是对应的属性值为Map,List 则递归调用sanitize 进行数据脱敏
map.put(key, sanitize(qualifiedKey, (Map<String, Object>) value));
}
else if (value instanceof List) {
map.put(key, sanitize(qualifiedKey, (List<Object>) value));
}
else {
// 2. 若是属性名包含password", "secret", "key", "token", ".*credentials.*", "vcap_services,则将其替换为******
value = this.sanitizer.sanitize(key, value);
value = this.sanitizer.sanitize(qualifiedKey, value);
map.put(key, value);
}
}
return map;
}

 

若是对应的属性值为Map,List 则递归调用sanitize 进行数据脱敏
不然若是属性名包含password, secret, key, token, .*credentials.*, vcap_services,则将其替换为**
添加至result中,key–> bean id,value–>map{prefix=xx,properties=xx}

若是ApplicationContext存在父容器的,则递归调用extract提取数据,key为parent.

因为ConfigurationPropertiesReportEndpoint 被@ConfigurationProperties(prefix = “endpoints.configprops”)注解,所以可经过以下属性配置:

endpoints.configprops.id=configprops 
endpoints.configprops.sensitive=true 
endpoints.configprops.enabled=true 
endpoints.configprops.keys-to-sanitize=password,secret

之因此能够经过 endpoints.configprops.keys-to-sanitize 进行配置,是由于ConfigurationPropertiesReportEndpoint声明了以下方法:

public void setKeysToSanitize(String... keysToSanitize) {
this.sanitizer.setKeysToSanitize(keysToSanitize);
}

自动化配置(在EndpointAutoConfiguration中配置):

代码以下:

@Bean
@ConditionalOnMissingBean
public ConfigurationPropertiesReportEndpoint configurationPropertiesReportEndpoint() {
return new ConfigurationPropertiesReportEndpoint();
}

 

@Bean –> 注册1个id为configurationPropertiesReportEndpoint,类型为ConfigurationPropertiesReportEndpoint的Bean
@ConditionalOnMissingBean –> beanFactory中不存在ConfigurationPropertiesReportEndpoint类型的bean时生效

TraceEndpoint

做用:–> 该端点用来返回基本的HTTP跟踪信息。默认状况下，跟踪信息的存储采用org.springframework.boot.actuate.trace.InMemoryTraceRepository实现的内存方式，始终保留最近的100条请求记录.其中,返回的Trace定义以下:

public final class Trace {

// 时间戳
private final Date timestamp;

// 保存用于分析上下文信息，例如HTTP头
private final Map<String, Object> info;

public Trace(Date timestamp, Map<String, Object> info) {
super();
Assert.notNull(timestamp, "Timestamp must not be null");
Assert.notNull(info, "Info must not be null");
this.timestamp = timestamp;
this.info = info;
}

public Date getTimestamp() {
return this.timestamp;
}

public Map<String, Object> getInfo() {
return this.info;
}
}

 

字段:

private final TraceRepository repository;

这里咱们有必要说明一下TraceRepository:

TraceRepository 是用来保存Trace的. 接口定义以下:

public interface TraceRepository {

// 返回保存的Trace
List<Trace> findAll();

// 进行添加
void add(Map<String, Object> traceInfo);
}

TraceRepository 只要1个实现–>InMemoryTraceRepository.其字段以下:

// 容量为100
private int capacity = 100;
// 是否倒序展现,默认为false
private boolean reverse = true;
// 容器,用于保存Trace
private final List<Trace> traces = new LinkedList<Trace>();

findAll只需简单的返回保存的traces便可.实现以下:

public List<Trace> findAll() {
synchronized (this.traces) {
return Collections.unmodifiableList(new ArrayList<Trace>(this.traces));
}
}

add,代码以下:

public void add(Map<String, Object> map) {
// 1. 实例化Trace,时间戳为当前时间
Trace trace = new Trace(new Date(), map);
synchronized (this.traces) {
// 2. 若是traces中的容量大于等于了阈值,则进行删除.若是reverse等于true 则删除最后1个,不然,删除第1个
while (this.traces.size() >= this.capacity) {
this.traces.remove(this.reverse ? this.capacity - 1 : 0);
}
// 3. 进行添加,若是reverse等于true 则添加至第1个,不然,添加至最后
if (this.reverse) {
this.traces.add(0, trace);
}
else {
this.traces.add(trace);
}
}
}

实例化Trace,时间戳为当前时间
若是traces中的容量大于等于了阈值,则进行删除.若是reverse等于true 则删除最后1个,不然,删除第1个
进行添加,若是reverse等于true 则添加至第1个,不然,添加至最后

TraceRepository 是在何处配置的呢?

在TraceRepositoryAutoConfiguration中,代码以下:

@ConditionalOnMissingBean(TraceRepository.class)
@Bean
public InMemoryTraceRepository traceRepository() {
return new InMemoryTraceRepository();
}

@Bean –> 注册1个id为traceRepository,类型为InMemoryTraceRepository的bean
@ConditionalOnMissingBean(TraceRepository.class)–> 当beanFactory中不存在TraceRepository类型的bean时生效

invoke 实现:

@Override
public List<Trace> invoke() {
return this.repository.findAll();
}

只需调用TraceRepository# findAll,返回保存的Trace便可.

属性配置,所以其被@ConfigurationProperties(prefix = “endpoints.trace”)注解,所以能够经过以下属性进行配置:

endpoints.trace.id=trace
endpoints.trace.sensitive=true
endpoints.trace.enabled=true

自动装配:

在EndpointAutoConfiguration中进行了装配,代码以下:

@Bean
@ConditionalOnMissingBean
public TraceEndpoint traceEndpoint() {
return new TraceEndpoint(this.traceRepository == null
? new InMemoryTraceRepository() : this.traceRepository);
}

@Bean–> 注册1个id为traceEndpoint,类型为TraceEndpoint的bean
@ConditionalOnMissingBean–> 当beanFactory中不存在TraceEndpoint类型的bean时生效

这里提1个问题,TraceEndpoint 是经过TraceRepository获取Trace,那么TraceRepository中的Trace是如何保存的呢?

答案:

经过WebRequestTraceFilter(Filter)来实现. WebRequestTraceFilter实现了Ordered接口,指定了其在过滤器链中的顺序,代码以下:

private int order = Ordered.LOWEST_PRECEDENCE - 10;

public int getOrder() {
return this.order;
}

WebRequestTraceFilter中的字段以下:

private static final Log logger = LogFactory.getLog(WebRequestTraceFilter.class);

// debug时使用.若是启用的话,而且log的trace级别可用的话,则打印请求头信息,默认为false
private boolean dumpRequests = false;

// Not LOWEST_PRECEDENCE, but near the end, so it has a good chance of catching all
// enriched headers, but users can add stuff after this if they want to
private int order = Ordered.LOWEST_PRECEDENCE - 10;

private final TraceRepository repository;

private ErrorAttributes errorAttributes;

private final TraceProperties properties;

其中TraceProperties的定义以下:

@ConfigurationProperties(prefix = "management.trace")
public class TraceProperties {

private static final Set<Include> DEFAULT_INCLUDES;

static {
Set<Include> defaultIncludes = new LinkedHashSet<Include>();
defaultIncludes.add(Include.REQUEST_HEADERS);
defaultIncludes.add(Include.RESPONSE_HEADERS);
defaultIncludes.add(Include.COOKIES);
defaultIncludes.add(Include.ERRORS);
defaultIncludes.add(Include.TIME_TAKEN);
DEFAULT_INCLUDES = Collections.unmodifiableSet(defaultIncludes);
}

private Set<Include> include = new HashSet<Include>(DEFAULT_INCLUDES);

public Set<Include> getInclude() {
return this.include;
}

public void setInclude(Set<Include> include) {
this.include = include;
}
}

默认配置的是Include.REQUEST_HEADERS, Include.RESPONSE_HEADERS, Include.COOKIES ,Include.ERRORS, Include.TIME_TAKEN. 能够经过以下进行配置

management.trace.include=REQUEST_HEADERS,RESPONSE_HEADERS
1

可选值为org.springframework.boot.actuate.trace.TraceProperties.Include.这里就不在贴出了

WebRequestTraceFilter 继承了OncePerRequestFilter,所以只需实现doFilterInternal便可,代码以下：

protected void doFilterInternal(HttpServletRequest request,
HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
long startTime = System.nanoTime();
// 1. 得到trace
Map<String, Object> trace = getTrace(request);
// 2. 打印日志-->若是log的trace级别可用的话而且dumpRequests等于true,则打印请求头信息,默认为false
logTrace(request, trace);
int status = HttpStatus.INTERNAL_SERVER_ERROR.value();
try {
// 3. 继续过滤器链的过滤,最后得到响应状态
filterChain.doFilter(request, response);
status = response.getStatus();
}
finally {
// 4. 添加Http请求耗时统计-->若是TraceProperties中配置了Include#TIME_TAKEN(默认配置了),则添加到trace中,key为timeTaken，value-->当前时间-开始时间的毫秒值
addTimeTaken(trace, startTime);
// 5. 添加响应头信息
enhanceTrace(trace, status == response.getStatus() ? response
: new CustomStatusResponseWrapper(response, status));
// 6. 添加至TraceRepository 中
this.repository.add(trace);
}
}

记录开始时间

得到trace.代码以下:

protected Map<String, Object> getTrace(HttpServletRequest request) {
// 1. 得到HttpSession
HttpSession session = request.getSession(false);
// 2. 得到javax.servlet.error.exception,所对应的异常--> 当spring mvc 出现异常时,会加入到javax.servlet.error.exception中
Throwable exception = (Throwable) request
.getAttribute("javax.servlet.error.exception");
// 3. 得到Principal,若是返回null,说明没有该请求没有进行验证
Principal userPrincipal = request.getUserPrincipal();
Map<String, Object> trace = new LinkedHashMap<String, Object>();
Map<String, Object> headers = new LinkedHashMap<String, Object>();
// 4. 添加请求方法,请求路径,请求头到trace中
trace.put("method", request.getMethod());
trace.put("path", request.getRequestURI());
trace.put("headers", headers);
if (isIncluded(Include.REQUEST_HEADERS)) {
headers.put("request", getRequestHeaders(request));
}
// 省略掉默认不执行的代码....
// 5. 若是有异常而且errorAttributes不等于null,则记录error
if (isIncluded(Include.ERRORS) && exception != null
&& this.errorAttributes != null) {
trace.put("error", this.errorAttributes
.getErrorAttributes(new ServletRequestAttributes(request), true));
}
return trace;
}

继续过滤器链的过滤,最后得到响应状态

添加Http请求耗时统计–>若是TraceProperties中配置了Include#TIME_TAKEN(默认配置了),则添加到trace中,key为timeTaken，value–>当前时间-开始时间的毫秒值.代码以下:

private void addTimeTaken(Map<String, Object> trace, long startTime) {
long timeTaken = System.nanoTime() - startTime;
add(trace, Include.TIME_TAKEN, "timeTaken",
"" + TimeUnit.NANOSECONDS.toMillis(timeTaken));
}

添加响应头信息.代码以下:

protected void enhanceTrace(Map<String, Object> trace, HttpServletResponse response) {
if (isIncluded(Include.RESPONSE_HEADERS)) {
Map<String, Object> headers = (Map<String, Object>) trace.get("headers");
headers.put("response", getResponseHeaders(response));
}
}

getResponseHeaders 代码以下:

private Map<String, String> getResponseHeaders(HttpServletResponse response) {
Map<String, String> headers = new LinkedHashMap<String, String>();
// 1. 依次遍历响应头,添加至headers 中,key--> 响应头名,value-->响应头对应的值
for (String header : response.getHeaderNames()) {
String value = response.getHeader(header);
headers.put(header, value);
}
// 2. 若是TraceProperties中没有配置Include#COOKIES,则在headers中删除key为Set-Cookie的值.默认是配置了的,所以不会删除
if (!isIncluded(Include.COOKIES)) {
headers.remove("Set-Cookie");
}
// 3. 向headers 中添加 key--> status,value-->响应状态码
headers.put("status", "" + response.getStatus());
return headers;
}

遍历响应头,添加至headers 中,key–> 响应头名,value–>响应头对应的值
若是TraceProperties中没有配置Include#COOKIES,则在headers中删除key为Set-Cookie的值.默认是配置了的,所以不会删除
向headers 中添加 key–> status,value–>响应状态码
添加至TraceRepository中

WebRequestTraceFilter 是如何配置的呢?

答案: 在TraceWebFilterAutoConfiguration中.代码以下:

@Bean
@ConditionalOnMissingBean
public WebRequestTraceFilter webRequestLoggingFilter(BeanFactory beanFactory) {
WebRequestTraceFilter filter = new WebRequestTraceFilter(this.traceRepository,
this.traceProperties);
if (this.errorAttributes != null) {
filter.setErrorAttributes(this.errorAttributes);
}
return filter;
}

@Bean–> 注册1个id为webRequestLoggingFilter,类型为WebRequestTraceFilter的bean
@ConditionalOnMissingBean–> 当beanFactory中不存在WebRequestTraceFilter类型的bean时生效

同时因为TraceWebFilterAutoConfiguration声明了以下注解:

@Configuration
@ConditionalOnClass({ Servlet.class, DispatcherServlet.class, ServletRegistration.class })
@AutoConfigureAfter(TraceRepositoryAutoConfiguration.class)
@ConditionalOnProperty(prefix = "endpoints.trace.filter", name = "enabled", matchIfMissing = true)
@EnableConfigurationProperties(TraceProperties.class)

@Configuration–> 配置类 @ConditionalOnClass({ Servlet.class, DispatcherServlet.class, ServletRegistration.class })–> 在当前的类路径下存在Servlet.class, DispatcherServlet.class, ServletRegistration.class时生效 @AutoConfigureAfter(TraceRepositoryAutoConfiguration.class)–> 在TraceRepositoryAutoConfiguration以后进行自动装配,这样就能够自动注入TraceRepository @ConditionalOnProperty(prefix = “endpoints.trace.filter”, name = “enabled”, matchIfMissing = true)–> 当配置有endpoints.trace.filter.enabled 等于true时生效,若是没有配置,默认生效 @EnableConfigurationProperties(TraceProperties.class)–> 能够经过management.trace.include 进行配置.转：https://blog.csdn.net/qq_26000415/article/details/79060258