SpringBoot应用监控解析：Actuator实现原理

<dependency>
<groupId>org. springframework . boot</groupId>
<artifactId>spring- boot -starter-actuator</artifactId>
</ dependency>

<dependency>
<groupId>org. springframework . boot</groupId>
<artifactId>spring- boot- actuator</ artifactId>
</ dependency>
<dependency>
<groupId>org. springfr amework . boot</ groupId>
<artifactId>spring- boot- actuator autoconfigure</ artifactId>
</ dependency>

{
_links":
"self": {
"href": "http://localhost: 8080/actuator",
"templated": false
}，
"health-path": {
"href": "http://localhost: 8080/ actuator/health/{*path}"，
"templated": true
"health": {
"href": "http://localhost :8080/ actuator/health" ,"templated": false
}，
"info": {
"href": "http://localhost : 8080/actuator/info",
"templated": false
}
}
}

#启用 shutdown
management . endpoint . shutdown. enabled=true
#全部禁用
management . endpoints . enabled-by-default=false
s 启用 info
management . endpoint. info. enabled=true

@Configuration(proxyBeanMethods = false)@ConditionalOnAvailableEndpoint (endpoint = HealthEndpoint . class)
@EnableConfigurationProperties
@Import({ LegacyHealthEndpointAdaptersConfiguration. class, LegacyHealthEndpoint-
CompatibilityConfiguration. class,
HealthEndpointConfiguration. class, ReactiveHealthEndpointConfiguration. class,
HealthEndpointWebExtens ionConfiguration. class, HealthEndpointReactive-
WebExtens ionConfiguration.class })
public class HealthEndpointAutoConfiguration {
@Bean
@SuppressWarnings("deprecation")
HealthEndpointProperties healthEndpointProperties (HealthIndicatorProperti
es healthIndicatorPrope
rties) {
HealthEndpointProperties healthEndpointProperties = new HealthEndpoint -
Properties();
healthEndpointProperties . getStatus(). getOrder(). addAll(healthIndicator-
Properties . get0r
der());
healthEndpointProperties . getStatus(). getHttpMapping() . putAll(healthIn-
dicatorPro
perties . getHttpMapping());
return healthEndpointProperties;
}
}

@Configurat ion(proxyBeanMethods = false)d.5)
class HealthEndpointConfi guratior
//实例化 StatusAggregator, heal th 状态聚合器
@Bean
@ConditionalOnMissingBean
StatusAggregator healthStatusAggregator(HealthEndpointProperties properti
es
//默认采用其 SimpleStatusAggregator 实现，如果未指定 status,则默认集合 Stat
us 类中定义的所有状态集合
return new SimpleStatusAggregator(properties . getStatus(). get0rder());
//实例 fCHttpCodeStatusMapper, 用于映射 Heal th.到 Http 的状态码
@Bean
@Condit ionalOnMissingBean
HttpCodeStatusMapper healthHttpCodeStatusMapper(HealthEndpointProperties
F_ SERVICE 到 HTTP 的 503
odestatuSMapper 买现，
映射 Status . DOWN 和 Status.OUT 0
return new SimpleHttpCodeStatusMapper(properties . getStatus() . getHttpMap
ping());
//实例 CHeal thEndpointGroups,用 FHeal thEndpointGroup 的集合操作
@Bear
@ConditionalOnMissingBean
HealthEndpointGroups healthEndpointGroups(ApplicationContext applicationC
ontext,
HealthEndpointProperties prope
rties) {
采用 AutoConfiguredHeal thEndpointGroups 实现，该类主要没置其属性 primaryroup
return new AutoConfiguredHealthEndpointGroups ( applicat ionContext, properties);
// 实 例 CHeal thContributorRegistry, 用 FHeal thContributor 的 可 变 注 册@ConditionalOnMissingBean
HealthContributorRegi stry
plicationContext,
HealthEndpointGroups
groups) {
Map<String, HealthContributor> healthContributors = new LinkedHashMap<>
applicationContext. getBeansOfType(HealthContributor . class));
// 如 果 类 路 径 下 存 在 reactor. core . publ isher. Flux 类 ， 则 添 力 Reactive 相 关 的
AdaptedReact-
iveHealthContributors
if (ClassUtils. isPresent( "reactor . core . publisher. Flux"，applicationCont
ext.
getClassLoader())) {
healthContributors. putAll(new AdaptedReactiveHealthContributors(ap-
plica
tionContext).get());
//采用 HealthContributorRegistry 实现类，磅保注册的注册器不与 group 的名字冲
return new AutoConf iguredHealthContributorRegistry(healthContributors，
groups . getNames());
//实例化 Heal thEndpoint,用户暴露应用程序的健康信息
@Bear
@Condit ionalOnMissingBean
HealthEndpoint healthEndpoint(Heal thContr ibutorRegistry registry, HealthE
ndpoint
Groups groups) {
return new HealthEndpoint(registry, groups);
省略内部类 AdaptedReactiveHeal thContributors 相关代码，用 FReactiveHea
l thContributor
的适配器
}

@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type . SERVLET)
@ConditionalonBean(HealthEndpoint. class)
class HealthEndpointWebExtensionConfiguration {
@Bean
@ConditionalOnBean(HealthEndpoint. class)
@ConditionalOnMissingBean
HealthEndpointWebExtension healthEndpointWebExtension(HealthContri butorRe
g-
istry healthContrib
utorRegistry,
HealthEndpointGroup
s groups) {
return new HealthEndpointWebExtension(healthContributorRegistry, group
s);
}
}

@FunctionalInterface
public interface HealthIndicator extends HealthContributor {
//根据 includeDetails,返回 health 指示
default Health getHealth(boolean includeDetails) {
Health health = health();
//如果 includeDetails 为 true 则直接返@health,否则返 回不携带洋情的 health
return includeDetails ? health : health . withoutDetails();
//返回 health 指示
Health health();
}

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ JdbcTemplate. class, AbstractRoutingDataSource.class
})@ConditionalOnBean(DataSource. class)
@ConditionalOnEnabledHealthIndicator("db")
@AutoConfigureAfter (DataSourceAutoConfiguration. class)
public class DataSourceHealthContributorAutoConfiguration extends
CompositeHealthContributorConfiguration<AbstractHealthIndicator, DataSource>
implements InitializingBean {
//实例化 Heal thContributor
@Bean
@Condit ionalOnMissingBean(name = { "dbHealthIndicator", "dbHea lthContribu
tor" })
public HealthContributor dbHealthContributor(Map<String, DataSource> data
Sources) {
//主要通过 DataSource 数据源通过反射生成 Heal thContributor,
//这里通过父类 CompositeHeal thContributorConfigurat ion 的 createContributor
方法进行调用
// 当前类重写的 create Indicator 方法
return createContributor(dataSources);
//实例化对应的 AbstractHealthIndicator, 重 写父类 createIndicator 方法
@Override
protected AbstractHealthIndicator createIndicator(DataSource source) {
if (source instanceof AbstractRout ingDataSource) {
return new RoutingDataSourceHealthIndicator();
}
//实例化 DataSourceHealthIndicator, 参数数据源和查询语句
return new DataSourceHealthIndicator(source, getValidationQuery(sourc
e));
//获取检测所需的查询语句
private String getValidationQuery (DataSource source) {
//获取 DataSourcePooLMetadata 对象， 并 调用其 getVal idationQuery 方法
// getVal idationQuery 方法用来获得执行验证数据库链接是否正常的 SQL
DataSourcePoolMetadata poolMetadata = this . poolMetadataProvider . getDa-
taSourcePoolMetadata(source);
return (poolMetadata != null) ? poolMetadata. getValidationQuery() : null;
}。。。
}

public class DataSourceHealthIndicator extends AbstractHealthIndicator Q
implements InitializingBean {
private static final String DEFAULT QUERY = "SELECT 1";
private DataSource dataSource;
private String query;
private JdbcTemplate jdbcTemplate;
//监控检测的入口方法
@Override
protected void doHealthCheck(Health. Builder builder) throws Exception {
if (this .dataSource == null)
/如果数据源不存在，则返@unknown
builder . up().withDetail(" database", "unknown");
else {
//如果数据存在，则进行相应的检测操作
doDataSourceHealthCheck(builder);
private void doDataSourceHealthCheck(Health. Builder builder) throws Exception
//获取数据库名称
String product = getProduct();
builder. up() .withDetail("database", product);
//根据数据库名称获取对应的验证语句
String validationQuery = getValidationQuery(product);
if (StringUtils .hasText(validationQuery))
//避免在 Java 7 上破坏 MySQL 的情况下调用 getObject
//通过 jdbc Template 执行该 SQL 语句
List<Object> results = this . jdbcTemplate . query(validat ionQuery ,
new SingleColumnRowMapper());1 对查询结果进行处理
object result = DataAccessUtils . requiredSingleResult(results);
//结果存入 Health 中
builder .withDetail("hello", result);
//根据数据库名称获取对应的验证语句
protected String getValidationQuery(String product) {
String auery = this. auery:
if (!StringUtils. hasText(query)) {
//如果查询语句为指定，则根据数据库名称从枚举类 DatabaseDriver 中获取默认
的 sQL 语句
DatabaseDriver specific = DatabaseDriver . fromProductName( product);
query = specific . getValidat ionQuery();
if (!StringUtils. hasText(query)) {
i/如果以上情况都不存在， 则采用“SELECT 1”
query= DEFAULT OUERY:
query
return query;
}
}

public enum DatabaseDriver {
/ Unknown 类型
UNKNOWN(nul1, nu1l),
// Apache Derby.
DERBY("Apache Derby", "org. apache . derby . jdbc . EmbeddedDriver", "org. apach
e. derby. jdbc . EmbeddedXADataSource"，
"SELECT 1 FROM SYSIBM. SYSDUMMY1")，
// H2
H2("H2", "org.h2 .Driver", "org.h2. jdbcx. JdbcDataSource", "SELECT 1"),
// HyperSQL DataBase.
HSQLDB( "HSQL Database Engine", "org. hsq1db. jdbc. JDBCDriver", "org. hsqldb.jdbc . pool. JDBCXADataSource" ,
"SELECT COUNT(*) FROM INFORMATION_ SCHEMA. SYSTEM_ _USERS"),
// sQL Lite
SQLITE("SQLite", "org. sqlite .JDBC"),
// MySQL
MYSQL("MySQL", "com. mysql. cj . jdbc . Driver", "com. mysql . cj . jdbc . MysqlXAData
Source", "/* ping */ SELECT 1"),
// Oracle.
ORACLE("Oracle", "oracle. jdbc . OracleDriver", "oracle. jdbc.xa. client . Oracl
eXADataSource",
"SELECT 'Hello' from DUAL"), }

@Endpoint(id = "info")
public class InfoEndpoint {
@ReadOperationpublic Map<String, Object> info() {
Info. Builder builder = new Info . Builder();
for (InfoContributor contributor : this . infoContributors) {
contributor . contribute(builder);
Info build = builder . build( )
();
return build. getDetails();
}
}

@Endpoint(id = "health")
public class HealthEndpoint extends HealthEndpointSupport<HealthContributr, HealthComponent>
private static final String[] EMPTY_ PATH = {};
@ReadOperation
public HealthComponent health() {
HealthComponent health = health(ApiVersion.V3, EMPTY_ PATH);
return (health != null) ? health : DEFAULT_ HEALTH;
@ReadOperation
public HealthComponent healthForPath(@Selector(match = Match. ALL_ REMAIN
ING)
String... path) {
return health(ApiVersion.V3， path);
}
}

EndpointWebExtension(endpoint = Health
nEndpoint.class)
t. class)
public class HealthEndpointWebExtension extends HealthEndpointSupport<Healt
Contr
HealthComponent> {
@ReadOperation
public WebEndpointResponse<HealthComponent> health(ApiVersion apiVersion,
SecurityContext securi
tyContext) {
return health(apiVersion, securityContext, false, NO_ PATH);
@ReadOperation
public WebEndpointResponse<HealthComponent> health(ApiVersion apiVersion,
SecurityContext securi
tyContext,
@Selector(match = Matc
h.ALL REMAINING) String... path) {
return health(apiVersion, securityContext, false, path);} ....
}