Spring Boot 项目健康检查工具Actuator

前言

公司经过野蛮生长阶段，系统稳定性，CI，CD持续集成交付，基于Spring Cloud 微服务系统使用Spring Boot健康检查工具，提高发布的效率和全方位监控。在没有监控之前，比如说一个Feign微服务项目，我们可能在SpringBoot项目启动之后通过一个Rest接口比如说 127.0.0.1:8888/ok 这个种接口的形式，集成在自动化脚本里面去校验发布时候正常，或者人工去做一些校验。

其实这些都可以通过 Actuator 工具包去做。

官方文档： docs.spring.io/spring-boot…

Actuator 使用

在Spring boot应用中，要实现可监控的功能，依赖的是 spring-boot-starter-actuator 这个组件。它提供了很多监控和管理你的spring boot应用的HTTP或者JMX端点，并且你可以有选择地开启和关闭部分功能。当你的spring boot应用中引入下面的依赖之后，将自动的拥有审计、健康检查、Metrics监控功能。

添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
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创建一个spring web工程

初始化工程的时候勾选一些常用的工具类，比如lombok和actuator

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

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>
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检查点

应用启动了我们可以检查暴露的端口，通过http://localhost:8080/actuator来展示所有通过HTTP暴露的endpoints。
打开http://localhost:8080/actuator/health {"status":"UP"} 表示系统健康。

ID	Description
`auditevents`	Exposes audit events information for the current application. Requires an `AuditEventRepository` bean.
`beans`	Displays a complete list of all the Spring beans in your application.
`caches`	Exposes available caches.
`conditions`	Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match.
`configprops`	Displays a collated list of all `@ConfigurationProperties`.
`env`	Exposes properties from Spring’s `ConfigurableEnvironment`.
`flyway`	Shows any Flyway database migrations that have been applied. Requires one or more `Flyway` beans.
`health`	Shows application health information.
`httptrace`	Displays HTTP trace information (by default, the last 100 HTTP request-response exchanges). Requires an `HttpTraceRepository` bean.
`info`	Displays arbitrary application info.
`integrationgraph`	Shows the Spring Integration graph. Requires a dependency on `spring-integration-core`.
`loggers`	Shows and modifies the configuration of loggers in the application.
`liquibase`	Shows any Liquibase database migrations that have been applied. Requires one or more `Liquibase` beans.
`metrics`	Shows ‘metrics’ information for the current application.
`mappings`	Displays a collated list of all `@RequestMapping` paths.
`quartz`	Shows information about Quartz Scheduler jobs.
`scheduledtasks`	Displays the scheduled tasks in your application.
`sessions`	Allows retrieval and deletion of user sessions from a Spring Session-backed session store. Requires a Servlet-based web application using Spring Session.
`shutdown`	Lets the application be gracefully shutdown. Disabled by default.
`startup`	Shows the startup steps data collected by the `ApplicationStartup`. Requires the `SpringApplication` to be configured with a `BufferingApplicationStartup`.
`threaddump`	Performs a thread dump.

自定义健康指标

可以通过实现HealthIndicator接口来自定义一个健康指标，或者继承AbstractHealthIndicator类。 application.properties 添加参数

management.endpoint.health.show-details=always
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@Component
public class MyHealthIndicator extends AbstractHealthIndicator {
    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        builder.up()
                .withDetail("app", "Alive and Kicking")
                .withDetail("error", "Nothing! I'm ok.");
    }
}
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