Spring Boot Actuator in detail

The Actuator provides additional features that can monitor and manage online applications using HTTP or JMX, including auditing, service health and metrics collection, which are accessed through endpoints. Each endpoint can be enabled, disabled and exposed via Http or JMX.

When dependencies are added to a project, Endpoints are automatically registered with the application as they become available and can be accessed via HTTP or JMX

Configuration and simple use

Begin to use

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

Start the project access /actuator/ Health and get the following

{"status":"UP"}
Copy the code

The/skeletonoid uses the default URL prefix to access endpoints, and /health displays the health information of applications.

You can modify the URL prefix of endpoints to change the health access address to /simple/health

management.endpoints.web.base-path=/simple
Copy the code

Because endpoints contain sensitive information, you should be careful when exposing endpoints. Common Endpoints and default exposures are listed below

ID	describe	JMX	Web
health	Applying health Information	YES	YES
info	Arbitrary application information	YES	NO
beans	Show all beans information in the application	YES	NO
env	The ConfigurableEnvironment in Spring exposes the attribute	YES	NO
metrics	Application metrics	YES	NO
headdump	Get the hprof dump file	N/A	NO
loggers	Displays and modifies application logging configurations	YES	NO

You can choose to expose and filter undesired Endpoints by using the following command

Property	Default
management.endpoints.jmx.exposure.exclude
management.endpoints.jmx.exposure.include	*
management.endpoints.web.exposure.exclude
management.endpoints.web.exposure.include	The health, the info

Enabling and disabling the endpoint


      
       . Enabled to enable shutdown endpoint
      
All endpoints except shutdown are enabled by default
management:
  endpoint:
    shutdown:
      enabled: true
Copy the code

Expose and filter unwanted endpoints

management:
  endpoints:
    web:
      exposure:
        Use HTTP to access /actuator/health, /actuator/beans, and /actuator/info
        include: health,info,beans
        Info endpoint is not accessible through HTTP
        exclude: info
Copy the code

If include and exclude are used together, exclude takes precedence, so info is not accessible through HTTP

Custom Endpoint

Create the Bean, add an annotation @endpoint, @webendpoint, @endPointwebextension to the class, and add @readOperation or @writeOperation or @deleteOperation to the method. For web applications, the endpoint can be exposed via HTTP using Jersey, SpringMVC, Spring WebFlux, or SpingMVC if both Jersey and SpingMVC are available.

@ServleTendPoint and @Controllerendpoint can also be used, but @endpoint and @webendpoint are recommended

Here we use @endpoint as an example, and refer to the complete demo code provided for the rest

The @endpoint ID property must be set
```
@Configuration
//id must be set
@Endpoint(id = "myCustomEndpoints")
public class MyCustomEndpoints {
    @ReadOperation
    public ShopData getData(a){
        return new ShopData("Shop girl"."Global Village");
    }
    @Data
    @AllArgsConstructor
    public static class ShopData{
        private String name;
        privateString address; }}Copy the code
```
```
management:
  endpoints:
    web:
      exposure:
      # # myCustomEndpoints exposure
        include: health,info,beans,env,myCustomEndpoints
Copy the code
```
Access: physical/myCustomEndpoints returns the {” name “:” the bartender “, “address” : “global village”}

Common Endpoint details

Health endpoint

You can use the health indicator to determine the health status of an application. You can view detailed health information through the following property configuration

There are only three options: nerver, When – Authorized, always default micro nerver

If show-components is not specified, show-details will be displayed with the value
# if show-components is specified, the configuration of show-components will prevail
management.endpoint.health.show-details=always
management.endpoint.health.show-components=always
Copy the code

Springboot comes with some common health metrics (listed only in a few)

DataSourceHealthIndicator: check the database connection status
DiskSpaceHealthIndicator: Checks whether the disk space is insufficient
ElasticsearchRestHealthIndicator: check ES cluster is up
Mail: Check whether the email server is in up state
Rabbit: Check whether the RabbitMQ server is in the Up state
Redis: Check whether redis is in up state

Customize health indicators

/** * Verify that the value of custom.url is correct, if it is correct, the state is up, if not, it is down */
@Component
public class MyCustomIndicator implements HealthIndicator {

    @Value("${custom.url}")
    private String customUrl;

    @Override
    public Health health(a) {
        if("http://www.baidu.com".equalsIgnoreCase(customUrl)){
            return Health.up().build();
        }
        return Health.down().withDetail("customUrl",customUrl).build(); }}Copy the code

custom.url = http://www.baidu.com
Copy the code

{"status":"UP"."components": {"diskSpace": {"status":"UP"."details": {"total":250685575168."free":46600232960."threshold":10485760."exists":true}},"myCustomIndicator": {"status":"UP"},"ping": {"status":"UP"}}}
Copy the code

Custom.url is incorrectly configured. The result is as follows:

custom.url = http://www.baidu.com001
Copy the code

{"status":"DOWN"."components": {"diskSpace": {"status":"UP"."details": {"total":250685575168."free":46598496256."threshold":10485760."exists":true}},"myCustomIndicator": {"status":"DOWN"."details": {"customUrl":"http://www.baidu.com001"}},"ping": {"status":"UP"}}}
Copy the code

info endpoint

SpringBoot includes many auto-configured InfoContributor features listed below are a few commonly used ones

The information in the EnvironmentInfoContributor public Environment
GitInfoContributor exposes git information if the git.properties file is available
BuildInfoContributor public build information if META/INF/build-info.properties is available

Customize Application Information

# Customize the data exposed by ifO endpoints by setting the info.* Spring attribute
info.app.encoding = UTF-8
#info.app.java.source = 8
info.app.java.source = @java.version@
Copy the code

The running results are as follows:

{"app": {"encoding":"UTF-8"."java": {"source":"1.8.0 comes with _191"}}}
Copy the code

Obtain build info if necessary

<build>
  <plugins>
    <plugin>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-maven-plugin</artifactId>
      <executions>
        <execution>
          <goals>
            <goal>build-info</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>
Copy the code

Then run the result as follows

{"app": {"encoding":"UTF-8"."java": {"source":"1.8.0 comes with _191"}},"build": {"version":"1.0 the SNAPSHOT"."artifact":"actuator-simple"."name":"actuator-simple"."group":"com.hs.springboot"."time":"The 2021-06-04 T02:51:53. 878 z"}}
Copy the code

Loggers endpoint

Use the /actuator/loggers command to view and modify the log level of an application. You can use them to view all log levels

{"levels": ["OFF"."ERROR"."WARN"."INFO"."DEBUG"."TRACE"]."loggers": {"ROOT": {"configuredLevel":"INFO"."effectiveLevel":"INFO"},"com": {"configuredLevel":null."effectiveLevel":"INFO"},"com.hs": {"configuredLevel":null."effectiveLevel":"INFO"},"com.hs.springboot": {"configuredLevel":null."effectiveLevel":"INFO"},"com.hs.springboot.actuator": {"configuredLevel":null."effectiveLevel":"INFO"},"com.hs.springboot.actuator.ActuatorSimpleApplication": {"configuredLevel":null."effectiveLevel":"INFO"},"io": {"configuredLevel":null."effectiveLevel":"INFO"},"io.micrometer":
Copy the code

If you want to access a specific log configuration, for example, that of ROOT, the access path is as follows: /actuator/loggers/ROOT

EffectiveLevel and configuredLevel are the same if configuredLevel is configured. If configuredLevel is not displayed, the configuredLevel is null
{"configuredLevel":"INFO"."effectiveLevel":"INFO"}
Copy the code

Modify the ROOT log level request path /actuator/loggers/ROOT Dynamically adjust the log level parameters of the application as follows:

{
    "configuredLevel": "DEBUG"
}
Copy the code

Conclusion:

The Operating Actuator can view status information of applications and customize health checks that meet its own requirements

System integration with monitoring software such as Prometheus (integration with Prometheus later)

Full code address

References:

Spring Boot Actuator

Spring Boot Actuator Web API

Configuration and simple use

Begin to use

Enabling and disabling the endpoint

Expose and filter unwanted endpoints

Custom Endpoint

Common Endpoint details

Related Posts

Here’s what you need to know about ThreadLocal

SpringCloudAlibaba Dubbo summary | of the August more challenges

Java byte streams and character streams, it’s time to summarize IO streams