49. Endpoints

Actuator endpoints let you monitor and interact with your application. Spring Boot includes a number of built-in endpoints and lets you add your own. For example, the health endpoint provides basic application health information.

Each individual endpoint can be enabled or disabled. This controls whether or not the endpoint is created and its bean exists in the application context. To be remotely accessible an endpoint also has to be exposed via JMX or HTTP. Most applications choose HTTP, where the ID of the endpoint along with a prefix of /actuator is mapped to a URL. For example, by default, the health endpoint is mapped to /actuator/health.

The following technology-agnostic endpoints are available:

IDDescriptionEnabled by default

auditevents

Exposes audit events information for the current application.

Yes

beans

Displays a complete list of all the Spring beans in your application.

Yes

conditions

Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match.

Yes

configprops

Displays a collated list of all @ConfigurationProperties.

Yes

env

Exposes properties from Spring’s ConfigurableEnvironment.

Yes

flyway

Shows any Flyway database migrations that have been applied.

Yes

health

Shows application health information.

Yes

httptrace

Displays HTTP trace information (by default, the last 100 HTTP request-response exchanges).

Yes

info

Displays arbitrary application info.

Yes

loggers

Shows and modifies the configuration of loggers in the application.

Yes

liquibase

Shows any Liquibase database migrations that have been applied.

Yes

metrics

Shows ‘metrics’ information for the current application.

Yes

mappings

Displays a collated list of all @RequestMapping paths.

Yes

scheduledtasks

Displays the scheduled tasks in your application.

Yes

sessions

Allows retrieval and deletion of user sessions from a Spring Session-backed session store. Not available when using Spring Session’s support for reactive web applications.

Yes

shutdown

Lets the application be gracefully shutdown.

No

threaddump

Performs a thread dump.

Yes

If your application is a web application (Spring MVC, Spring WebFlux, or Jersey), you can use the following additional endpoints:

IDDescriptionEnabled by default

heapdump

Returns a GZip compressed hprof heap dump file.

Yes

jolokia

Exposes JMX beans over HTTP (when Jolokia is on the classpath, not available for WebFlux).

Yes

logfile

Returns the contents of the logfile (if logging.file or logging.path properties have been set). Supports the use of the HTTP Range header to retrieve part of the log file’s content.

Yes

prometheus

Exposes metrics in a format that can be scraped by a Prometheus server.

Yes

To learn more about the Actuator’s endpoints and their request and response formats, please refer to the separate API documentation (HTML or PDF).

49.1 Enabling Endpoints

By default, all endpoints except for shutdown are enabled. To configure the enablement of an endpoint, use its management.endpoints.<id>.enabled property. The following example enables the shutdown endpoint:

management.endpoint.shutdown.enabled=true

If you prefer endpoint enablement to be opt-in rather than opt-out, set the management.endpoints.enabled-by-default property to false and use individual endpoint enabled properties to opt back in. The following example enables the info endpoint and disables all other endpoints:

management.endpoints.enabled-by-default=false
management.endpoint.info.enabled=true
[Note]Note

Disabled endpoints are removed entirely from the application context. If you want to change only the technologies over which an endpoint is exposed, use the expose and exclude properties instead.

49.2 Exposing Endpoints

Since Endpoints may contain sensitive information, careful consideration should be given about when to expose them. The following table shows the default exposure for the built-in endpoints:

IDJMXWeb

auditevents

Yes

No

beans

Yes

No

conditions

Yes

No

configprops

Yes

No

env

Yes

No

flyway

Yes

No

health

Yes

Yes

heapdump

N/A

No

httptrace

Yes

No

info

Yes

Yes

jolokia

N/A

No

logfile

N/A

No

loggers

Yes

No

liquibase

Yes

No

metrics

Yes

No

mappings

Yes

No

prometheus

N/A

No

scheduledtasks

Yes

No

sessions

Yes

No

shutdown

Yes

No

threaddump

Yes

No

To change which endpoints are exposed, use the following technology-specific expose and exclude properties:

PropertyDefault

management.endpoints.jmx.exclude

 

management.endpoints.jmx.expose

*

management.endpoints.web.exclude

 

management.endpoints.web.expose

info, health

The expose property lists the IDs of the endpoints that are exposed. The exclude property lists the IDs of the endpoints that should not be exposed. The exclude property takes precedence over the expose property.

For example, to stop exposing all endpoints over JMX and only expose the health endpoint, use the following property:

management.endpoints.jmx.expose=health

* can be used to select all endpoints. For example, to expose everything over HTTP except the env endpoint, use the following properties:

management.endpoints.web.expose=*
management.endpoints.web.exclude=env
[Note]Note

If your application is exposed publicly, we strongly recommend that you also secure your endpoints.

[Tip]Tip

If you want to implement your own strategy for when endpoints are exposed, you can register an EndpointFilter bean.

49.3 Securing HTTP Endpoints

You should take care to secure HTTP endpoints in the same way that you would any other sensitive URL. If Spring Security is present, endpoints are secured by default using Spring Security’s content-negotiation strategy. If you wish to configure custom security for HTTP endpoints, for example, only allow users with a certain role to access them, Spring Boot provides some convenient RequestMatcher objects that can be used in combination with Spring Security.

A typical Spring Security configuration might look something like the following example:

@Configuration
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {

	@Override
	protected void configure(HttpSecurity http) throws Exception {
		http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests()
				.anyRequest().hasRole("ENDPOINT_ADMIN")
				.and()
			.httpBasic();
	}

}

The preceding example uses EndpointRequest.toAnyEndpoint() to match a request to any endpoint and then ensures that all have the ENDPOINT_ADMIN role. Several other matcher methods are also available on EndpointRequest. See the API documentation (HTML or PDF) for details.

If you deploy applications behind a firewall, you may prefer that all your actuator endpoints can be accessed without requiring authentication. You can do so by changing the management.endpoints.web.expose property, as follows:

application.properties. 

management.endpoints.web.expose=*

Additionally, if Spring Security is present, you would need to add custom security configuration that allows unauthenticated access to the endpoints as shown in the following example:

@Configuration
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {

	@Override
	protected void configure(HttpSecurity http) throws Exception {
		http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests()
			.anyRequest().permitAll()
	}

}

49.4 Configuring Endpoints

Endpoints automatically cache responses to read operations that do not take any parameters. To configure the amount of time for which an endpoint will cache a response, use its cache.time-to-live property. The following example sets the time-to-live of the beans endpoint’s cache to 10 seconds:

application.properties. 

management.endpoint.beans.cache.time-to-live=10s

[Note]Note

The prefix management.endpoint.<name> is used to uniquely identify the endpoint that is being configured.

49.5 Hypermedia for Actuator Web Endpoints

A “discovery page” is added with links to all the endpoints. The “discovery page” is available on /actuator by default.

When a custom management context path is configured, the “discovery page” automatically moves from /actuator to the root of the management context. For example, if the management context path is /management, then the discovery page is available from /management. When the management context path is set to /, the discovery page is disabled to prevent the possibility of a clash with other mappings.

49.6 Actuator Web Endpoint Paths

By default, endpoints are exposed over HTTP under the /actuator path by using the ID of the endpoint. For example, the beans endpoint is exposed under /actuator/beans. If you want to map endpoints to a different path, you can use the management.endpoints.web.path-mapping property. Also, if you want change the base path, you can use management.endpoints.web.base-path.

The following example remaps /actuator/health to /healthcheck:

application.properties. 

management.endpoints.web.base-path=/
management.endpoints.web.path-mapping.health=healthcheck

49.7 CORS Support

Cross-origin resource sharing (CORS) is a W3C specification that lets you specify in a flexible way what kind of cross-domain requests are authorized. If you use Spring MVC or Spring WebFlux, Actuator’s web endpoints can be configured to support such scenarios.

CORS support is disabled by default and is only enabled once the management.endpoints.web.cors.allowed-origins property has been set. The following configuration permits GET and POST calls from the example.com domain:

management.endpoints.web.cors.allowed-origins=http://example.com
management.endpoints.web.cors.allowed-methods=GET,POST
[Tip]Tip

See CorsEndpointProperties for a complete list of options.

49.8 Adding Custom Endpoints

If you add a @Bean annotated with @Endpoint, any methods annotated with @ReadOperation, @WriteOperation, or @DeleteOperation are automatically exposed over JMX and, in a web application, over HTTP as well.

You can also write technology-specific endpoints by using @JmxEndpoint or @WebEndpoint. These endpoints are filtered to their respective technologies. For example, @WebEndpoint is exposed only over HTTP and not over JMX.

Finally, you can write technology-specific extensions by using @EndpointWebExtension and @EndpointJmxExtension. These annotations let you provide technology-specific operations to augment an existing endpoint.

[Tip]Tip

If you add endpoints as a library feature, consider adding a configuration class annotated with @ManagementContextConfiguration to /META-INF/spring.factories under the following key: org.springframework.boot.actuate.autoconfigure.web.ManagementContextConfiguration. If you do so and if your users ask for a separate management port or address, the endpoint moves to a child context with all the other web endpoints.

49.9 Health Information

You can use health information to check the status of your running application. It is often used by monitoring software to alert someone when a production system goes down. The information exposed by the health endpoint depends on the management.endpoint.health.show-details property. By default, the property’s value is false and a simple “status” message is returned. When the property’s value is set to true, additional details from the individual health indicators are also displayed.

Health information is collected from all HealthIndicator beans defined in your ApplicationContext. Spring Boot includes a number of auto-configured HealthIndicators, and you can also write your own. By default, the final system state is derived by the HealthAggregator, which sorts the statuses from each HealthIndicator based on an ordered list of statuses. The first status in the sorted list is used as the overall health status. If no HealthIndicator returns a status that is known to the HealthAggregator, an UNKNOWN status is used.

49.9.1 Auto-configured HealthIndicators

The following HealthIndicators are auto-configured by Spring Boot when appropriate:

NameDescription

CassandraHealthIndicator

Checks that a Cassandra database is up.

DiskSpaceHealthIndicator

Checks for low disk space.

DataSourceHealthIndicator

Checks that a connection to DataSource can be obtained.

ElasticsearchHealthIndicator

Checks that an Elasticsearch cluster is up.

InfluxDbHealthIndicator

Checks that an InfluxDB server is up.

JmsHealthIndicator

Checks that a JMS broker is up.

MailHealthIndicator

Checks that a mail server is up.

MongoHealthIndicator

Checks that a Mongo database is up.

Neo4jHealthIndicator

Checks that a Neo4j server is up.

RabbitHealthIndicator

Checks that a Rabbit server is up.

RedisHealthIndicator

Checks that a Redis server is up.

SolrHealthIndicator

Checks that a Solr server is up.

[Tip]Tip

You can disable them all by setting the management.health.defaults.enabled property.

49.9.2 Writing Custom HealthIndicators

To provide custom health information, you can register Spring beans that implement the HealthIndicator interface. You need to provide an implementation of the health() method and return a Health response. The Health response should include a status and can optionally include additional details to be displayed. The following code shows a sample HealthIndicator implementation:

import org.springframework.boot.actuate.health.Health;
import org.springframework.boot.actuate.health.HealthIndicator;
import org.springframework.stereotype.Component;

@Component
public class MyHealthIndicator implements HealthIndicator {

	@Override
	public Health health() {
		int errorCode = check(); // perform some specific health check
		if (errorCode != 0) {
			return Health.down().withDetail("Error Code", errorCode).build();
		}
		return Health.up().build();
	}

}
[Note]Note

The identifier for a given HealthIndicator is the name of the bean without the HealthIndicator suffix, if it exists. In the preceding example, the health information is available in an entry named my.

In addition to Spring Boot’s predefined Status types, it is also possible for Health to return a custom Status that represents a new system state. In such cases, a custom implementation of the HealthAggregator interface also needs to be provided, or the default implementation has to be configured by using the management.health.status.order configuration property.

For example, assume a new Status with code FATAL is being used in one of your HealthIndicator implementations. To configure the severity order, add the following property to your application properties:

management.health.status.order=FATAL, DOWN, OUT_OF_SERVICE, UNKNOWN, UP

The HTTP status code in the response reflects the overall health status (for example, UP maps to 200, while OUT_OF_SERVICE and DOWN map to 503). You might also want to register custom status mappings if you access the health endpoint over HTTP. For example, the following property maps FATAL to 503 (service unavailable):

management.health.status.http-mapping.FATAL=503
[Tip]Tip

If you need more control, you can define your own HealthStatusHttpMapper bean.

The following table shows the default status mappings for the built-in statuses:

StatusMapping

DOWN

SERVICE_UNAVAILABLE (503)

OUT_OF_SERVICE

SERVICE_UNAVAILABLE (503)

UP

No mapping by default, so http status is 200

UNKNOWN

No mapping by default, so http status is 200

49.9.3 Reactive Health Indicators

For reactive applications, such as those using Spring WebFlux, ReactiveHealthIndicator provides a non-blocking contract for getting application health. Similar to a traditional HealthIndicator, health information is collected from all ReactiveHealthIndicator beans defined in your ApplicationContext. Regular HealthIndicator beans that do not check against a reactive API are included and executed on the elastic scheduler.

To provide custom health information from a reactive API, you can register Spring beans that implement the ReactiveHealthIndicator interface. The following code shows a sample ReactiveHealthIndicator implementation:

@Component
public class MyReactiveHealthIndicator implements ReactiveHealthIndicator {

	@Override
	public Mono<Health> health() {
		return doHealthCheck() //perform some specific health check that returns a Mono<Health>
			.onErrorResume(ex -> Mono.just(new Health.Builder().down(ex).build())));
	}

}
[Tip]Tip

To handle the error automatically, consider extending from AbstractReactiveHealthIndicator.

49.9.4 Auto-configured ReactiveHealthIndicators

The following ReactiveHealthIndicators are auto-configured by Spring Boot when appropriate:

NameDescription

RedisReactiveHealthIndicator

Checks that a Redis server is up.

[Tip]Tip

If necessary, reactive indicators replace the regular ones. Also, any HealthIndicator that is not handled explicitly is wrapped automatically.

49.10 Application Information

Application information exposes various information collected from all InfoContributor beans defined in your ApplicationContext. Spring Boot includes a number of auto-configured InfoContributor beans, and you can write your own.

49.10.1 Auto-configured InfoContributors

The following InfoContributor beans are auto-configured by Spring Boot, when appropriate:

NameDescription

EnvironmentInfoContributor

Exposes any key from the Environment under the info key.

GitInfoContributor

Exposes git information if a git.properties file is available.

BuildInfoContributor

Exposes build information if a META-INF/build-info.properties file is available.

[Tip]Tip

It is possible to disable them all by setting the management.info.defaults.enabled property.

49.10.2 Custom Application Information

You can customize the data exposed by the info endpoint by setting info.* Spring properties. All Environment properties under the info key are automatically exposed. For example, you could add the following settings to your application.properties file:

info.app.encoding=UTF-8
info.app.java.source=1.8
info.app.java.target=1.8
[Tip]Tip

Rather than hardcoding those values, you could also expand info properties at build time.

Assuming you use Maven, you could rewrite the preceding example as follows:

info.app.encoding[email protected]@
info.app.java.source[email protected]@
info.app.java.target[email protected]@

49.10.3 Git Commit Information

Another useful feature of the info endpoint is its ability to publish information about the state of your git source code repository when the project was built. If a GitProperties bean is available, the git.branch, git.commit.id, and git.commit.time properties are exposed.

[Tip]Tip

A GitProperties bean is auto-configured if a git.properties file is available at the root of the classpath. See "Generate git information" for more details.

If you want to display the full git information (that is, the full content of git.properties), use the management.info.git.mode property, as follows:

management.info.git.mode=full

49.10.4 Build Information

If a BuildProperties bean is available, the info endpoint can also publish information about your build. This happens if a META-INF/build-info.properties file is available in the classpath.

[Tip]Tip

The Maven and Gradle plugins can both generate that file. See "Generate build information" for more details.

49.10.5 Writing Custom InfoContributors

To provide custom application information, you can register Spring beans that implement the InfoContributor interface.

The following example contributes an example entry with a single value:

import java.util.Collections;

import org.springframework.boot.actuate.info.Info;
import org.springframework.boot.actuate.info.InfoContributor;
import org.springframework.stereotype.Component;

@Component
public class ExampleInfoContributor implements InfoContributor {

	@Override
	public void contribute(Info.Builder builder) {
		builder.withDetail("example",
				Collections.singletonMap("key", "value"));
	}

}

If you reach the info endpoint, you should see a response that contains the following additional entry:

{
	"example": {
		"key" : "value"
	}
}