1. 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:
ID | Description |
---|---|
|
Exposes audit events information for the current application.
Requires an |
|
Displays a complete list of all the Spring beans in your application. |
|
Exposes available caches. |
|
Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match. |
|
Displays a collated list of all |
|
Exposes properties from Spring’s |
|
Shows any Flyway database migrations that have been applied.
Requires one or more |
|
Shows application health information. |
|
Displays HTTP trace information (by default, the last 100 HTTP request-response exchanges).
Requires an |
|
Displays arbitrary application info. |
|
Shows the Spring Integration graph.
Requires a dependency on |
|
Shows and modifies the configuration of loggers in the application. |
|
Shows any Liquibase database migrations that have been applied.
Requires one or more |
|
Shows ‘metrics’ information for the current application. |
|
Displays a collated list of all |
|
Displays the scheduled tasks in your application. |
|
Allows retrieval and deletion of user sessions from a Spring Session-backed session store. Requires a Servlet-based web application using Spring Session. |
|
Lets the application be gracefully shutdown. Disabled by default. |
|
Performs a thread dump. |
If your application is a web application (Spring MVC, Spring WebFlux, or Jersey), you can use the following additional endpoints:
ID | Description |
---|---|
|
Returns an |
|
Exposes JMX beans over HTTP (when Jolokia is on the classpath, not available for WebFlux).
Requires a dependency on |
|
Returns the contents of the logfile (if |
|
Exposes metrics in a format that can be scraped by a Prometheus server.
Requires a dependency on |
To learn more about the Actuator’s endpoints and their request and response formats, please refer to the separate API documentation (HTML or PDF).
1.1. Enabling Endpoints
By default, all endpoints except for shutdown
are enabled.
To configure the enablement of an endpoint, use its management.endpoint.<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 configprop: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
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 include and exclude properties instead.
|
1.2. 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:
ID | JMX | Web |
---|---|---|
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
Yes |
|
N/A |
No |
|
Yes |
No |
|
Yes |
Yes |
|
Yes |
No |
|
N/A |
No |
|
N/A |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
N/A |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
|
Yes |
No |
To change which endpoints are exposed, use the following technology-specific include
and exclude
properties:
Property | Default |
---|---|
configprop:management.endpoints.jmx.exposure.exclude[] |
|
configprop:management.endpoints.jmx.exposure.include[] |
|
configprop:management.endpoints.web.exposure.exclude[] |
|
configprop:management.endpoints.web.exposure.include[] |
|
The include
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 include
property.
Both include
and exclude
properties can be configured with a list of endpoint IDs.
For example, to stop exposing all endpoints over JMX and only expose the health
and info
endpoints, use the following property:
management.endpoints.jmx.exposure.include=health,info
*
can be used to select all endpoints.
For example, to expose everything over HTTP except the env
and beans
endpoints, use the following properties:
management.endpoints.web.exposure.include=*
management.endpoints.web.exposure.exclude=env,beans
|
If your application is exposed publicly, we strongly recommend that you also secure your endpoints. |
If you want to implement your own strategy for when endpoints are exposed, you can register an EndpointFilter bean.
|
1.3. 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(proxyBeanMethods = false)
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) ->
requests.anyRequest().hasRole("ENDPOINT_ADMIN"));
http.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 configprop:management.endpoints.web.exposure.include[] property, as follows:
management.endpoints.web.exposure.include=*
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(proxyBeanMethods = false)
public class ActuatorSecurity extends WebSecurityConfigurerAdapter {
@Override
protected void configure(HttpSecurity http) throws Exception {
http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) ->
requests.anyRequest().permitAll());
}
}
1.4. 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:
management.endpoint.beans.cache.time-to-live=10s
The prefix management.endpoint.<name> is used to uniquely identify the endpoint that is being configured.
|
When making an authenticated HTTP request, the Principal is considered as input to the endpoint and, therefore, the response will not be cached.
|
1.5. 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.
1.6. 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 configprop: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=https://example.com
management.endpoints.web.cors.allowed-methods=GET,POST
See CorsEndpointProperties for a complete list of options. |
1.7. Implementing 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.
Endpoints can be exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux.
If both Jersey and Spring MVC are available, Spring MVC will be used.
You can also write technology-specific endpoints by using @JmxEndpoint
or @WebEndpoint
.
These endpoints are restricted to their respective technologies.
For example, @WebEndpoint
is exposed only over HTTP and not over JMX.
You can write technology-specific extensions by using @EndpointWebExtension
and @EndpointJmxExtension
.
These annotations let you provide technology-specific operations to augment an existing endpoint.
Finally, if you need access to web-framework-specific functionality, you can implement Servlet or Spring @Controller
and @RestController
endpoints at the cost of them not being available over JMX or when using a different web framework.
1.7.1. Receiving Input
Operations on an endpoint receive input via their parameters.
When exposed via the web, the values for these parameters are taken from the URL’s query parameters and from the JSON request body.
When exposed via JMX, the parameters are mapped to the parameters of the MBean’s operations.
Parameters are required by default.
They can be made optional by annotating them with @org.springframework.lang.Nullable
.
Each root property in the JSON request body can be mapped to a parameter of the endpoint. Consider the following JSON request body:
{
"name": "test",
"counter": 42
}
This can be used to invoke a write operation that takes String name
and int counter
parameters.
Because endpoints are technology agnostic, only simple types can be specified in the method signature.
In particular declaring a single parameter with a custom type defining a name and counter properties is not supported.
|
To allow the input to be mapped to the operation method’s parameters, Java code implementing an endpoint should be compiled with -parameters , and Kotlin code implementing an endpoint should be compiled with -java-parameters .
This will happen automatically if you are using Spring Boot’s Gradle plugin or if you are using Maven and spring-boot-starter-parent .
|
Input type conversion
The parameters passed to endpoint operation methods are, if necessary, automatically converted to the required type.
Before calling an operation method, the input received via JMX or an HTTP request is converted to the required types using an instance of ApplicationConversionService
as well as any Converter
or GenericConverter
beans qualified with @EndpointConverter
.
1.7.2. Custom Web Endpoints
Operations on an @Endpoint
, @WebEndpoint
, or @EndpointWebExtension
are automatically exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux.
If both Jersey and Spring MVC are available, Spring MVC will be used.
Web Endpoint Request Predicates
A request predicate is automatically generated for each operation on a web-exposed endpoint.
Path
The path of the predicate is determined by the ID of the endpoint and the base path of web-exposed endpoints.
The default base path is /actuator
.
For example, an endpoint with the ID sessions
will use /actuator/sessions
as its path in the predicate.
The path can be further customized by annotating one or more parameters of the operation method with @Selector
.
Such a parameter is added to the path predicate as a path variable.
The variable’s value is passed into the operation method when the endpoint operation is invoked.
If you want to capture all remaining path elements, you can add @Selector(Match=ALL_REMAINING)
to the last parameter and make it a type that is conversion compatible with a String[]
.
HTTP method
The HTTP method of the predicate is determined by the operation type, as shown in the following table:
Operation | HTTP method |
---|---|
|
|
|
|
|
|
Consumes
For a @WriteOperation
(HTTP POST
) that uses the request body, the consumes clause of the predicate is application/vnd.spring-boot.actuator.v2+json, application/json
.
For all other operations the consumes clause is empty.
Produces
The produces clause of the predicate can be determined by the produces
attribute of the @DeleteOperation
, @ReadOperation
, and @WriteOperation
annotations.
The attribute is optional.
If it is not used, the produces clause is determined automatically.
If the operation method returns void
or Void
the produces clause is empty.
If the operation method returns a org.springframework.core.io.Resource
, the produces clause is application/octet-stream
.
For all other operations the produces clause is application/vnd.spring-boot.actuator.v2+json, application/json
.
Web Endpoint Response Status
The default response status for an endpoint operation depends on the operation type (read, write, or delete) and what, if anything, the operation returns.
A @ReadOperation
returns a value, the response status will be 200 (OK).
If it does not return a value, the response status will be 404 (Not Found).
If a @WriteOperation
or @DeleteOperation
returns a value, the response status will be 200 (OK).
If it does not return a value the response status will be 204 (No Content).
If an operation is invoked without a required parameter, or with a parameter that cannot be converted to the required type, the operation method will not be called and the response status will be 400 (Bad Request).
Web Endpoint Range Requests
An HTTP range request can be used to request part of an HTTP resource.
When using Spring MVC or Spring Web Flux, operations that return a org.springframework.core.io.Resource
automatically support range requests.
Range requests are not supported when using Jersey. |
Web Endpoint Security
An operation on a web endpoint or a web-specific endpoint extension can receive the current java.security.Principal
or org.springframework.boot.actuate.endpoint.SecurityContext
as a method parameter.
The former is typically used in conjunction with @Nullable
to provide different behavior for authenticated and unauthenticated users.
The latter is typically used to perform authorization checks using its isUserInRole(String)
method.
1.7.3. Servlet endpoints
A Servlet
can be exposed as an endpoint by implementing a class annotated with @ServletEndpoint
that also implements Supplier<EndpointServlet>
.
Servlet endpoints provide deeper integration with the Servlet container but at the expense of portability.
They are intended to be used to expose an existing Servlet
as an endpoint.
For new endpoints, the @Endpoint
and @WebEndpoint
annotations should be preferred whenever possible.
1.7.4. Controller endpoints
@ControllerEndpoint
and @RestControllerEndpoint
can be used to implement an endpoint that is only exposed by Spring MVC or Spring WebFlux.
Methods are mapped using the standard annotations for Spring MVC and Spring WebFlux such as @RequestMapping
and @GetMapping
, with the endpoint’s ID being used as a prefix for the path.
Controller endpoints provide deeper integration with Spring’s web frameworks but at the expense of portability.
The @Endpoint
and @WebEndpoint
annotations should be preferred whenever possible.
1.8. 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 configprop:management.endpoint.health.show-details[] and configprop:management.endpoint.health.show-components[] properties which can be configured with one of the following values:
Name | Description |
---|---|
|
Details are never shown. |
|
Details are only shown to authorized users.
Authorized roles can be configured using |
|
Details are shown to all users. |
The default value is never
.
A user is considered to be authorized when they are in one or more of the endpoint’s roles.
If the endpoint has no configured roles (the default) all authenticated users are considered to be authorized.
The roles can be configured using the configprop:management.endpoint.health.roles[] property.
If you have secured your application and wish to use always , your security configuration must permit access to the health endpoint for both authenticated and unauthenticated users.
|
Health information is collected from the content of a HealthContributorRegistry
(by default all HealthContributor
instances defined in your ApplicationContext
).
Spring Boot includes a number of auto-configured HealthContributors
and you can also write your own.
A HealthContributor
can either be a HealthIndicator
or a CompositeHealthContributor
.
A HealthIndicator
provides actual health information, including a Status
.
A CompositeHealthContributor
provides a composite of other HealthContributors
.
Taken together, contributors form a tree structure to represent the overall system health.
By default, the final system health is derived by a StatusAggregator
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 StatusAggregator
, an UNKNOWN
status is used.
The HealthContributorRegistry can be used to register and unregister health indicators at runtime.
|
1.8.1. Auto-configured HealthIndicators
The following HealthIndicators
are auto-configured by Spring Boot when appropriate:
Name | Description |
---|---|
Checks that a Cassandra database is up. |
|
Checks that a Couchbase cluster is up. |
|
Checks for low disk space. |
|
Checks that an Elasticsearch cluster is up. |
|
Checks that a Hazelcast server is up. |
|
Checks that an InfluxDB server is up. |
|
Checks that a JMS broker is up. |
|
Checks that an LDAP server is up. |
|
Checks that a mail server is up. |
|
Checks that a Mongo database is up. |
|
Checks that a Neo4j database is up. |
|
Always responds with |
|
Checks that a Rabbit server is up. |
|
Checks that a Redis server is up. |
|
Checks that a Solr server is up. |
You can disable them all by setting the configprop:management.health.defaults.enabled[] property. |
1.8.2. 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();
}
}
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 StatusAggregator
interface also needs to be provided, or the default implementation has to be configured by using the configprop:management.endpoint.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.endpoint.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.endpoint.health.status.http-mapping.fatal=503
If you need more control, you can define your own HttpCodeStatusMapper bean.
|
The following table shows the default status mappings for the built-in statuses:
Status | Mapping |
---|---|
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 |
1.8.3. Reactive Health Indicators
For reactive applications, such as those using Spring WebFlux, ReactiveHealthContributor
provides a non-blocking contract for getting application health.
Similar to a traditional HealthContributor
, health information is collected from the content of a ReactiveHealthContributorRegistry
(by default all HealthContributor
and ReactiveHealthContributor
instances defined in your ApplicationContext
).
Regular HealthContributors
that do not check against a reactive API are executed on the elastic scheduler.
In a reactive application, The ReactiveHealthContributorRegistry can be used to register and unregister health indicators at runtime.
|
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()));
}
}
To handle the error automatically, consider extending from AbstractReactiveHealthIndicator .
|
1.8.4. Auto-configured ReactiveHealthIndicators
The following ReactiveHealthIndicators
are auto-configured by Spring Boot when appropriate:
Name | Description |
---|---|
Checks that a Cassandra database is up. |
|
Checks that a Couchbase cluster is up. |
|
Checks that a Mongo database is up. |
|
Checks that a Redis server is up. |
If necessary, reactive indicators replace the regular ones.
Also, any HealthIndicator that is not handled explicitly is wrapped automatically.
|
1.8.5. Health Groups
It’s sometimes useful to organize health indicators into groups that can be used for different purposes. For example, if you deploy your application to Kubernetes, you may want one different sets of health indicators for your “liveness” and “readiness” probes.
To create a health indicator group you can use the management.endpoint.health.group.<name>
property and specify a list of health indicator IDs to include
or exclude
.
For example, to create a group that includes only database indicators you can define the following:
management.endpoint.health.group.custom.include=db
You can then check the result by hitting localhost:8080/actuator/health/custom
.
By default groups will inherit the same StatusAggregator
and HttpCodeStatusMapper
settings as the system health, however, these can also be defined on a per-group basis.
It’s also possible to override the show-details
and roles
properties if required:
management.endpoint.health.group.custom.show-details=when-authorized
management.endpoint.health.group.custom.roles=admin
management.endpoint.health.group.custom.status.order=fatal,up
management.endpoint.health.group.custom.status.http-mapping.fatal=500
You can use @Qualifier("groupname") if you need to register custom StatusAggregator or HttpCodeStatusMapper beans for use with the group.
|
1.9. 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.
1.9.1. Auto-configured InfoContributors
The following InfoContributor
beans are auto-configured by Spring Boot, when appropriate:
Name | Description |
---|---|
Exposes any key from the |
|
Exposes git information if a |
|
Exposes build information if a |
It is possible to disable them all by setting the configprop:management.info.defaults.enabled[] property. |
1.9.2. 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
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: |
1.9.3. 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.
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 configprop:management.info.git.mode[] property, as follows:
management.info.git.mode=full
1.9.4. 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.
The Maven and Gradle plugins can both generate that file. See "Generate build information" for more details. |
1.9.5. 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"
}
}