Actuator endpoints allow you to monitor and interact with your application. Spring Boot
includes a number of built-in endpoints and you can also add your own. For example the
health
endpoint provides basic application health information.
The way that endpoints are exposed will depend on the type of technology that you choose.
Most applications choose HTTP monitoring, where the ID of the endpoint is mapped
to a URL. For example, by default, the health
endpoint will be mapped to /health
.
The following endpoints are available:
ID | Description | Sensitive |
---|---|---|
| Displays an auto-configuration report showing all auto-configuration candidates and the reason why they ‘were’ or ‘were not’ applied. | true |
| Displays a complete list of all the Spring Beans in your application. | true |
| Displays a collated list of all | true |
| Performs a thread dump. | true |
| Exposes properties from Spring’s | true |
| Shows application health information (a simple ‘status’ when accessed over an unauthenticated connection or full message details when authenticated). | false |
| Displays arbitrary application info. | false |
| Shows ‘metrics’ information for the current application. | true |
| Displays a collated list of all | true |
| Allows the application to be gracefully shutdown (not enabled by default). | true |
| Displays trace information (by default the last few HTTP requests). | true |
Note | |
---|---|
Depending on how an endpoint is exposed, the |
Endpoints can be customized using Spring properties. You can change if an endpoint is
enabled
, if it is considered sensitive
and even its id
.
For example, here is an application.properties
that changes the sensitivity and id
of the beans
endpoint and also enables shutdown
.
endpoints.beans.id=springbeans endpoints.beans.sensitive=false endpoints.shutdown.enabled=true
Note | |
---|---|
The prefix ‟ |
By default, all endpoints except for shutdown
are enabled. If you prefer to
specifically “opt-in” endpoint enablement you can use the endpoints.enabled
property.
For example, the following will disable all endpoints except for info
:
endpoints.enabled=false endpoints.info.enabled=true
Health information can be used to check the status of your running application. It is
often used by monitoring software to alert someone if a production system goes down.
The default information exposed by the health
endpoint depends on how it is accessed.
For an insecure unauthenticated connection a simple ‘status’ message is returned, for a
secure or authenticated connection additional details are also displayed (see
Section 41.6, “HTTP Health endpoint access restrictions” for HTTP details).
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.
Information returned by HealthIndicators
is often somewhat sensitive in nature. For
example, you probably don’t want to publish details of your database server to the
world. For this reason, by default, only the health status is exposed over an
unauthenticated HTTP connection. If you are happy for complete health information to always
be exposed you can set endpoints.health.sensitive
to false
.
Health responses are also cached to prevent “denial of service” attacks. Use the
endpoints.health.time-to-live
property if you want to change the default cache period
of 1000 milliseconds.
The following HealthIndicators
are auto-configured by Spring Boot when appropriate:
Name | Description |
---|---|
Checks for low disk space. | |
Checks that a connection to | |
Checks that a Mongo database is up. | |
Checks that a Rabbit server is up. | |
Checks that a Redis server is up. | |
Checks that a Solr server is up. |
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.
import org.springframework.boot.actuate.health.HealthIndicator; import org.springframework.stereotype.Component; @Component public class MyHealth 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(); } }
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
using the management.health.status.order
configuration property.
For example, assuming a new Status
with code FATAL
is being used in one of your
HealthIndicator
implementations. To configure the severity order add the following
to your application properties:
management.health.status.order: DOWN, OUT_OF_SERVICE, UNKNOWN, UP
You might also want to register custom status mappings with the HealthMvcEndpoint
if you access the health endpoint over HTTP. For example you could map FATAL
to
HttpStatus.SERVICE_UNAVAILABLE
.
You can customize the data exposed by the info
endpoint by setting info.*
Spring
properties. All Environment
properties under the info key will be automatically
exposed. For example, you could add the following to your application.properties
:
info.app.name=MyService info.app.description=My awesome service info.app.version=1.0.0
Rather than hardcoding some properties that are also specified in your project’s build configuration, you can automatically expand info properties using the existing build configuration instead. This is possible in both Maven and Gradle.
You can automatically expand info properties from the Maven project using resource
filtering. If you use the spring-boot-starter-parent
you can then refer to your
Maven ‘project properties’ via @..@
placeholders, e.g.
project.artifactId=myproject project.name=Demo project.version=X.X.X.X project.description=Demo project for info endpoint info.build.artifact[email protected]@ info.build.name[email protected]@ info.build.description[email protected]@ info.build.version[email protected]@
Note | |
---|---|
In the above example we used |
Tip | |
---|---|
The |
If you don’t use the starter parent, in your pom.xml
you need (inside the <build/>
element):
<resources> <resource> <directory>src/main/resources</directory> <filtering>true</filtering> </resource> </resources>
and (inside <plugins/>
):
<plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <version>2.6</version> <configuration> <delimiters> <delimiter>@</delimiter> </delimiters> </configuration> </plugin>
You can automatically expand info properties from the Gradle project by configuring
the Java plugin’s processResources
task to do so:
processResources { expand(project.properties) }
You can then refer to your Gradle project’s properties via placeholders, e.g.
info.build.name=${name} info.build.description=${description} info.build.version=${version}
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
git.properties
file is contained in your jar the git.branch
and git.commit
properties will be loaded.
For Maven users the spring-boot-starter-parent
POM includes a pre-configured plugin to
generate a git.properties
file. Simply add the following declaration to your POM:
<build> <plugins> <plugin> <groupId>pl.project13.maven</groupId> <artifactId>git-commit-id-plugin</artifactId> </plugin> </plugins> </build>
A similar gradle-git
plugin is also available
for Gradle users, although a little more work is required to generate the properties file.