Phillip Webb 1d39feffea Overhaul actuator endpoint code
Refactor several areas of the actuator endpoint code in order to make
future extensions easier. The primary goal is to introduce the concept
of an `ExposableEndpoint` that has technology specific subclasses and
can carry additional data for filters to use. Many other changes have
been made along the way including:

* A new EndpointSupplier interface that allows cleaner separation of
  supplying vs discovering endpoints. This allows cleaner class names
  and allows for better auto-configuration since a user can choose to
  provide their own supplier entirely.

* A `DiscoveredEndpoint` interface that allows the `EndpointFilter`
  to be greatly simplified. A filter now doesn't need to know about
  discovery concerns unless absolutely necessary.

* Improved naming and package structure. Many technology specific
  concerns are now grouped in a better way. Related concerns are
  co-located and concepts from one area no longer leakage into another.

* Simplified `HandlerMapping` implementations. Many common concerns have
  been pulled up helping to create simpler subclasses.

* Simplified JMX adapters. Many of the intermediary `Info` classes have
  been removed. The `DiscoveredJmxOperation` is now responsible for
  mapping methods to operations.

* A specific @`HealthEndpointCloudFoundryExtension` for Cloud Foundry.
  The extension logic used to create a "full" health endpoint extension
  has been made explicit.

Fixes gh-11428
Fixes gh-11581
2018-01-19 20:44:24 -08:00
..
2018-01-19 20:44:24 -08:00
2018-01-16 18:26:59 +00:00

= Spring Boot - Actuator

Spring Boot Actuator includes a number of additional features to help you monitor and
manage your application when it's pushed to production. You can choose to manage and
monitor your application using HTTP or JMX endpoints. Auditing, health and metrics
gathering can be automatically applied to your application. The
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready[user guide]
covers the features in more detail.

== Enabling the Actuator
The simplest way to enable the features is to add a dependency to the
`spring-boot-starter-actuator` '`Starter`'. To add the actuator to a Maven-based project,
add the following '`Starter`' dependency:

[source,xml,indent=0]
----
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-actuator</artifactId>
		</dependency>
	</dependencies>
----

For Gradle, use the following declaration:

[indent=0]
----
	dependencies {
		compile("org.springframework.boot:spring-boot-starter-actuator")
	}
----

== Features
* **Endpoints** 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. Run up a basic application and look at `/actuator/health`.
* **Metrics** Spring Boot Actuator provides dimensional metrics by integrating with
  https://micrometer.io[Micrometer].
* **Audit** Spring Boot Actuator has a flexible audit framework that will publish events
  to an `AuditEventRepository`. Once Spring Security is in play it automatically publishes
  authentication events by default. This can be very useful for reporting, and also to
  implement a lock-out policy based on authentication failures.