Andy Wilkinson 0de466e06e Require dependency on s-b-dependencies to use its constraints
Previously, Spring Boot's modules published Gradle Module Metadata
(GMM) the declared a platform dependency on spring-boot-dependencies.
This provided versions for each module's own dependencies but also had
they unwanted side-effect of pulling in spring-boot-dependencies
constraints which would influence the version of other dependencies
declared in the same configuration. This was undesirable as users
should be able to opt in to this level of dependency management, either
by using the dependency management plugin or by using Gradle's built-in
support via a platform dependency on spring-boot-dependencies.

This commit reworks how Spring Boot's build uses
spring-boot-dependencies and spring-boot-parent to provide its own
dependency management. Configurations that aren't seen by consumers are
configured to extend a dependencyManagement configuration that has an
enforced platform dependency on spring-boot-parent. This enforces
spring-boot-parent's version constraints on Spring Boot's build without
making them visible to consumers. To ensure that the versions that
Spring Boot has been built against are visible to consumers, the
Maven publication that produces pom files and GMM for the published
modules is configured to use the resolved versions from the module's
runtime classpath.

Fixes gh-21911
2020-06-16 08:50:21 +01:00
..
2020-06-15 08:41:44 +02:00

= 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
https://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 {
		implementation '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.