Spring Boot Actuator and Dev Tools

In the previous article, we learned about Setting up spring security and Swagger-UI in Spring boot. (Setting Up Spring Security and Swagger-UI)

What you will learn from this blog?

1. Using Spring Boot Actuator

2. Using Spring Boot Dev Tools

Spring Boot Actuator

Spring Boot Actuator is a sub-project of Spring Boot which adds several production-ready services to our applications.

To look further, Let us create a Spring Boot Application using Spring initializr.

We have added the Spring Web, Spring Boot Actuator and Spring Boot DevTools dependencies.

Spring Boot Actuator, Provides several endpoints out of which only /health is enabled by default. We can see all the enabled URLs using the actuator URL below.

The /health endpoint provides us with the application running status.

We can enable the other end-points provided by the actuator using the below property in the application.properties file.

use the property management.endpoints.web.exposure.include=* and invoke the actuator endpoint to view the endpoints that are provided.

We can also enable only a few endpoints by using the include property and similarly exclude a few endpoints using the exclude property.

management.endpoints.web.exposure.include=health,info management.endpoints.web.exposure.exclude=env,beans

endpoints	Description
/auditevents	Exposes audit events information for the current application. Requires an AuditEventRepository bean.
/beans	Displays a complete list of all the Spring beans in your application.
/conditions	Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match.
/configprops	Displays a collated list of all @ConfigurationProperties.
/env	Exposes properties from Spring’s ConfigurableEnvironment.
/health	Shows application health information.
/info	Displays arbitrary application info.
/loggers	Shows and modifies the configuration of loggers in the application.
/metrics	Shows “metrics” information for the current application.
/shutdown	Lets the application be gracefully shut down. Disabled by default.

The table above provides some of the most used endpoints of actuators.

By using the below properties, We can define a separate port for actuator endpoints and application endpoints.

The Actuator endpoints will be exposed on 9001 and the application endpoints on 9000.

Spring Boot DevTools

We can enable the DevTools by adding the below dependency in pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    <optional>true</optional>
</dependency>

Spring Boot Dev Tools provide us with various features out of which we will be learning the most used features.

DevTools are built only for development-specific purposes and it gets auto-disabled in the production environment/setting.

Property Defaults

Spring Boot does a lot of auto-configurations including caching to improve performance, One such example is caching of templates while using thymeleaf.

But during the development, We need to refresh the cache each time when there is a change which can be easily done by using Dev Tools.

Auto Restart

In Development Environment, We do frequent changes to the code and would need to restart the embedded server each time to validate the changes.

DevTools provides the capability of Auto restart and whenever there is a change in the code the server gets restarted.

To test this feature, start the server and change the code. Try to compile the project in another terminal using mvn compile, the server will restart as shown below.

If the build project automatically option is enabled in the IDE, then the code changes will result in the compilation of classes and the server gets restarted automatically.

Live Reload

Spring Boot Dev Tools provides a Live reload server which is used to trigger the browser refresh whenever there is a change in the resource.

For this to happen we need to install the Live reload plugin in the browser. This feature is mostly used for UI changes.

Global Settings

Spring Boot Dev Tools provides us with the option to group our favourite configuration in a file that can be reused for various projects.

We can define the global config file in the system users home directory with the following name .spring-boot-devtools.properties

Finally, We have understood the benefits of Spring Boot Actuator and Dev Tools. We are also able to integrate and test some of its features.

The source code is available on GitHub mentioned below

You can follow me on Twitter and Linkedin to stay updated with my blogs. Happy Learning .. 😊👍