Art is good for eyes. Spring boot out of the box comes with a nice text banner of it's name : Spring Boot and displays the version right below the banner. Out of the box, the banner mode is set on and it shows up when the application gets started. There are several articles available on customizing this banner. Also, spring boot documentation has a brief section on thus as well (link in the resources).
Environment: Java 20, Spring Boot 2.7.14, maven 3.9.3 on macOS Catalina 10.15.7
It's always good to customize the banner and see your application name whenever it comes up. Of course, you can display more good-to-have version details like: Spring Boot version, Java version, Your application version, and other available properties along with the banner.
Following is the quick list of steps to have a custom banner in your application.
- Generate a text banner for your application name. There are several sites for doing this. The one such is: https://devops.datenkollektiv.de/banner.txt/index.html. Generate a text banner and download the text file. I usually go with the standard banner font.
- Edit the file and add the following properties for versions at the bottom:
____ _ ____ ___ __
| __ ) ___ ___ | |_ / ___|_ __ __ _ __ _| \ \ / / __ ___
| _ \ / _ \ / _ \| __| | | _| '__/ _` |/ _` | |\ \ / / '_ ` _ \
| |_) | (_) | (_) | |_ | |_| | | | (_| | (_| | | \ V /| | | | | |
|____/ \___/ \___/ \__| \____|_| \__,_|\__,_|_| \_/ |_| |_| |_|
:: Spring Boot :: ${spring-boot.version}
:: Running on Java :: ${java.version}
:: Application :: ${project.version}
- Place the text file with file-name: banner.txt under src/java/resources folder.
- In your maven build file (pom.xml), make sure that you turn on maven filtering and add the resource directory for the extra version properties added to be resolved during the build.
- Also, make sure you have maven-resources-plugin configured to filter resources.
<build>
<resources>
<resource>
<filtering>true</filtering>
<directory>${project.basedir}/src/main/resources/</directory>
</resource>
</resources>
<testResources>
<testResource>
<filtering>true</filtering>
<directory>${project.basedir}/src/test/resources/</directory>
</testResource>
</testResources>
...
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>3.3.1</version>
<executions>
<execution>
<id>filter-resources</id>
<phase>process-resources</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<resources>
<!-- # Filtered Resources -->
<resource>
<directory>${project.basedir}/src/main/resources/</directory>
<filtering>true</filtering>
</resource>
</resources>
<outputDirectory>${project.build.directory}</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
...
</build>
Gotcha-1
When you run maven build goal(s) that also runs test-cases like for e.g. ./mvnw clean install, the banner shows up with all properties resolved for every integration test-case. However, for the custom properties used in the banner to be filtered and shown you need to add the same custom property in application.yml if you happen to separate out test configurations under test/resources. Also, make sure that you have enabled <testResources> filtering as well as shown above.
Gotcha-2 (Spring Boot 3.x)
The above ${project.version} doesn't work in Spring boot 3.x. In this case a custom application version property (e.g. app.version) can be defined in application.yml or application.properties and that can be used in the banner.txt file.
E.g. application.yml
spring:
application:
name: @project.name@
# custom property for banner
app:
version: @project.version@
____ _ ____ ___ __
| __ ) ___ ___ | |_ / ___|_ __ __ _ __ _| \ \ / / __ ___
| _ \ / _ \ / _ \| __| | | _| '__/ _` |/ _` | |\ \ / / '_ ` _ \
| |_) | (_) | (_) | |_ | |_| | | | (_| | (_| | | \ V /| | | | | |
|____/ \___/ \___/ \__| \____|_| \__,_|\__,_|_| \_/ |_| |_| |_|
:: Spring Boot :: ${spring-boot.version}
:: Running on Java :: ${java.version}
:: Application :: ${app.version}
Actuator
Actuator provides production-ready endpoints for monitoring the application. Just adding the following dependency in pom.xml will do. Once the application is up, check http://localhost:8080/actuator
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
However, by default not all end-points are enabled. Only /actuator, and /actuator/health end-points are enabled. By setting the property management.endpoints.web.exposure.include=* in application.properties or corresponding application.yml will activate all end-points.
Also, multiple end-points can be listed separated by comma.
e.g. management.endpoints.web.exposure.include=health,info,beans,env
Selectively certain end-points can be disabled, for instance to disable refresh end-point, set management.endpoints.web.exposure.exclude=refresh
NOTE: The refresh end-point requires an empty POST request. e.g. curl -X POST http://localhost:8081/actuator/refresh
Maven plugin - spring-boot-maven-plugin
Which would result with additional properties in the build-info.properties file like:
The /actuator/info endpoint response looks like:
Application information
The /actuator/info endpoint displays application information. By default there is no information. So, http://localhost:8080/actuator/info displays empty JSON:
{}
This plugin comes with build execution goal: build-info which is run by default and creates build information file: build-info.properties under target/classes/META_INF directory. Properties listed in this file are available through the endpoint: http://localhost:8080/actuator/info.
The following is an example of build-info goal execution configuration:
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<!-- Useful info on /actuator/info -->
<id>build-info</id>
<goals>
<goal>build-info</goal>
</goals>
</execution>
</executions>
</plugin>
The above configuration generates build-info.properties file with pre-defined build info properties like:
build.artifact=boot-graalvm
build.group=com.example
build.name=boot-graalvm
build.time=2023-09-22T16\:04\:27.970Z
build.version=0.0.1-SNAPSHOT
With the above file generated, the /actuator/info endpoint response would look like:
{
"build": {
"artifact": "boot-graalvm",
"name": "boot-graalvm",
"time": "2023-09-22T16:04:27.970Z",
"version": "0.0.1-SNAPSHOT",
"group": "com.example"
}
}
Additional custom properties can be added by configuring the build-info goal. For instance to add Java version and the Spring Boot version that the application is running with, the following additional configuration can be added:
...
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>3.1.2</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>boot-graalvm</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>boot-graalvm</name>
<description>GraalVm project for Spring Boot</description>
<properties>
<java.version>20</java.version>
<spring.boot.version>${parent.version}</spring.boot.version>
</properties>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<!-- Useful info on /actuator/info -->
<id>build-info</id>
<goals>
<goal>build-info</goal>
</goals>
<configuration>
<additionalProperties>
<java.version>${java.version}</java.version>
<spring.boot.version>${spring.boot.version}</spring.boot.version>
</additionalProperties>
</configuration>
</execution>
</executions>
...
Which would result with additional properties in the build-info.properties file like:
build.java.version=20
build.spring.boot.version=3.1.2
The /actuator/info endpoint response looks like:
{
"build": {
"java": {
"version": "20"
},
"spring": {
"boot": {
"version": "3.1.2"
}
},
"version": "0.0.1-SNAPSHOT",
"artifact": "boot-graalvm",
"name": "boot-graalvm",
"time": "2023-09-22T18:52:39.193Z",
"group": "com.example"
}
}
Java information
Info endpoint has several info contributors like build, env, java, git etc. By default they are disabled. Enabling these would show related information collected by Spring.
To enable java info, add management.info.java.enabled=true in application.properties or management.info.java.enabled:true in application.yml.
This will show the following java info details collected like:
{
"build": {
"java": {
"version": "20"
},
"spring": {
"boot": {
"version": "3.1.2"
}
},
"version": "0.0.1-SNAPSHOT",
"artifact": "boot-graalvm",
"name": "boot-graalvm",
"time": "2023-09-22T18:52:39.193Z",
"group": "com.example"
},
"java": {
"version": "20",
"vendor": {
"name": "Amazon.com Inc.",
"version": "Corretto-20.0.0.36.1"
},
"runtime": {
"name": "OpenJDK Runtime Environment",
"version": "20+36-FR"
},
"jvm": {
"name": "OpenJDK 64-Bit Server VM",
"vendor": "Amazon.com Inc.",
"version": "20+36-FR"
}
}
}
TIP
These build properties generated and available through /actuator/info are also are available through BuildProperties object which can be auto-wired into any of the Spring managed beans and be accessed. For instance these properties can be outputted on swagger-ui page.
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