Paketo Buildpack for Spring Boot

Buildpack ID: paketo-buildpacks/spring-boot

Registry URLs: docker.io/paketobuildpacks/spring-boot

The Paketo Buildpack for Spring Boot is a Cloud Native Buildpack that contributes Spring Boot dependency information and slices an application into multiple layers.

Behavior

This buildpack will always detect.

This buildpack will participate at build time if all the following conditions are met:

• <APPLICATION_ROOT>/META-INF/MANIFEST.MF contains a Spring-Boot-Version entry

The buildpack will do the following:

• Contributes Spring Boot version to org.springframework.boot.version image label
• If <APPLICATION_ROOT>/META-INF/dataflow-configuration-metadata.properties exists
  • Contributes Spring Boot configuration metadata to org.springframework.boot.spring-configuration-metadata.json image label
  • Contributes Spring Cloud Data Flow configuration metadata to org.springframework.cloud.dataflow.spring-configuration-metadata.json image label
• Contributes Implementation-Title manifest entry to org.opencontainers.image.title image label
• Contributes Implementation-version manifest entry to org.opencontainers.image.version image label
• Contributes dependency information extracted from Maven naming conventions to the image's BOM
• When contributing to a JVM application:
  • Contributes Spring Cloud Bindings as an application dependency
    • This enables bindings-aware Spring Boot auto-configuration when CNB bindings are present during launch
    • The version of the Spring Cloud Bindings library to install will be determined by (in order):
      • An explicit value set in BP_SPRING_CLOUD_BINDINGS_VERSION by the user
      • The Spring Boot version from <APPLICATION_ROOT>/META-INF/MANIFEST.MF: Boot 2.x will install Spring Cloud Bindings v1, Boot 3.x will install Spring Cloud Bindings v2
  • If <APPLICATION_ROOT>/META-INF/MANIFEST.MF contains a Spring-Boot-Layers-Index entry
    • Contributes application slices as defined by the layer's index
  • If the application is a reactive web application
    • Configures $BPL_JVM_THREAD_COUNT to 50
  • If the application is AOT instrumented (presence of META-INF/native-image folder) AND BP_SPRING_AOT_ENABLED is set to true
    • set BPL_SPRING_AOT_ENABLED to true
    • add -Dspring.aot.enabled=true to JAVA_TOOL_OPTIONS at runtime
  • If the application is AOT instrumented (presence of META-INF/native-image folder) AND BP_SPRING_AOT_ENABLED is set to true AND CDS_TRAINING_JAVA_TOOL_OPTIONS is set
    • fail the build with "build failed because of invalid user configuration" - the reason being is that the AOT classes used during training run won't be compatible with a different set of JAVA_TOOL_OPTIONS at runtime
    • the Spring team explains this issue in detail here: spring-projects/spring-boot#41348
• If <APPLICATION_ROOT>/META-INF/MANIFEST.MF contains a Spring-Boot-Native-Processed entry OR if $BP_MAVEN_ACTIVE_PROFILES contains the native profile:
  • A build plan entry is provided, native-image-application, which can be required by the native-image buildpack to automatically trigger a native image build
• When contributing to a native image application:
  • Adds classes from the executable JAR and entries from classpath.idx to the build-time class path, so they are available to native-image

Configuration

Environment Variable	Description
$BP_SPRING_CLOUD_BINDINGS_DISABLED	Whether to contribute Spring Cloud Bindings support to the image at build time. Defaults to false.
$BPL_SPRING_CLOUD_BINDINGS_DISABLED	Whether to auto-configure Spring Boot environment properties from bindings at runtime. This requires Spring Cloud Bindings to have been installed at build time or it will do nothing. Defaults to false.
$BPL_SPRING_CLOUD_BINDINGS_ENABLED	Deprecated in favour of $BPL_SPRING_CLOUD_BINDINGS_DISABLED. Whether to auto-configure Spring Boot environment properties from bindings at runtime. This requires Spring Cloud Bindings to have been installed at build time or it will do nothing. Defaults to true.
$BP_SPRING_CLOUD_BINDINGS_VERSION	Explicit version of Spring Cloud Bindings library to install.
$BP_SPRING_AOT_ENABLED	Whether to contribute $BPL_SPRING_AOT_ENABLED at runtime. Beware that the Spring Boot app needs to have been AOT instrumented (presence of META-INF/native-image) too. Defaults to false.
$BPL_SPRING_AOT_ENABLED	Whether to contribute -Dspring.aot.enabled=true to JAVA_TOOL_OPTIONS at runtime. Defaults to yes if the above conditions were met; false otherwise
$BP_JVM_CDS_ENABLED	Whether to perform the CDS training run (that will generate the caching file application.jsa). Defaults to false.
$CDS_TRAINING_JAVA_TOOL_OPTIONS	Allow the user to override the default JAVA_TOOL_OPTIONS, only for the CDS training run. Useful to configure your app not to reach external services during training run for example.
$BPL_JVM_CDS_ENABLED	Whether to load the CDS caching file (-XX:SharedArchiveFile=application.jsa) that was generated during the CDS training run. Defaults to the value of BP_JVM_CDS_ENABLED

Bindings

The buildpack optionally accepts the following bindings:

Type: dependency-mapping

Key	Value	Description
<dependency-digest>	<uri>	If needed, the buildpack will fetch the dependency with digest <dependency-digest> from <uri>

License

This buildpack is released under version 2.0 of the Apache License.