Document the need to use the launcher to be able to use application.* properties in a custom banner

[orenw1]

Some of the banner properties not populated when running with unpacked jar and custom banner

When running Spring Boot application with custom banner and unpacked jar as documented in [1],
the following banner properties that described in [2] are not printed

• application.version
• application.formatted-version
• application.title

[1] Deploying to Containers

[2] Customizing the Banner

Spring Boot version: 2.3.1.RELEASE

i saw this #21705 that looks similar issue, but i tried with 2.3.1.RELEASE version and it still does not show the values.

Example project that re-create the issue

[wilkinsona]

Thanks for the sample. The problem is as @philwebb described here. The change made in #21705 has not helped in your case as you are not using Spring Boot's launcher. This means that it doesn't get a chance to make it possible to load a manifest (which is the source of the application version) from a folder.

You can avoid the problem by unpacking the jar and then using JarLauncher to start the app:

$ java -cp . org.springframework.boot.loader.JarLauncher
DEMO BANNER START

application version           = 0.0.1-SNAPSHOT
application formatted version =  (v0.0.1-SNAPSHOT)
spring-boot version           = 2.3.1.RELEASE
spring-boot formatted version =  (v2.3.1.RELEASE)
application title             = demo-banner

DEMO BANNER END
2020-07-23 09:41:21.631  INFO 2004 --- [           main] c.e.demobanner.DemoBannerApplication     : Starting DemoBannerApplication v0.0.1-SNAPSHOT on fulcrum.local with PID 2004 (/Users/awilkinson/dev/temp/demo-banner/target/unpacked/BOOT-INF/classes started by awilkinson in /Users/awilkinson/dev/temp/demo-banner/target/unpacked)
2020-07-23 09:41:21.633  INFO 2004 --- [           main] c.e.demobanner.DemoBannerApplication     : No active profile set, falling back to default profiles: default
2020-07-23 09:41:21.992  INFO 2004 --- [           main] c.e.demobanner.DemoBannerApplication     : Started DemoBannerApplication in 0.598 seconds (JVM running for 0.866)
=== demo banner application ===

I don't think there's anything we can do to improve this behaviour. When launched with a classpath of BOOT-INF/classes and BOOT-INF/lib/*.jar the manifest isn't even on the classpath so there's no reliable way for us to find it.

Let's update the banner customization documentation to note the restriction and recommend the use of the launcher with an exploded archive.

[wilkinsona]

Another option is to set the application.version and application.title properties in application.properties. You can use placeholders to get the values from the Maven project:

application.version=@project.version@
application.title=@project.name@

[orenw1]

@wilkinsona, thank you for the answer and suggestion!

[robert-smith-911]

@wilkinsona I know this is an oldie, but mind if I update the docs for this one?

[philwebb]

Closing in favor of PR #24982. Thanks @robert-smith-911!

[wilkinsona]

Sorry for missing your question about updating the docs, @robert-smith-911. Thanks for opening a PR despite my lack of response.

[robert-smith-911]

@wilkinsona You're welcome!