run spring boot with kscript

I tried running

#!/usr/bin/env kscript

@file:DependsOn("org.springframework.boot:spring-boot-starter:2.0.4.RELEASE")

package my.package

import DependsOn
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.SpringApplication

@SpringBootApplication
class DummyApp

SpringApplication.run(DummyApp::class.java, *args)

it starts but fails with

ERROR org.springframework.boot.SpringApplication - Application run failed
java.lang.IllegalArgumentException: No auto configuration classes found in META-INF/spring.factories. If you are using a custom packaging, make sure that file is correct.
	at org.springframework.util.Assert.notEmpty(Assert.java:450)

A comparable groovy/@Grab script with the same setup works, so I wonder if this is something that can/will never work with kscript due to design or is just a missing feature that can be achieved … somehow

I know that running complex spring boot apps with kscript seems to be out of scope, but I have quite a experimental microservices that require minimal coding and would benefit from a scripting approach …

[holgerbrandl]

I actually love the use-case.

It’s not working for me either. It’s because we don’t use spring’s custom packaging method.

The problem seems to center around the missing META-INF/spring.factories. However, even if I patch the jar created by kscript internally to include the file, it fails with the same error. So to progress here, we’d need to find a way to provide META-INF/spring.factories via classpath. It seems partially documented under https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-developing-auto-configuration.html#boot-features-developing-auto-configuration In particular is says

Auto-configuration classes can be bundled in external jars and still be picked-up by Spring Boot.

So if we could find a way to run a spring-app without their deployment-scheme by providing an extra-jar that adds the missing META-INF/spring.factories the classpath, we could configure kscript to run it accordingly.

[holgerbrandl]

I’m not so sure. Whenever a custom build-file is required (e.g. doing something like apply plugin: 'org.springframework.boot') than we will struggle doing this in kscript, since we can not (and do not really want to) mess with the build beyond classpath and compiler settings.

I personally find it an odd design choice by the spring people to force users to use a custom build-plugin.