creating springboot gradle multi-module library project using plugins DSL and a convention plugin that reside in buildSrc

Question

I am trying to build multi module gradle library. I am trying to follow what I read in offical documentation. I am working in company which has its own nexus repository for spring and other libraries

My project structure is as follows multi-project

├── libA
│ └── build.gradle
├── libB
│ └── build.gradle
├── buildSrc
│ └── build.gradle
└── main/src/groovy
└────────multiproject.common-conventions.gradle
│ └── settings.gradle

The project involves using spring boot for different library, and the dependencies are almost the same. Here was my attempt that is not working

buildSrc/build.gradle

plugins { 
    id 'groovy-gradle-plugin' 
} 

repositories { 
    gradlePluginPortal() 
}

buildSrc/multiproject.common-conventions.gradle

plugins { 
    id 'java-library' 
    id 'maven-publish' 
    id 'org.springframework.boot' 
} 
repositories { 
    mavenCentral()
} 
dependencies { 
     implementation group: 'org.springframework.boot:spring-boot-gradle-plugin'
      implementation 'org.springframework.boot:spring-boot-starter' 
      implementation 'org.springframework.boot:spring-boot-starter-aop' 
      implementation 'org.springframework.ws:spring-ws-core' 
      implementation 'org.apache.httpcomponents:httpclient:4.5.13' 
      implementation 'org.springframework.retry:spring-retry:1.3.1' 
      implementation 'javax.cache:cache-api:1.1.1' 
      implementation 'org.ehcache:ehcache:3.10.0' 
      implementation 'com.fasterxml.jackson.core:jackson-databind:2.13.3' 
      testImplementation 'org.springframework.boot:spring-boot-starter-test' 
}

 tasks.named('test') { 
    useJUnitPlatform()
 }

now I try to use above plugin in one sub modules, let say libA libA/build.gradle

plugins { 
id("multiproject.common-conventions")
id 'org.springframework.boot' version
}

I get the following exception

 org.gradle.api.plugins.UnknownPluginException: Plugin with id 'org.springframework.boot' not found.

when I add the version to 2.6.4 I get Invalid plugin request [id: 'org.springframework.boot', version: '2.7.1']. Plugin requests from precompiled scripts must not include a version number. Please remove the version from the offending request and make sure the module containing the requested plugin 'org.springframework.boot' is an implementation dependency. Invalid plugin request [id: 'org.springframework.boot', version: '2.7.1']. Plugin requests from precompiled scripts must not include a version number. Please remove the version from the offending request and make sure the module containing the requested plugin 'org.springframework.boot' is an implementation dependency.

How can I setup multi module gradle library to use common-conventions plugin using the buildSrc folder, and the plugins DSL? I am using gradle 7.3 version.

Answer 1

Have a look at this section of Gradle's doc https://docs.gradle.org/current/userguide/custom_plugins.html#applying_external_plugins_in_precompiled_script_plugins . As stated there, in order to apply an external plugin (spring-boot-gradle-plugin in your case) in a precompiled script plugin (your multiproject.common-conventions.gradle), it has to be added to the plugin project's implementation classpath in the plugin's build file (you're buildSrc/build.gradle file)

buildSrc/build.gradle

plugins {
  id 'groovy-gradle-plugin'
}

repositories {
  mavenCentral()
}

dependencies {
  implementation('org.springframework.boot:spring-boot-gradle-plugin:3.0.0')
}