Gradle building Spring Boot library without Main Class - java

I am trying to build a Spring Boot/Gradle project and create a jar without a main class. My purpose is that this project is a library that will be pulled in by other projects therefore the library project does not require a main class to run. Unfortunately, no matter what kind of gradle config I write I keep getting errors when I try to build install about not having a main class or not being able to find the bootJar task.
Here's what my gradle file looks like:
plugins {
id 'org.springframework.boot' version '2.1.7.RELEASE' apply false
}
apply plugin: 'io.spring.dependency-management'
apply plugin: 'maven'
dependencyManagement {
imports {
mavenBom org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES
}
}
repositories {
mavenCentral()
}
jar {
enabled = true
}
bootJar.dependsOn fooTask
But when I run this I get the following error:
Could not get unknown property 'bootJar' for root project
'foo-library' of type org.gradle.api.Project.
What in my configuration needs to change?

Disable bootJar in your build.gradle
bootJar {
enabled = false
}

Related

Gradle - "unable to resolve class" for spring boot managed project dependencies

With the following gradle file within a multi project or multi module build, (lets call it web)
plugins {
id 'groovy'
id 'org.springframework.boot'
id 'io.spring.dependency-management'
}
dependencies {
implementation "org.codehaus.groovy:groovy:2.5.14"
implementation(project(':persistence'))
}
I'm unable to resolve the class files present in the project 'persistence' and get the following error while compiling
unable to resolve class XXX
This is the gradle file of the 'persistence' module
plugins {
id 'groovy'
id 'org.springframework.boot'
id 'io.spring.dependency-management'
}
dependencies {
implementation "org.codehaus.groovy:groovy:2.5.14"
}
What could be the problem?
Also, here is the settings.gradle and directory structure
// settings.gradle
pluginManagement {
plugins {
id 'org.springframework.boot' version "2.3.3.RELEASE"
id 'io.spring.dependency-management' version '1.0.10.RELEASE'
}
}
dependencyResolutionManagement {
repositories {
mavenCentral()
}
}
rootProject.name = 'gradle-bug'
include 'commons'
include 'persistence'
include 'security'
include 'web'
When gradle sees a "implementation" dependency on a project, it uses the jar of that dependency for compilation.
When you add the org.springframework.boot plugin, it by default disables the jar creation task for that module, but gradle continues to depend on that jar for its compilation, even though the classes of that module have been generated in the build/classes folder.
To fix this, you have to enable the jar creation by adding the following snippet to the persistence module
jar {
enabled = true
}

How do you parameterize the Spring Boot Gradle plugin?

We are looking to migrate from Maven to Gradle, and have worked through most of the challenges you would expect for replacing the parent POM concept. There is one sticky point that we haven't figured out yet. We need to specify the version of Spring Boot we are using globally, but I run into invalid build file problems with both of the solutions I've tried:
I tried putting the plugins { id 'org.springframework.boot' version '2.1.17.RELEASE' } declaration in the common build script. Build error, "Only Project and Settings build scripts can contain plugins {} blocks."
I tried calling the common build file to specify the springBootVersion parameter and using that in the plugins declaration. Build Error, "only buildscript {} and other plugins {} script blocks are allowed before plugins {} blocks, no other statements are allowed"
All of this would be easier if I could simply apply plugin: 'org.springframework.boot' but then Gradle can't find the plugin. All but one microservice are on a single version of Spring Boot, and we want to be able to upgrade globally if possible.
Additional Information
I have ~40 microservices plus some libraries used by those services
Separate repository for each of them, so the normal parent/child approach does not work
Maven parent POMs allowed you to publish that POM as it's own resource, and there is no 1:1 equivalent feature in Gradle
Gradle pluginManagement concept also doesn't work for us because it resolves the Spring Boot plugin but the dependency management plugin now can't be found.
My common build script is included here:
repositories {
mavenLocal()
/* Removed our internal repositories */
jcenter()
mavenCentral()
}
apply plugin: 'java'
apply plugin: 'jacoco'
apply plugin: 'maven-publish'
apply plugin: 'io.spring.dependency-management'
group = 'nedl-unified-platform'
/* Required to publish Spring Boot microservices to publish to repository */
configurations {
[apiElements, runtimeElements].each {
it.outgoing.artifacts.removeIf { it.buildDependencies.getDependencies(null).contains(jar) }
it.outgoing.artifact(bootJar)
}
}
java {
sourceCompatibility = JavaVersion.VERSION_11
targetCompatibility = JavaVersion.VERSION_11
withJavadocJar()
withSourcesJar()
}
ext {
set('springBootVersion', '2.1.17.RELEASE')
set('springCloudVersion', "Greenwich.SR6")
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
}
}
jacoco {
toolVersion = "0.8.5"
reportsDir = file("$buildDir/reports/jacoco")
}
test {
finalizedBy jacocoTestReport // report is always generated after tests run
}
jacocoTestCoverageVerification {
violationRules {
rule {
limit {
minimum = 0.2
}
}
}
}
jacocoTestReport {
dependsOn test // tests are required to run before generating the report
reports {
xml.enabled true
html.destination file("${reportsDir}/jacocoHtml")
xml.destination file("${reportsDir}/jacocoReport.xml")
}
}
tasks.withType(JavaCompile) {
options.encoding = 'UTF-8'
}
publishing {
publications {
maven(MavenPublication) {
from components.java
}
}
repositories {
/* excluded for privacy and brevity's sake, our internal Maven repo */
}
}
And that is called by our project build script that I want to parameterize:
plugins {
id 'org.springframework.boot' version springBootVersion
}
apply from: "https://mycentral.repo/project-common/develop/build.gradle"
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-server'
implementation 'ch.qos.logback:logback-classic'
implementation 'javax.annotation:javax.annotation-api:1.3.2'
implementation 'javax.xml.bind:jaxb-api:2.4.0-b180830.0359'
implementation 'org.glassfish.jaxb:jaxb-runtime:2.4.0-b180830.0438'
testImplementation 'org.springframework.boot:spring-boot-starter-test'
}
version = '0.0.2-SNAPSHOT'
I think the gap here is that in maven you have the concept of a parent pom, whereas in Gradle you don't. There is no 1:1 mapping to this like you say, but you can have plugins in Gradle, and apply a plugin.
The closest thing you would have is if you developed your own Gradle plugin, which each of your projects could apply. Your custom plugin would then configure Spring Boot among whatever else is common to all your projects. This plugin would define the version of Spring Boot you want all your other projects to use.
You wouldn't get much benefit to a custom plugin if it's only concern is configuring Spring Boot, it would need to do other things as well. It can be difficult to create a Gradle plugin when you don't have allot of experience in it. You lose all the familiar syntax to the build.gradle and you literally have to write code, (there are some similarities but I have found it difficult), I would avoid it if possible.
I would suggest you start off by applying the spring boot plugin directly to one of your microservices projects, get that working, then do another. After you have done a number of them you will then be able to see what is common between them, and if it is indeed worth investing into developing a global plugin. You really need to be careful though because your global plugin has the potential to be both a blessing and curse. It may take away allot of manual work for maintainers, but if you get it wrong it will cause them grief, and then they will want to go back to maven.
I'm not sure if I understand your globally defined Spring version requirement. Unless you are using SNAPSHOT dependencies/plugins (bad don't do that), (or a black magic settings.gralde outside of your repo), you will have to put some version somewhere. As an alternative you could create your own custom task which runs on the check lifecycle which will check the version of spring (or your plugin) and print a warning if it's not the latest version, and encourage the developer to upgrade.
Extra Info
Parameterizing plugins with properties can be done putting your property in gradle.properties as springBootVersion=2.1.17.RELEASE .
I'm not sure I understood your issue perfectly but you should use the Gradle way for sharing configuration : the root project config.
Instead of including the common build script in every project, create a global project and set the configuration here.
root
|
| --- projectA
| --- projectB
| --- projectC
With the according settings.gradle
include 'projectA'
include 'projectB'
include 'projectC'
In the root build.gradle, set up the version
ext.springBootVersion = '2.1.17.RELEASE'
In subprojects using springBoot, let's say projectB, apply the plugin in the sub build.gradle
buildscript {
repositories {
jcenter()
mavenCentral()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:$springBootVersion"
}
}
apply plugin: 'org.springframework.boot'
This example works for me, though I may not understand all of the constraints.
If we abstract the version of Spring Boot behind a fixed URI (e.g. on an internal CI/CD server), then consider this in each project/repo's build.gradle:
buildscript {
repositories {
jcenter()
}
def SPRING_BOOT_VERSION_URI = 'http://localhost:5151/api-server/spring-boot.txt'
ext.springBootVersion = new URL(SPRING_BOOT_VERSION_URI).getText().trim()
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:$springBootVersion"
}
}
apply plugin: 'org.springframework.boot'
apply from: "../common/build.gradle"
I realize the original question states that the apply plugin doesn't work, but it's not clear to me if that precludes this method.
Finally, note that it is easy to expand this beyond a simple text-file to be a more formal JSON specification (tailored to the teams' needs).
If you add this to the root project, all child projects should be able to just import from the same set of Spring Boot dependencies. The magic ingredient is the allprojects block:
buildscript {
repositories {
maven { url "https://plugins.gradle.org/m2/" }
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
ext {
springBootVersion = '2.3.4.RELEASE'
}
allprojects {
apply plugin: 'java'
apply plugin: 'io.spring.dependency-management'
dependencyManagement {
imports {
mavenBom("org.springframework.boot:spring-boot-dependencies:${springBootVersion}")
}
}
}
apply plugin: 'org.springframework.boot'

Spring boot where is my jar file

Spring boot makes it really easy to setup a simple app.
But it takes me longer to actually get a jar file which I can upload to a remote server.
I am using IntelliJ, no command line, and I use gradle. The application is running somehow out of Intellij. But where are the created files? Where is my jar from Bootjar?
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:2.0.0.RELEASE")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
bootJar {
baseName = 'gs-spring-boot'
version = '0.1.0'
}
repositories {
mavenCentral()
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
dependencies {
compile("org.springframework.boot:spring-boot-starter-web")
compile("org.springframework.boot:spring-boot-starter-actuator")
testCompile("org.springframework.boot:spring-boot-starter-test")
// add spring data repos
compile("org.springframework.boot:spring-boot-starter-data-jpa")
compile("org.postgresql:postgresql:42.2.4")
// REST interface
compile("org.springframework.boot:spring-boot-starter-data-rest")
// Security
compile("org.springframework.boot:spring-boot-starter-security")
}
Update: Added a picture of the project structure:
Update 2: Folder structure:
There will not be a jar created if you are just running this in your IDE. In order to do that, you need to run the gradle build (in your case) either from your IDE or the command line to get it to build it into a jar.
From the command line, go to your project directory and type this:
./gradlew build
This executes the gradle wrapper, which should download everything you need to run the build, and then executes the build.
You will then find your jar in build/lib
build/libs (if you've ran build to build the jar file)

Creating task in Gradle + Spring Boot to set default profile?

I just want to set the default profile when I run gradleRun, but this is failing with cannot find method run()
I'm first wondering:
What does the buildscript do for me and how can I successfully use the spring-boot plugin
Could not find method bootRun() for arguments [build_74d21ufxy8p9tyrqny7v4pkut$_run_closure1#389a9e15] on root project 'core' of type org.gradle.api.Project.
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "org.springframework.boot:spring-boot-gradle-plugin:2.0.1.RELEASE"
}
}
task local {
run { systemProperty "spring.profiles.active", "development" }
}
bootRun.mustRunAfter local
apply plugin: 'java'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'maven'
apply plugin: 'spring-boot'
group = 'com.remindful'
version = '1.0.0-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
Remove
task local {
run { systemProperty "spring.profiles.active", "development" }
}
bootRun.mustRunAfter local
Add
bootRun {
systemProperty "spring.profiles.active", "development"
}
To answer your questions about build script and spring-boot plugin, build script contains the tasks needed to build a project using gradle, this is simplistic description, check the documentation. Spring boot plugin
allows you to package executable jar or war archives, run Spring Boot applications, and use the dependency management provided by spring-boot-dependencies
You can refere to the documentation here

How to compile project with Google Checkstyle rules with gradle?

I am trying to use Google checkstyle configuration (https://github.com/checkstyle/checkstyle/blob/master/src/main/resources/google_checks.xml) but I am constantly getting an error on gradle check:
Unable to create a Checker: cannot initialize module TreeWalker - Unable to instantiate EmptyCatchBlock
I used Gradle to build the project. Below is my gradle.build.
apply plugin: 'java'
apply plugin: 'idea'
apply plugin: 'checkstyle'
sourceCompatibility = 1.8
version = '1.0'
checkstyle {
toolVersion = "6.3"
}
task "create-dirs" << {
sourceSets*.java.srcDirs*.each { it.mkdirs() }
sourceSets*.resources.srcDirs*.each { it.mkdirs() }
}
jar {
manifest {
attributes 'Implementation-Title': 'xyz',
'Implementation-Version': 0.01
}
}
repositories {
mavenCentral()
}
dependencies {
compile (
['org.apache.logging.log4j:log4j-api:2.2'],
['org.apache.logging.log4j:log4j-core:2.2']
)
testCompile(
['junit:junit:4.11'],
['org.mockito:mockito-core:1.+']
)
}
test {
systemProperties 'property': 'value'
}
uploadArchives {
repositories {
flatDir {
dirs 'repos'
}
}
}
Also, when I try to add XML config file to Checkstyle plugin in IDEA I get similar error but with a stack trace:
org.infernus.idea.checkstyle.exception.CheckStylePluginException: <html><b>The CheckStyle rules file could not be loaded.</b><br>cannot initialize module TreeWalker - Unable to instantiate EmptyCatchBlock</html>
at org.infernus.idea.checkstyle.checker.CheckerFactory.blacklistAndShowMessage(CheckerFactory.java:234)
at org.infernus.idea.checkstyle.checker.CheckerFactory.createChecker(CheckerFactory.java:188)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getOrCreateCachedChecker(CheckerFactory.java:98)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getChecker(CheckerFactory.java:73)
at org.infernus.idea.checkstyle.checker.CheckerFactory.getChecker(CheckerFactory.java:41)
I cannot figure out what am I doing wrong. Any help would be appreciated.
Gradle version: 2.2
You can add this configuration into your build.gradle file:
configurations {
checkstyleOverride
}
dependencies {
checkstyleOverride('com.puppycrawl.tools:checkstyle:6.11.2')
}
tasks.withType(Checkstyle) {
checkstyleClasspath = project.configurations.checkstyleOverride
}
Enjoy!
The problem lies in the fact that com.puppycrawl.tools.checkstyle.checks.blocks.EmptyCatchBlockCheck was indeed added to checkstyle but for version 6.4-SNAPSHOT. As it can be seen in checkstyle repository (pom.xml history) version 6.4-SNAPSHOT was introduced on the 02.02.2015 and EmptyCatchBlockCheck class was created on 18.02.2015.
Gradle still uses version 6.3 as in the following log extract:
:checkstyleMain
Download https://repo1.maven.org/maven2/com/puppycrawl/tools/checkstyle/6.3/checkstyle-6.3.pom
So there's simply no class You'd like to use.
According to the docs checkstyle classpath can be specified with checkstyleClasspath property - you can try to set it up manually.
I've also prepared a demo with 6.4-SNAPSHOT version, it can be found here. Checkstyle jar was built with mvn clean package with source taken from this repo.
Here is an approach that works with the (currently) latest versions of Gradle & Checkstyle (Gradle 6.1.1 & Checkstyle 8.29):
plugins {
id 'java'
id 'checkstyle'
}
configurations {
checkstyleConfig
}
dependencies {
checkstyleConfig("com.puppycrawl.tools:checkstyle:8.29") { transitive = false }
}
checkstyle {
toolVersion '8.29'
config = resources.text.fromArchiveEntry(configurations.checkstyleConfig, 'google_checks.xml')
}
Note that the Checkstyle dependency excludes transitive dependencies, otherwise the resources.text.fromArchiveEntry will fail since multiple JAR files will be present, and it will be unable to select a single one.

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