Develop Reference

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'

Unable to use outside dependencies within custom gradle plugin implementation

When attempting to use outside dependencies within a custom gradle plugin I'm building, I am not able to import or use them in any regard.
I've attempted to specify in both the build script and the normal dependencies closure my dependencies. I'm using Gradle 5.5 (wrapper script) and I am using the buildSrc method of writing a custom gradle plugin.
// Necessary if loading custom plugins
apply plugin: 'java-gradle-plugin'
buildscript {
repositories {
mavenCentral()
jcenter()
}
dependencies {
classpath 'com.google.code.gson:gson:2.8.5'
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
group 'com.foo'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
jcenter()
}
gradlePlugin {
plugins {
greeterPlugin {
id = 'com.foo.dbcreation-plugin'
implementationClass = 'com.foo.dbcreation.DbCreation'
}
}
}
dependencies {
compile 'com.google.code.gson:gson:2.8.5'
}

There are quite a few issues I see here.
buildscript does not control the dependencies for your plugin implementation.
Use the plugins {} DSL block to apply plugins. It is the preferred way: https://docs.gradle.org/current/userguide/plugins.html#sec:plugins_block
Should be using implementation over compile since compile is deprecated as noted in https://docs.gradle.org/current/userguide/java_plugin.html#tab:configurations
With that said, your Gradle file should be like:
plugins {
id 'java-gradle-plugin'
id 'eclipse'
id 'idea'
}
group 'com.foo'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
jcenter()
}
gradlePlugin {
plugins {
greeterPlugin {
id = 'com.foo.dbcreation-plugin'
implementationClass = 'com.foo.dbcreation.DbCreation'
}
}
}
dependencies {
implementation 'com.google.code.gson:gson:2.8.5'
}

I figured out what my issue was. For projects being built using the buildSrc directory, you need to have the build.gradle file reside in that directory instead of the root project directory (where the build.gradle normally lives). I just converted the project to a normal gradle project and it works just fine.

Using protobuf with Gradle (IntelliJ)

I am trying to generate code for a simple protobuf example using the build instructions given here. I have been trying for awhile but I am not able to see any auto generated code in my source root.
The following is my build.gradle file
buildscript {
ext {
springBootVersion = '2.0.4.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
classpath "io.spring.gradle:dependency-management-plugin:1.0.3.RELEASE"
classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.5'
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
apply plugin: 'com.google.protobuf'
group = 'io.ai.vivid'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencyManagement {
imports {
mavenBom 'com.amazonaws:aws-java-sdk-bom:1.11.228'
}
}
protobuf {
protoc {
artifact = "com.google.protobuf:protoc:3.5.1-1"
}
generateProtoTasks.generatedFilesBaseDir = 'generated-sources'
plugins {
grpc {
artifact = 'io.grpc:protoc-gen-grpc-java:1.14.0'
}
}
generateProtoTasks {
all()*.plugins {
grpc {}
}
}
}
dependencies {
compile 'io.grpc:grpc-netty-shaded:1.14.0'
compile 'io.grpc:grpc-protobuf:1.14.0'
compile 'io.grpc:grpc-stub:1.14.0'
}
Also in my build.gradle file IntelliJ complains that it cannot resolve name protobuf
Things I have tried
Sync gradle tool in IntelliJ. This is the most prominent solution
given in SO
Setting Build tools -> Gradle -> Runner -> Delelgate IDE build/run
actions on gradle to true
Clean rebuilding of the gradle project.
From my understanding of the GitHub post, when you use the protobuf plugin, the stub will be automatically generated for you. What am I missing?

You've applied idea plugin, but you didn't configure it. You need to tell idea plugin where to include the generated source code.
protobuf {
generatedFilesBaseDir = "$projectDir/src/generated"
}
idea {
module {
sourceDirs += file("${projectDir}/src/generated/main/java");
sourceDirs += file("${projectDir}/src/generated/main/grpc");
}
}
You can take a look
at a full example of a buildfile here: build.gradle

In case anyone else ends up here problems getting IntelliJ to recognise the generated sources (Red highlight imports , classes etc). Beware of the intellisense file size limit. If your generated protobuf code exceeds the default setitng of 2500KB then the file is ignored.
Got Help -> Edit custom properties and add an entry appropriate for your case e.g.
idea.max.intellisense.filesize=4000
Spent half a day faffing over different source set source folder, generated sources, and include / exclude directories. Turned out I just need to increase this value

Alternatively, you can use sourceSets:
sourceSets {
main {
java {
srcDirs 'build/generated/source/proto/main/grpc'
srcDirs 'build/generated/source/proto/main/java'
}
}
}

Unable to Build Spring RestService Tutorial in IntelliJ

I am attempting to work through the Spring Framework Restful Web Service creation tutorial(https://spring.io/guides/gs/rest-service/#scratch) using Gradle and IntelliJ. I have followed everything to the letter but being fairly new to Spring, IntelliJ, and Java in general I'm unsure how to go about further debugging my issue.
When I attempt to build my project I receive a few errors stating "Java: package org.springframework.web.bind.annotation does not exist." I'm guessing I'm missing a library reference but am unsure how to check and include it.
buildscript {
ext {
springBootVersion = '1.3.5.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
classpath("org.springframework:spring-web:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
jar {
baseName = 'hello_springtest'
version = '0.0.1-SNAPSHOT'
}
repositories {
mavenCentral()
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
task wrapper(type: Wrapper) {
gradleVersion = '2.3'
}
eclipse {
classpath {
containers.remove('org.eclipse.jdt.launching.JRE_CONTAINER')
containers 'org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8'
}
}
Just thought I'd add some additional information. I'm still seeing the errors and am unsure why but my project does report that the build was successful. When I attempt to make the project however that's when I receive the annotation does not exist error.

You have some dependency in your builds script, which seems to me redundant and causes Gradle to look up for additional dependencies.
Just remove this dependency from your buildscript dependencies
classpath("org.springframework:spring-web:${springBootVersion}")
I see no reason to use it within your buildscript.

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.