Problem
I have a setup of various distinct repos/projects (i.e. app1, app2, app3) that all depend on shared functionality in my base package.
The projects also use various other third-party dependencies (i.e. app1 and app3 use spring, all of them use kotlinx-serialization).
I want to synchronise the versions of all third-party dependencies, so that any project using my base package uses the same version of every third-party dependency. However, I don't want to introduce new dependencies to projects that do not use them (i.e. app2 does not use spring)
Solution attempts
For libraries, I have been able to solve this with the help of a gradle platform, which does exactly what I want - I specify the versions in my base package, then add the platform as a dependency to my projects and can then simply add dependencies by name (i.e. implementation("org.springframework.boot:some-package")) without having to specify a version number, because it uses the provided value from my platform.
However, for plugins, I have not been able to do this. Many libraries come with plugins and naturally the plugin should be at the same version as the library. I have tried various approaches, including writing a standalone plugin, but none have worked.
Current best idea
I added implementation("org.springframework.boot:spring-boot-gradle-plugin:3.0.2") to the dependencies of my standalone plugin. Then, I added the following code to my standalone plugin:
class BasePlugin : Plugin<Project> {
override fun apply(target: Project) {
target.plugins.apply("org.springframework.boot")
}
}
This works and applies the plugin to my main project at the correct version. However, there are 2 major problems with this:
a) Now every project applies the spring plugin, including app2 (which does not use spring).
b) I have many plugins to manage and no idea how to get the long implementation-string for most of them. I found the "org.springframework.boot:spring-boot-gradle-plugin:3.0.2" by looking up the plugin-id on https://plugins.gradle.org/ and then looking at the legacy plugin application section, which sounds like I am on the wrong track.
I just want to manage the versions of plugins and libraries of multiple projects/repos in a central place - this feels like a fairly basic use case - why is this so hard?
There are some great and detailed answers about dependency management, but unfortunately none worked to perform cross-project version management for plugins.
It seems that there is no gradle functionality to do this, but I got it working with a bit of a workaround. Here is my (working) approach, in hope that it helps someone else with this:
Create a Standalone gradle Plugin
In the build.gradle.kts of the plugin, include the maven coordinates (not its ID) of every other plugin whose version you want to manage in any of your projects in the dependency block with the api keyword. i.e. api("org.springframework:spring-web:6.0.2")
In the main projects, remove every other plugin from the plugins block, so that your custom standalone plugin is the only one remaining.
Create a file (i.e. a plugins.json or whatever you want) in the project root directory of all main projects and in there supply the plugin IDs of the plugins that you actually intend to use in that project. Just the IDs, no version numbers, i.e. "org.springframework.boot" for Spring's plugin. (Keep in mind that for plugins declared as kotlin("abc") you will have to add the prefix "org.jetbrains.com.", as the kotlin method is just syntactic sugar for that)
In your plugin source code, in the overriden apply method, look for. a file named plugins.json (or whatever you chose) in the project.buildFile.parent directory (which will be the directory of the project using this plugin, NOT of the plugin itself). From this file, read the plugin IDs
for every pluginID in the file, call project.plugins.apply(id)
How/Why it works:
The main project build.gradle.kts is executed, looks at the plugin block and applies your standalone plugin (which is the only one), which calls its apply method.
This plugin then applies other plugins based on their ID from the file.
Normally, this will throw an error because these plugins are not found, but because we defined them as dependencies with the api keyword in our standalone plugin, they are now available on the classpath and in exactly the version of that import statement.
Hope it helps someone!
I use version numbers in a gradle.properties file for this purpose. Since the introduction of Gradle version catalogs, my approach is probably a bit out of date, but I'll share it here anyway. It's based on the fact that plugin versions can be managed in settings.gradle.kts by reading values from the properties file.
In gradle.properties:
springBootVersion=3.0.2
In settings.gradle.kts:
pluginManagement {
val springBootVersion: String by settings
plugins {
id("org.springframework.boot") version springBootVersion
}
}
And finally in build.gradle.kts:
plugins {
id("org.springframework.boot")
}
dependencies {
val springBootVersion: String by project
implementation(platform("org.springframework.boot:spring-boot-dependencies:$springBootVersion"))
}
Notice that the plugin version is omitted in the build script because it is already specified in the settings file.
And note also that the method for accessing the property in the settings script is slightly different from that in the build script.
a) Now every project applies the spring plugin, including app2 (which does not use spring).
It is indeed better to avoid applying too many plugins - and that's why Gradle encourages reacting to plugins.
import org.gradle.api.Plugin
import org.gradle.api.Project
import org.gradle.kotlin.dsl.*
import org.springframework.boot.gradle.plugin.SpringBootPlugin
class BasePlugin : Plugin<Project> {
override fun apply(target: Project) {
// don't apply
//target.plugins.apply("org.springframework.boot")
// instead, react!
target.plugins.withType<SpringBootPlugin>().configureEach {
// this configuration will only trigger if the project applies both
// BasePlugin *and* the Spring Boot pluging
}
// you can also react based on the plugin ID
target.pluginManager.withPlugin("org.springframework.boot") {
}
}
}
Using the class is convenient if you want to access the plugin, or the plugin's extension, in a typesafe manner.
You can find the Plugin's class by
looking in the source code for the class that implements Plugin<Project>,
in the plugin's build config for the implementationClass,
or in the published plugin JAR - in the META-INF/gradle-plugins directory there will be a file that has the implementationClass.
This doesn't help your version alignment problem - but I thought it was worth mentioning!
b) I have many plugins to manage and no idea how to get the long implementation-string for most of them. I found the "org.springframework.boot:spring-boot-gradle-plugin:3.0.2" by looking up the plugin-id on https://plugins.gradle.org/ and then looking at the legacy plugin application section, which sounds like I am on the wrong track.
You're on the right track with the "long implementation string" as you call it. I'll refer to those as the 'Maven coordinates' of the plugin.
Gradle Plugin Maven Coordinates
The plugin id of the Kotlin JVM plugin is org.jetbrains.kotlin.jvm, but the Maven coordinates are org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.0 .
The 'legacy' part refers to how the plugins are applied, using the apply(plugin = "...") syntax. The new way uses the plugin {} block, but under the hood, both methods still use the Maven coordinates of the plugin.
If you add those Maven coordinates (with versions) to your Java Platform, then you can import the platform into your project. But where?
Defining plugin versions
There are a lot of ways to define plugins, so I'll only describe one, and coincidentally it will be compatible with defining the version using a Java Platform.
If you're familiar with buildSrc convention plugins, you'll know that they can apply plugins, but they can't define versions.
// ./buildSrc/src/main/kotlin/kotlin-jvm-convention.gradle.kts
plugins {
kotlin("jvm") version "1.8.0" // error: pre-compiled script plugins can't set plugin versions!
}
Instead, plugin versions must be defined in the build config for buildSrc
// ./buildSrc/build.gradle.kts
plugins {
`kotlin-dsl`
}
dependencies {
// the Maven coordinates of the Kotlin JVM plugin - including the version
implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.8.0")
}
This looks a lot more traditional, and so I hope the next step is clean: use your Java Platform!
Applying a Java Platform to buildSrc
// ./buildSrc/build.gradle.kts
plugins {
`kotlin-dsl`
}
dependencies {
// import your Java Platform
implementation(platform("my.group:my-platform:1.2.3"))
// no version necessary - it will be supplied by my.group:my-platform
implementation("org.jetbrains.kotlin:kotlin-gradle-plugin")
}
Note that this same method will also apply if your projects an 'included build' instead of buildSrc.
Once the plugin versions are defined in ./buildSrc/build.gradle.kts, you can use them throughout your project (whether in convention plugins, or in subprojects), they will be aligned.
// ./subproject-alpha/build.gradle.kts
plugins {
kotlin("jvm") // no version here - it's defined in buildSrc/build.gradle.kts
}
I'm trying to create a multiproject using Kotlin/native and gradle in IDEA that consists of:
A backend subproject library. I want to use this library in frontend Kotlin app and also produce a native DLL that can be later used in other software. I doubt I'll need any platform specific behavior -- the most I'll interact with the system is read, write and watch a file for changes.
A frontend jvm app in Kotlin using this library as required dependency. To be more precise I'm going to write a glfw app in Kotlin that will use this lib, but that's a detail you don't have to bother with.
I want to be able to:
build DLL on it's own
build an app that depends on library and rebuilds if needed when the lib changed.
I made a hyperlink trip over gradle docs, JetBrains examples and repos but I don't quite understand how to make a multiproject like that. Can someone provide a minimal working example of such a Hello World project?
Right now this works for me in the initial stage of the project:
Use gradle init with basic type and kotlin DSL to generate a wrapper project
Add 2 modules with New > Module > Gradle > Kotlin/Multiplatform and Kotlin/JVM. That should add include("...") entries to root settings.gradle.kts At this point those modules will be empty with a single build.gradle.kts scripts
Root build.gradle.kts can be deleted - both library and app use their own
In the Multiplatform library setup at least one target for example like that:
// rootProject/library/build.gradle.kts
// ...
kotlin {
jvm() // used by jvm app
sourceSets { /*...*/ }
}
Now there should be no gradle errors and IDEA will detect the project properly - refresh gradle configuration (CTRL+SHIFT+O)
Create source directories for each module (because the modules rn): IDEA should hint the names of corresponding source sets (src/<target>/<kotlin|resources> etc.)
So now just to link the app and library together in the the app's buildscript add the implementation(project(":library")) dependency
Of course don't forget to configure the library target for example using linuxX64("native") { binaries { sharedLib {/*...*/ } } } block in kotlin plugin when trying to generate a DLL
Now it should mostly work. The structure of a project I'm working on rn looks like that:
I am trying to create a wrapper around AWS Amplify to use for my project. I have a module inside my shared ( common ) module called Amplify. Here I integrated cocoapods as instructed in the official docs. But when I try to import anything from the iosMain I keep getting Unresolved reference: cocoapods.
My project structure is as follows
Common module (shared)
|- root module
|- other features
|- amplify wrapper module
In the root module I have the
kotlin {
ios {
binaries {
framework {
baseName = "Framework"
linkerOpts.add("-lsqlite3")
export(project(":common:main"))
}
}
}
And the setup for the cocoapods in the amplify module
import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinNativeTarget
plugins {
id("multiplatform-setup") // this is from buildSrc, it adds the multiplatform plugin
id("android-setup")
id("org.jetbrains.kotlin.native.cocoapods")
kotlin("plugin.serialization") version "1.5.10"
}
version = "1.0"
kotlin {
sourceSets {
named("commonMain") {
dependencies {
}
}
}
cocoapods {
summary = "Amplify wrapper for KMP project"
homepage = "Link to a Kotlin/Native module homepage"
frameworkName = "AmplifyKMP"
pod("Amplify")
pod("AmplifyPlugins/AWSCognitoAuthPlugin")
pod("AmplifyPlugins/AWSPinpointAnalyticsPlugin")
}
}
My idea is that I'd be able to expose my wrapper from the commonMain code, that would call actual implementations from the Amplify Android and Amplify IOS libraries. My first problem is the cocoapods being unresolved and secondly all of the examples from the official docs and github all have cocoapods in the main module (root module in my case) from where they export the framework, I am not sure my approach is even feasible.
The first problem is easy. You need to add kotlin("native.cocoapods") to your plugins section.
On the second, can a sub-module import pods with cinterop and make them available to a module that depends on them? I haven't tried it. In theory the cocoapods plugin should be able to just import pods definitions to kotlin. However, the cocoapods Kotlin gradle plugin (aka kotlin("native.cocoapods")) will configure ios targets to create a framework. That might create issues with the dependency config.
In the amplify module I don't see that you're defining any iOS targets, so you'll probably need to do that, but that config will be altered by kotlin("native.cocoapods"). You'll likely need to step in and modify that yourself. You can step in and do that in gradle, but I would prepare to spend some time tweaking that.
https://github.com/touchlab/KaMPKit/blob/main/shared/build.gradle.kts#L114
Trying to figure out what I'm doing wrong. I created a small video of exactly what I'm doing in IntelliJ on Windows.
https://www.youtube.com/watch?v=nIH_55Zbxus&feature=youtu.be
And I'll describe it here in text.
Create a new project
Tick the Gradle > Kotlin/JS for browser template and untick everything else
Add implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.8' to the dependencies block in the build.gradle.
Sync the gradle files
Attempt to use something from the kotlinx.coroutines namespace
Hopefully its just a silly thing I'm missing. I expected to just have to add the coroutines library to be able to actually import it. It looks like the library is listed in the project structure for the main module so I'm not sure what else might be wrong. Here is a repo of the project too.
plugins {
id 'org.jetbrains.kotlin.js' version '1.3.72'
}
group 'org.example'
version '1.0-SNAPSHOT'
repositories {
mavenCentral()
}
dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib-js"
implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.8'
testImplementation "org.jetbrains.kotlin:kotlin-test-js"
}
kotlin.target.browser { }
You should add kotlinx-coroutines-core-js dependency. See the documentation: https://github.com/Kotlin/kotlinx.coroutines#js
I am trying to build a kotlin library for discord bots, which can be found at https://github.com/TheDrone7/discord-kt , published to jcenter (bintray link - https://bintray.com/thedrone7/discordKt/discord-kt). The library has a few dependencies of it's own as well.
When I add my own library to my test app, the library's dependencies were not installed and I started getting some errors. Is there a way to specify the library's dependencies so that they get automatically installed when a user uses my library?
EDIT: -
So basically my test app's build.gradle.kts file's dependencies section is given below
dependencies {
// Use the Kotlin JDK 8 standard library.
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
implementation("org.theDrone:discordKt:0.0.1a")
// Use the Kotlin test library.
testImplementation("org.jetbrains.kotlin:kotlin-test")
// Use the Kotlin JUnit integration.
testImplementation("org.jetbrains.kotlin:kotlin-test-junit")
}
And my library is dependent on the following packages: -
org.jetbrains.kotlinx:kotlinx-coroutines-core:1.1.0
org.java-websocket:Java-WebSocket:1.4.0
com.beust:klaxon:5.0.5
org.slf4j:slf4j-jdk14:1.7.26
now when I run my test app, it shows gives error that there is no class named WebSocketClient which is a part of the org.java-websocket:Java-WebSocket:1.4.0 package and is also the base of my entire library.
When I add the listed packages to my test app's dependencies, it works perfectly fine. So is there a way that I could define in my library that the apps using it will also automatically depend on the packages my library depends on?
You declared the Java-WebSocket library as a dependency of your library using the implementation configuration.
This configuration means: I need that for my code to work, but it's an implementation detail and it's thus not part of my public API, so users of my library won't have access to it in their compile classpath.
So Gradle, when it generates the pom.xml file for your library, adds Java-WebSocket as a runtime dependency, and not as a compile dependency.
Read the java-library plugin documentation, which explains all of that in details. Once you have understood it, use api instead of implementation in your library's build.gradle.kts file for the dependencies that are part of your API, and should thus be compile dependencies and not runtime dependencies:
api("org.java-websocket:Java-WebSocket:1.4.0")