I am trying to learn gradle from this site but I do not know how to add a source for 3rd party libraries. Should I add the following to the build.gradle file?
apply plugin: 'java'
repositories {
mavenCentral()
}
dependencies {
compile "joda-time:joda-time:2.2"
}
jar {
baseName = 'gs-gradle'
version = '2.3'
}
I recommend learning gradle from their official site which contains more comprehensive documentation than the Spring site. After grasping the basics of gradle you can venture into using gradle for a Spring project as it adds complexity on top of plain gradle especially when using the Spring boot plugin.
In order to add dependencies to a (Java) project you have to get the GAV coordinates (GroupId:ArtifactId:Version). These can be obtained from the project websites or directly from the public (maven) repositories. The popular jCenter() and mavenCentral() are already build in.
Definining a repository is done using the repositories block:
repositories {
mavenCentral()
}
Then you have to specify to which Configuration you want to add you dependency; the following snippet adds joda-time to the build-in compile configuration which means that it will be added to the compile classpath:
dependencies {
compile "joda-time:joda-time:2.2"
}
So yes, your script is correct for adding the joda-time library but it might be a good idea to delve further into the gradle documentation to understand what it does.
Related
Can someone explain to me how depedencies listed in the "buildscript" in the build.gradle file are different than regular dependencies listed in the dependencies block { } ? and why they have to be listed with the syntax "implementation"? I've googled this and responses say the dependencies in the buildscript and used to "build the project" but I don't understand this? can anyone give a more clear picture and answer?
buildscript:
buildscript
{
repositories
{
maven {
url 'myMavenFeed'
credentials {
username "myUsername"
password myPassword
}
}
mavenCentral()
jcenter()
}
dependencies
{
classpath "com.microsoft.azure.sdk.iot:iot-device-client:1.14.1"
}
}
Dependencies block:
dependencies
{
compile group: 'com.microsoft.azure.sdk.iot', name: 'iot-device-client', version: '1.16.0'
}
Can someone explain to me how depedencies listed in the "buildscript" in the build.gradle file are different than regular dependencies listed in the dependencies block { } ?
Dependencies defined in the buildscript { } block are dependencies to use to build your project. These dependencies are available to use in your Gradle build file (build.gradle or build.gradle.kts)
Dependencies defined in the dependencies { } are for your application code.
So for your samples in your questions, does it make sense for Gradle (the build system) to have iot-device-client on its classpath? Why does a build system need iot-device-client on its classpath to build your project? It doesn't make sense therefore it should be removed.
Now let's say you are developing an application the requires some functionality or class from iot-device-client. You need a way to add this library to your application's code/classpath. You when then declare it as a dependency as you have done above:
dependencies {
implementation("com.microsoft.azure.sdk.iot:iot-device-client:1.16.0")
}
References:
External dependencies for the build script
Declaring depenedncies
and why they have to be listed with the syntax "implementation"?
implementation is known as a configuration: A Configuration represents a group of artifacts and their dependencies
There are many more configurations depending on the plugins you apply to your project. For example, if you apply the Java plugin:
plugins {
id("java")
}
The following configurations are available to use:
implementation
compileOnly
compileClasspath
...and many more
Each one has their own meaning/usage and I strongly suggest reading about them here.
I work on a project with multiple grails services, plugins and libraries, all built with gradle with their dependencies declared in build.gradle files, one per project, this makes sense, I hope.
In maven I used to be able to declare versions of all dependencies in one parent project pom, or a pom template, and only include the dependencies in the projects that required them without the versions. This made upgrading dependencies easy in one place. Is there a simple way to do this in gradle?
Pseudocode example:
master_template/build.gradle
dependencies {
joda-time:joda-time:2.9.1
cglib:cglib:3.2.9
javax.servlet:javax.servlet-api:3.1.0
}
service_a/build.gradle
parent: master_template
dependencies {
joda-time:joda-time
javax.servlet:javax.servlet-api
}
service_b/build.gradle
parent: master_template
dependencies {
cglib:cglib
javax.servlet:javax.servlet-api
}
You can create a multi module project like you would do in maven with a parent pom.
In order to manage the dependency in the parent, I use the spring dependency management plugin.
You parent build.gradle would look like:
subprojects {
apply plugin: "io.spring.dependency-management"
sourceCompatibility = 1.8
targetCompatibility = 1.8
check.dependsOn dependencyCheckAggregate
repositories {
mavenLocal()
jcenter()
// other repos
}
dependencyManagement {
def jacksonVersion = "2.+"
dependencies {
dependency "com.fasterxml.jackson.core:jackson-annotations:$jacksonVersion"
dependency "com.fasterxml.jackson.core:jackson-core:$jacksonVersion"
dependency "com.fasterxml.jackson.core:jackson-databind:$jacksonVersion"
dependency "com.fasterxml.jackson.datatype:jackson-datatype-jdk8:$jacksonVersion"
dependency "com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:$jacksonVersion"
}
}
}
Now, you can add dependencies to your submodules without specifying version.
You can easily achieve what you want by using Gradle's default apply from: 'other.gradle', so no additional plugins are needed.
In my micro-service project I'm using something like that:
common-gradle/env.gradle
apply plugin:'groovy'
ext.compile = [ 'joda-time:joda-time:2.9.1', 'cglib:cglib:3.2.9` ]
ext.testCompile = [ 'org.spockframework:spock-core:1.3-groovy-2.5' ]
common-gradle/dependencies.gradle
dependencies {
compile ext.compile
testCompile ext.testCompile
}
And the usage
service_a/build.gradle
apply from:'../common-gradle/env.gradle'
ext.compile << 'ch.qos.logback:logback-classic:1.2.3'
apply from:'../common-gradle/dependencies.gradle'
Thus each of my build.gradle files contain only 3-5 lines of critical information like project name and version.
You don't need to import the common-gradle as a project in your IDE, you can simply use symlinks to avoid using external references. Also during build on a Jenkins-like pipeline, the only thing you have to do is to check out the common-gradle repo into your working dir.
In our company, many of the different projects use similar technology stack and will have many common features.
So, we want to maintain the common features, dependencies etc. in one common file and refer it in the other projects.
In maven, it is something like creating a separate maven project with the common dependency information and refer that in the other projects as .
I want to do something similar to the maven parent project in gradle, which can be used by all different projects.
I googled for that, but could not find a concise information on how to do that.
We are not allowed to use external thirdparty plugins.
It would be great if someone could explain it how to do that.
in gradle you can do that, but for it you need to have external plugin, otherwise it is not possible at least for now. I have achieved it in this way:
buildscript {
repositories { jcenter() }
dependencies {
classpath 'com.netflix.nebula:nebula-dependency-recommender:4.3.0'
}
}
allprojects {
apply plugin: 'nebula.dependency-recommender'
apply plugin: 'groovy'
apply plugin: 'java'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
mavenCentral()
jcenter()
maven { url "http://repo1.maven.org/maven2/" }
maven { url "REPOSITORY_OF_YOUR_PARENT_POM.XML" }
}
dependencyRecommendations {
mavenBom module: 'YOUR_PARENT_POM_GROUP:YOUR_PARENT_POM_ID:YOUR_PARENT_POM_VERSION'
}
}
where:
REPOSITORY_OF_YOUR_PARENT_POM.XML - any system like nexus or something else accessible for maven
YOUR_PARENT_POM_GROUP - your parent pom project group (e.g. com.foo.bar.parent)
YOUR_PARENT_POM_ID - your parent pom id (e.g. projects-parent)
YOUR_PARENT_POM_VERSION - your parent pom project version (e.g. 1.0.1)
so, if the external dependency to netflix.nebula is fine , than you can go in this way
Gradle has many extension mechanisms for leveraging build logic located outside of the main script.
A simple thing that can be done is to use an external build script, which can be sourced from the local file system or through an URL, see the documentation on this topic.
If that solution gets too problematic, then you can move to packaging a real plugin that others can apply and potentially configure.
This will allow you to configure much more than dependencies for example.
I want to write a Gradle script to download a JAR file from Maven and combine it with some other resources to create an RPM file using the nebula.ospackage plugin.
I can't declare the dependency using the compile configuration as it is not available without using the java plugin (and it also doesn't make sense to use compile as I am not compiling anything).
Is there a type of dependency I can use for this purpose?
Or am I required to use the java plugin?
As far as I understood java plugin will not be required. Please have a look a the script below - you can define custom configuration and use it in build script. As you can see, java plugin is not applied:
repositories {
mavenCentral()
}
configurations {
lol
}
dependencies {
lol 'junit:junit:4.12'
}
task cp(type: Copy) {
from configurations.lol
into ('lol')
}
When writing a gradle plugin, is it possible to add dependencies to the compile and testCompile classpath for projects that apply the plugin?
If so, is there a simple example that you can reference?
As an example; let's say I wanted to write a plugin that, among other things, added the AWS Java API jars to a project i.e. I get the the jars on the classpath of the project where I apply the plugin allowing me to compile against them.
Thanks
I am not fully sure I understand the question but you can look at the gradle war plugin (https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/groovy/org/gradle/api/plugins/WarPlugin.java) which defines new tasks providedCompile which extends compile
Edit : making plugin with its dependencies
In your example, its totally possible that the plugin defines its own dependencies like in a normal build.gradle file
repositories {
mavenCentral()
}
dependencies {
compile "com.amazonaws:aws-java-sdk-ec2:1.10.2"
}
see for example the was plugin (https://github.com/classmethod-aws/gradle-aws-plugin/blob/develop/build.gradle) when you apply this plugin in your own build the aws dependencies will be downloaded and available to your build.