Netflix / Gradle Template

This project represents a template for what a Netflix OSS project should look like. We're striving for a pure Gradle build, instead of taking a consolidated plugin approach, as we would internally. This will maintain each project's isolation and keep the build as transparent as possible to the outside world. While at the same time we want to be able to push out build updates in a predictable fashion.

There are three branches for which you should concern yourself with:

• master - Template of a fully working multi-module project. It's a good starting place if you're starting from scratch.
• multi-project - Just the build files for a multi-module project.
• single-project - Just the build files for a single module project.

Choosing a branch

The goal is that projects will be able to "git merge build/branch" when changes are needed to be pushed out. If you take the wrong branch and consequently heavily modify the files, the merge will be a pain. The other advantage of using an appropriate branch is to provide a level of consistency between the projects. The master branch is best for new projects who want something working out of the gate, but after that you'd migrate to merging from the multi-project so that you don't get bad merges from the same java files. The multi-project branch is for projects which have multiple modules that will be published together, e.g. client, common and server modules. Gradle is very good at building multiple projects, but it does require slightly different syntax and isolation from the rootProject, hence the separate project. The single-project branch is the simplest build which is for a single project. All project use a Maven layout, e.g. src/main/java.

Features

The template features:

• Consolidated customizations into build.gradle, moving generic code into individual files in the gradle directory
• Jenkins friendly version of gradlew
• Able to publish to maven central
• Capable of also working with Artifactory
• Find Bugs, PMD and CheckStyle
• Build source jar and javadoc jar
• Cobertura for code coverage
• Release plugin to build, tag, and publish
• Header checking for headers

Merging build files

Merging in the build should be a four step process: merge, customize, test and delete pom.xml. In general, this is only done once and while we work out the kinks, Engineering Tools is willing to do the initial port to Gradle and provide a pull request, just contact [email protected]

Merging

This will pull in the template:

git remote add --track $BRANCH build [email protected]:Netflix/gradle-template.git
git fetch build
git merge build/$BRANCH

Customize

• Edit settings.gradle, set the name of the project and to list all the submodules you have.
• Edit gradle.properties, set the version to the next version with -SNAPSHOT on the end
• Edit build.gradle, customize ext.githubProjectName - Used to construct a few urls in the pom.
• Edit build.gradle, customize group - make sure it represents the group that you want to publish into maven/ivy with.

If in a multi-module project, edit the build.gradle and create a project block for each project, there are two by default which you override.

The dependencies will have to be changed to match the pom dependencies. In the single-project branch, simply follow the dependencies block. In the multi-project branch, there are a few dependencies sections. The first one, part of subprojects, is common to all projects. And then there's a dependency block for each project.

Delete the pom.xml

find . -name 'pom.xml' -exec git rm \{\} \;

Updating Template

As updates are put into the gradle-template project, individual OSS Projects will need to merge in those changes. Any changes will be announced to the DL Open Source Software. To perform that merge run this, using the branch you choose when you first setup the project:

git fetch build
git merge build/$BRANCH

Artifactory

By itself the above build.gradle will pull from Maven Central and publish to Maven Central, to use Netflix infrastructure we provide an "init script" to orchestrate Gradle to use artifacts.netflix.com. This pulls in artifactory.gradle, which is sourced from //depot/Tools/nebula-boot/artifactory.gradle. It's job is to:

• Set ivy cache directory to a Jenkins friendly one
• Add jfrog build-into plugin to classpath, add it as a plugin and configure it to publish to {{libs-${project.status}-local}}
• Remove all repositories
• Add artifacts.netflix.com/ext-releases-local as the only repository

Two targets available to use artifactoryi:

• uploadArtifactory - Call out to compile against internal repository
• buildWithArtifactory - Build against internal repository

Properties

Gradle has a few ways to inject properties into the project, which can then be used in the DSL. It can done on the command line via the "-P option, e.g. ./gradlew -Pmyproperty=myvalue". It can also be done via Java System Property as long as it's prefixed with ORG_GRADLE_PROJECT, e.g. ./gradlew -DORG_GRADLE_PROJECT_myproperty=myvalue. To avoid having to pass in some properties every time on the command line, they can be stored in $HOME/.gradle/gradle.properties.

When publishing to Maven Central, we need a few "secrets" to sign the artifacts and to log into Sonatype. Most of these are handled by the [OSS Jenkins] page. If you had to release from your desktop, the best way to store these is to create this file in your home directory, with the appropriate values:

signing.secretKeyRingFile = /Users/yourUserName/.gnupg/secring.gpg
signing.keyId = 740A1840
signing.password = youShouldSetThis
sonatypeUsername = jiraSonaTypeUser
sonatypePassword = CTheTrees