I'm trying to achieve a simple scenario in my spring boot project build: including / excluding dependencies and packaging war or jar depending on the environment.

So for example, for the environment dev include devtools and package jar, for prod package war etc.

I know it is not XML based configuration anymore and I can basically write if statements in my build.gradle but is there a recommended way of achieving this?

Can I declare some common dependencies and refer them in a single file instead of creating multiple build files?

Is there a best practice changing build configuration based on the build target environment?


ext {
    devDependencies = ['org.foo:dep1:1.0', 'org.foo:dep2:1.0']
    prodDependencies = ['org.foo:dep3:1.0', 'org.foo:dep4:1.0']
    isProd = System.properties['env'] == 'prod'
    isDev = System.properties['env'] == 'dev'
}

apply plugin: 'java'

dependencies {
    compile 'org.foo:common:1.0'
    if (isProd) {
       compile prodDependencies
    }
    if (isDev) {
       compile devDependencies
    }
}

if (isDev) tasks.withType(War).all { it.enabled = false }

My version (inspired by Lance Java's answer):

apply plugin: 'war'

ext {
  devDependencies = {
    compile 'org.foo:dep1:1.0', {
      exclude module: 'submodule'
    }
    runtime 'org.foo:dep2:1.0'
  }

  prodDependencies = {
    compile 'org.foo:dep1:1.1'
  }

  commonDependencies = {
    compileOnly 'javax.servlet:javax.servlet-api:3.0.1'
  }

  env = findProperty('env') ?: 'dev'
}

dependencies project."${env}Dependencies"
dependencies project.commonDependencies

if (env == 'dev') {
  war.enabled = false
}

Sometimes it's also useful to completely switch between different build files by adding some lines of code to the file settings.gradle. This solution reads the environment variable BUILD_PROFILE and inserts it into the buildFileName:

# File: settings.gradle
println "> Processing settings.gradle"
def buildProfile = System.getenv("BUILD_PROFILE")
if(buildProfile != null) {
    println "> Build profile: $buildProfile"
    rootProject.buildFileName = "build-${buildProfile}.gradle"
}
println "> Build file: $rootProject.buildFileName"

Then you run gradle like this, e.g. to use build-local.gradle:

$ BUILD_PROFILE="local" gradle compileJava
> Processing settings.gradle
> Build profile: local
> Build file: build-local.gradle

BUILD SUCCESSFUL in 3s

This approach also works for CI/CD pipelines where you might want to add extra tasks like checking quality gates or other time consuming things you don't want to execute locally.