Gradle Simple Multimodule Project

A simple gradle based node multimodule project. The "app" module is a simple node express web app, and the "weather-service" module has a dependency that gets the weather for a specified weather station. When executed, the app displays the weather at localhost:4001.

The purpose was to demonstrate how to arrange node dependency relationships into a UOD, or Unit of Deployment. The UDO is a zip file that when expaneded, contains the multiple node projects and their dependencies in a zipped up build folder.

build
└── distribution
    └── gradle-multimodule.zip

When expanded, gradle-multimodule.zip has the code plus the dependencies.

.
├── app
│   ├── node_modules
│   ├── package-lock.json
│   ├── package.json
│   └── src
└── weather-service
    ├── node_modules
    ├── package-lock.json
    ├── package.json
    └── src

Usage

Requirements

Node 12 with npx 10
Gradle 5.6.4 (as of 1/2020, don't use 6+ because of AWS Lambda issues)

Install

git clone https://github.com/geocolumbus/gradle-multimodule.git
cd gradle-multimodule

Build

./gradlew clean build

Run Locally

./run-local.sh

How This Was Constructed

Lay out the project

Build the scaffolding of the project

mkdir gradle-multimodule
cd gradle-mm
gradle init
mkdir app weather-service
cd app ; gradle init
cd ..
cd weather-service ; gradle init
# Choose basic, groovy and default name
cd ..
npx express-generator --view=pug --force app
cd app
mkdir src ;  mv app.js src ; mv bin src ; mv public src ; mv routes src
cd ..
cd weather-service
npm init --force
mkdir src ; touch src/index.js
cd ..

Remove unneeded files/folders from the app and weather-service folders. Gradle runs from the root.

cd app ; rm -rf .gitignore gradlew.bat gradlew gradle ; cd ..

cd weather-service ; rm -rf .gitignore gradlew.bat gradlew gradle ; cd ..
Add dummy package-lock.json files to each node project. This is due to a bug in gradle-node-plugin that prevents local dependencies being added.

touch app/package-lock.json ; touch weather-service/package-lock.json

Add the node modules to settings.gradle (IntelliJ should identify them as modules).

rootProject.name = 'gradle-multimodule'
include 'app'
include 'weather-service'

Set up the app

Add a PORT environment setting to the main app project's start configuration so it runs on :4001.

Edit app/package.json so it looks like this.

{
  "name": "app",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "PORT=4001 node ./src/bin/www"
  },
  "dependencies": {
    "cookie-parser": "~1.4.4",
    "debug": "~2.6.9",
    "express": "~4.16.1",
    "http-errors": "~1.6.3",
    "morgan": "~1.9.1",
    "pug": "2.0.0-beta11"
  }
}

Set up the weather-service

Add this to the weather-service/src/index.js

const axios = require("axios")

const _getWeather = async function (weatherStation) {
    weatherStation = weatherStation ? weatherStation : "KOSU"
    let result = ""
    const weatherResponse = await axios.get(`https://w1.weather.gov/xml/current_obs/${weatherStation}.xml`)
    try {
        let location = (weatherResponse.data.match(/\<location\>(.*)\<\/location\>/))[1]
        let temperature = (weatherResponse.data.match(/\<temperature_string\>(.*)\<\/temperature_string\>/))[1]
        result += weatherStation + " - " + location + " - " + temperature
    } catch (e) {
        result += e
    }
    return result
}

exports.getWeather = _getWeather

Configure the gradle build

Sub project gradle.build files

Add the gradle-node-plugin to the settings.gradle file of each node project.

See: https://github.com/srs/gradle-node-plugin/blob/master/docs/installing.md

plugins {
    id "com.moowork.node" version "1.3.1"
}

node {
    version = '12.14.1'
    npmVersion = '6.13.6'
    distBaseUrl = 'https://nodejs.org/dist'
    download = true
    workDir = file("${project.buildDir}/nodejs")
    npmWorkDir = file("${project.buildDir}/npm")
    nodeModulesDir = file("${project.projectDir}")
}

// A bug with the package lock system causes npm not to download
// local dependencies.
npmInstall.args = ['--no-package-lock']

Now add code to build the distribution to each node module.

task buildDistribution(type: Copy) {
    from(project.projectDir) {
        exclude "build", "build.gradle", ".gradle", "settings.gradle"
    }
    into "${project.buildDir}/distribution/${project.name}"
}
  
buildDistribution.dependsOn npmInstall
build.dependsOn buildDistribution

Root project gradle.build

Configure the root gradle.build to work with IntelliJ, install the default tasks (base) and add a custom task that removes the node_modules from the subprojects when a clean task is executed.

apply plugin: "idea"

allprojects {
    apply plugin: "base"
}

task deleteNodeModules(type: Delete) {
    delete "app/node_modules", "weather-service/node_modules"
}

clean.dependsOn deleteNodeModules

Install code to build the UOD (Unit of Deployment) in the root gradle.build file.

task buildUOD(type: Zip, dependsOn: subprojects.build) {
    println "UOD: \"${rootProject.name}.zip\" contains project(s): " + subprojects.name
    subprojects {
        from("${it.buildDir}/distribution/") {
            include '**/**'
        }
    }
    archiveFileName = "${rootProject.name}.zip"
    destinationDirectory = file('./build/distribution')
}

build.dependsOn buildUOD

geocolumbus/gradle-multimodule