Andrey Hihlovskiy

Professional blog on groovy, gradle, Java, Javascript and other stuff.

Killer feature in Gretty version 0.0.18 – multiple web-apps support

Let’s assume, you are developing web-applications with JVM-based languages and technologies and are looking for the solution of the following problem:

You have a bunch of web-apps, that must run all at the same time, because they call each other. You also want to debug multiple web-apps and even run integration tests – on the complete bunch.

Here is the solution to this problem: use Gretty. This is gradle plugin, capable of exactly this: running multiple web-apps, debugging, integration tests. Of course, it is open-source and available at jcenter and maven central.

Gretty can start arbitrary number of web-apps of various types: gradle projects, WAR-files in the file system and even WAR-files from maven dependencies.
Multiple web-apps feature works out-of-the-box in configureless mode, although it is fully configurable/customizable.

The central concept of Multiple web-apps feature is farm – a collection of web-apps, that should run together.

There are two ways to define and use farms:

  • Default farm is automatically created for you by Gretty. You may add artbitrary web-apps to it and then invoke farm-specific tasks: farmRun, farmRunDebug, etc. Note that farm-specific tasks are not using gretty tasks (jettyRun, jettyRunDebug, etc.), but they understand and use gretty configurations.
  • Named farms, which you create yourself in gradle script. You can add as many named farms as you want, and you can add web-apps to farms in arbitrary constellations. Each named farm provides a specific set of farm tasks. For example, if you define farm with name “XYZ”, there will be new tasks farmRunXYZ, farmRunDebugXYZ, etc. available.

You can start using multiple web-apps support right away, using the following scenario as a starting point:

Create three empty folders: ProjectA, ProjectB and ProjectC, so that folder tree looks like this:

|-- ProjectB
\-- ProjectC

Create file “ProjectA/settings.gradle”, insert code:

include 'ProjectA', 'ProjectB'

Explanation: we organize multi-project setup, so that multiple web-apps can be started/stopped by gretty-farm plugin.

Create file “ProjectA/build.gradle”, insert code:

buildscript {
  repositories {

  dependencies {
    classpath 'org.akhikhl.gretty:gretty-plugin:+'

apply plugin: 'gretty-farm'

Create file “ProjectA/ProjectB/build.gradle”, insert code:

apply plugin: 'gretty'

Create file “ProjectA/ProjectC/build.gradle”, insert code:

apply plugin: 'gretty'

Done! Now you can run multiple web-apps by running the following command in ProjectA:

gradle farmRun

Expected output:

Jetty server 9.1.0.v20131115 started.
:ProjectB runs at the address http://localhost:8080/ProjectB
:ProjectC runs at the address http://localhost:8080/ProjectC
servicePort: 9900, statusPort: 9901
Press any key to stop the jetty server.

Of course, you’ll get 404 in the browser, because web-apps don’t contain any pages. But, as soon as you add pages or/and servlets to the web-apps, things will get real.

By default farm automatically adds all subprojects of the farm project, which are facilitated with gretty plugin, to web-apps list. You can also explicitly add web-apps to the given farm.

Gretty-farm plugin defines new, distinct set of tasks for running farms: farmRun, farmRunDebug, farmRunWar, farmRunWarDebug, etc.


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