Inside Grails: The Build System& Plugin Management

byPeter Ledbrook

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Shell scripts

startGrails launches VM

Adds groovy-all & grails-bootstrap to system classpath

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Create GrailsRootLoader

Load classpath from groovy-starter.conf

Load GrailsScriptRunner in GRL and execute

Class loader isolation

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Create BuildSettings if it doesn't exist

Populate root loader

Initialise Gant

Pre-populate Gant binding

Interactive mode

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Parse & run Grails scripts

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Load Grails using given class loader

Isolate Grails from parent class loader

Starting The Grails Build System

grails grails­debug

startGrails

GrailsStarter

GrailsScriptRunner

Gant

Ant task Maven plugin

GrailsBuildHelper

BuildSettings

Project structure

BuildConfig.groovy & settings.groovy

Dependencies

Class loader hell?

System loader

GrailsRootLoader

URLClassLoader

System loader

GrailsClassLoader

“rootLoader”

“classLoader”

grailsApp.classLoader

Script cacheResourcesJARs (application & plugins)

Script cacheClasses

Artifacts (*.groovy)

Context Class Loader

Starts as root loader (GrailsStarter)

Becomes ”classLoader” (GrailsScriptRunner)

”classes” directory

Ends as Grails application class loader (DefaultGrailsApplication)

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

General settings

Create PluginBuildSettings

Configure environment

getPropertyValue()

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Set up common/compile/test/runtime classpaths

Target classpath

grails.*.classpath Ant paths

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Install Ant build listener

Load event scripts (_Events.groovy)

Add event() method

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Grails app without servlet container

Create application context, with

GrailsApplication

GrailsPluginManager

Used by integration tests, generate scripts, and others

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Grails app with servlet container

Should use runtime classpath

Plugin change scanner

Grails Scripts

_GrailsSettings _GrailsClasspath _GrailsEvents

_GrailsBootstrap _GrailsRun _GrailsWar

Common

End use

Create WAR

Package runtime dependencies

Plugins

Build

Manage plugin installations

Plugin dependencies

Scripts

Lib dependencies

Repositories

Runtime

Load plugins

Add Spring beans

Add dynamic methods

Web descriptor

Plugins in the Build

Scripts

_PluginDependencies _GrailsPlugins _GrailsPluginDev

Classes

PluginBuildSettings PluginInfoGrailsPluginUtils

Files

plugin.xml dependencies.groovy

Plugins at Runtime

*GrailsPlugin

GrailsPluginManager

AbstractGrailsPluginManager

DefaultGrailsPluginManager

GrailsPlugin

AbstractGrailsPlugin

DefaultGrailsPlugin

*GrailsPlugin*GrailsPluginPlugin  descriptors

Overlap

_PluginDependencies: target ”loadPlugins”

Called by bootstrap, package app

Required to generate web.xml

Creates temporary GrailsApplication and GrailsPluginManager instances

Plugins may be loaded twice or more!