6 Application Profiles

grails create-app myapp

You can specify a different profile with the profile argument:

grails create-app myapp --profile=rest-api

Profiles encapsulate the project commands, templates and plugins that are designed to work for a given profile. The source for the profiles can be found on Github, whilst the profiles themselves are published as JAR files to the Grails central repository.

To find out what profiles are available use the list-profiles command:

$ grails list-profiles

For more information on a particular profile use the profile-info command:

$ grails profile-info rest-api

Profile Repositories

By default Grails will resolve profiles from the Grails central repository. However, you can define additional profile repositories in the USER_HOME/grails/settings.groovy file:

grails {
  profiles {
    repositories {
      myRepo {
        url = "http://foo.com/repo"
        snapshotsEnabled = true
      }
    }
  }
}

Note that Grails uses Aether to resolve profiles, as a Gradle instance is not yet available when the create-app command is executed. This means that you can also define repositories and more advanced configuration (proxies, authentication etc.) in your USER_HOME/.m2/settings.xml file if you wish.

6.1 Creating Profiles

To create a new profile you can use the create-profile command which will create a new empty profile that extends the base profile:

$ grails create-profile mycompany

The above command will create a new profile in the "mycompany" directory where the command is executed. If you start interactive mode within the directory you will get a set of commands for creating profiles:

$ cd mycompany
$ grails
| Enter a command name to run. Use TAB for completion:
grails>
create-command      create-creator-command      create-feature      create-generator-command    create-gradle-command   create-template

The commands are as follows:

• create-command - creates a new command that will be available from the Grails CLI when the profile is used
• create-creator-command - creates a command available to the CLI that renders a template (Example: create-controller)
• create-generator-command - creates a command available to the CLI that renders a template based on a domain class (Example: generate-controller)
• create-feature - creates a feature that can be used with this profile
• create-gradle-command - creates a CLI command that can invoke gradle
• create-template - creates a template that can be rendered by a command

To customize the dependencies for your profile you can specify additional dependencies in profile.yml.

Below is an example profile.yml file:

features:
    defaults: 
        - hibernate
        - asset-pipeline
build:
    plugins:
        - org.grails.grails-web
    excludes:
        - org.grails.grails-core
dependencies:
    compile:
        - "org.mycompany:myplugin:1.0.1"

With the above configuration in place you can publish the profile to your local repository with gradle install:

$ gradle install

Your profile is now usable with the create-app command:

$ grails create-app myapp --profile mycompany

With the above command the application will be created with the "mycompany" profile which includes an additinal dependency on the "myplugin" plugin and also includes the "hibernate" and "asset-pipeline" features (more on features later).

Note that if you customize the dependency coordinates of the profile (group, version etc.) then you may need to use the fully qualified coordinates to create an application:

$ grails create-app myapp --profile com.mycompany:mycompany:1.0.1

6.2 Profile Inheritance

dependencies {
    runtime project(':base')
}

By inheriting from a parent profile you get the following benefits:

• When the create-app command is executed the parent profile's skeleton is copied first
• Dependencies and build.gradle is merged from the parent(s)
• The application.yml file is merged from the parent(s)
• CLI commands from the parent profile are inherited
• Features from the parent profile are inherited

To define the order of inheritance ensure that your dependencies are declared in the correct order. For example:

dependencies {
    runtime project(':plugin')
    runtime project(':web')
}

In the above snippet the skeleton from the "plugin" profile is copied first, followed by the "web" profile. In addition, the "web" profile overrides commands from the "plugin" profile, whilst if the dependency order was reversed the "plugin" profile would override the "web" profile.

6.3 Publishing Profiles

Publishing Profiles to the Grails Central Repository

Any profile created with the create-profile command already comes configured with a grails-profile-publish plugin defined in build.gradle:

apply plugin: "org.grails.grails-profile-publish"

To publish a profile using this plugin to the Grails central repository first upload the source to Github (closed source profiles will not be accepted). Then register for an account on Bintray and configure your keys as follows in the profile's build.gradle file:

grailsPublish {
  user = 'YOUR USERNAME'
  key = 'YOUR KEY'
  githubSlug = 'your-repo/your-profile'
  license = 'Apache-2.0'
}

The githubSlug argument should point to the path to your Github repository. For example if your repository is located at https://github.com/foo/bar then your githubSlug is foo/bar

With this in place you can run gradle publishProfile to publish your profile:

$ gradle publishProfile

The profile will be uploaded to Bintray. You can then go the the Grails profiles repository and request to have your profile included by clicking "Include My Package" button on Bintray's interface (you must be logged in to see this).

Publishing Profiles to an Internal Repository

The aforementioned grails-profile-publish plugin configures Gradle's Maven Publish plugin. In order to publish to an internal repository all you need to do is define the repository in build.gradle. For example:

publishing {
    repositories {
        maven {
            credentials {
                username "foo"
                password "bar"
            }
            url "http://foo.com/repo"
        }
    }  
}

Once configured you can publish your plugin with gradle publish:

$ gradle publish

6.4 Understanding Profiles

web
    * commands
        * create-controller.yml
        * run-app.groovy    
        …
    * features
        * asset-pipeline
            * skeleton
            * feature.yml
    * skeleton
        * grails-app
            * controllers
            …
        * build.gradle
    * templates
        * artifacts
            * Controller.groovy
    * profile.yml

The above example is a snippet of structure of the 'web' profile. The profile.yml file is used to describe the profile and control how a the build is configured.

Understanding the profile.yml descriptor

The profile.yml can contain the following child elements.

1) repositories

A list of Maven repositories to include in the generated build. Example:

repositories:
    - "https://repo.grails.org/grails/core"

2) build.repositories

A list of Maven repositories to include in the buildscript section of the generated build. Example:

build:
    repositories:
        - "https://repo.grails.org/grails/core"

3) build.plugins

A list of Gradle plugins to configure in the generated build. Example:

build:
    plugins:
        - eclipse
        - idea
        - org.grails.grails-core

4) build.excludes

A list of Gradle plugins to exclude from being inherited from the parent profile:

build:
    excludes:
        - org.grails.grails-core

5) dependencies

A map of scopes and dependencies to configure. The excludes scope can be used to exclude from the parent profile. Example:

dependencies:
    excludes:
        - "org.grails:hibernate"
    build:
        - "org.grails:grails-gradle-plugin:$grailsVersion" 
    compile:
        - "org.springframework.boot:spring-boot-starter-logging"
        - "org.springframework.boot:spring-boot-autoconfigure"

6) features.defaults

A default list of features to use if no explicit features are specified.

features:
    defaults: 
        - hibernate
        - asset-pipeline

What happens when a profile is used?

When the create-app command runs it takes the skeleton of the parent profiles and copies the skeletons into a new project structure.

The build.gradle file is generated as is result of obtaining all of the dependency information defined in the profile.yml files and produces the required dependencies.

The command will also merge any build.gradle files defined within a profile and its parent profiles.

The grails-app/conf/application.yml file is also merged into a a single YAML file taking into account the profile and all of the parent profiles.

6.5 Creating Profile Commands

description: 
    - Creates a controller
    - usage: 'create-controller [controller name]'
    - completer: org.grails.cli.interactive.completers.DomainClassCompleter
    - argument: "Controller Name"
      description: "The name of the controller"     
steps:
 - command: render
   template: templates/artifacts/Controller.groovy
   destination: grails-app/controllers/artifact.package.path/artifact.nameController.groovy
 - command: render
   template: templates/testing/Controller.groovy
   destination: src/test/groovy/artifact.package.path/artifact.nameControllerSpec.groovy
 - command: mkdir
   location: grails-app/views/artifact.propertyName

Commands defined in YAML must define one or many steps. Each step is a command in itself. The available step types are:

• render - To render a template to a given destination (as seen in the previous example)
• mkdir - To make a directory specified by the location parameter
• execute - To execute a command specified by the class parameter. Must be a class that implements the Command interface.
• gradle - To execute one or many Gradle tasks specified by the tasks parameter.

For example to invoke a Gradle task, you can define the following YAML:

description: Creates a WAR file for deployment to a container (like Tomcat)
minArguments: 0
usage: |
 war
steps:
 - command: gradle
   tasks:
     - war

If you need more flexiblity than what the declarative YAML approach provides you can create Groovy script commands. Each Command script is extends from the GroovyScriptCommmand class and hence has all of the methods of that class available to it.

The following is an example of the create-script command written in Groovy:

description( "Creates a Grails script" ) {
  usage "grails create-script [SCRIPT NAME]"
  argument name:'Script Name', description:"The name of the script to create"
  flag name:'force', description:"Whether to overwrite existing files"
}
def scriptName = args[0]
def model = model(scriptName)
def overwrite = flag('force') ? true : false
render  template: template('artifacts/Script.groovy'), 
        destination: file("src/main/scripts/${model.lowerCaseName}.groovy"),
        model: model,
        overwrite: overwrite

For more information on creating CLI commands see the section on Creating custom scripts in the Command Line section of the user guide.

6.6 Creating Profile Features

To create a feature use the create-feature command from the root directory of your profile:

$ grails create-feature myfeature

This will create a myfeature/feature.yml file that looks like the following:

description: Description of the feature
# customize versions here
# dependencies:
#   compile:
#     - "org.grails.plugins:myplugin2:1.0"
#

As a more concrete example. The following is the feature.yml file from the "asset-pipeline" feature:

description: Adds Asset Pipeline to a Grails project
build:
    plugins:
        - asset-pipeline
dependencies:
    build:
        - 'com.bertramlabs.plugins:asset-pipeline-gradle:2.5.0'
    runtime:
        - "org.grails.plugins:asset-pipeline"

The structure of a feature is as follows:

FEATURE_DIR
    * feature.yml
    * skeleton
        * grails-app
            * conf
                * application.yml
        * build.gradle

The contents of the skeleton get copied into the application tree, whilst the application.yml and build.gradle get merged with their respective counterparts in the profile by used.

With the feature.yml you can define additional dependencies. This allows users to create applications with optional features. For example:

$ grails create-app myapp --profile myprofile --features myfeature,hibernate

The above example will create a new application using your new feature and the "hibernate" feature.