Multidomain Seed [Play 2.4 - Scala]
Note: All this information is also available as a tutorial if you run the app using Activator UI.
Let's suppose you want to develop a whole project which has two different services: the typical public webpage and the private admin one. You also want a specific subdomain for the admin webpage, so we will have:
admin.myweb.com: private administration webpage.www.myweb.comormyweb.com: public webpage.
And let's also suppose you prefer to have these services isolated in your production server. So you would be able to manage them separately (with different PIDs, different ports, different resources…).
Then, we have the following objectives:
- Development should be simple.
activator runshould be enough to run all services at the same time. - Common code, dependencies and modules should be easily shared.
- We should be able to compile, test and run each service separately in development and production.
- We should distribute each service separately.
- It should be a template ready to use with the following features:
- It shoud explain:
- How to share every common code to avoid duplications (models, controllers, views, CoffeeScript, LESS, ...).
- How to use it for development, test and production.
Multiproject
This template has 3 subprojects:
web: will contain all the specific code for the public webpage service.admin: will contain all the specific code for the private administration webpage service.common: will contain all the common code shared between the other subprojects.
Obviously, this is a template, so you can easily change its names or add more modules. Once you understand how it works you will find it easy to modify.
This is the basic structure of the whole project:
play-multidomain-seed
└ build.sbt
└ app
└ RequestHandler.scala
└ conf
└ root-dev.conf
└ routes
└ project
└ build.properties
└ plugins.sbt
└ Common.scala
└ modules
└ admin
└ build.sbt
└ app
└ ErrorHandler.scala
└ assets
└ javascripts
└ main-admin.coffee
└ admin.coffee
└ admin
└ otherLib.coffee
└ stylesheets
└ main.less
└ controllers
└ Application.scala
└ Assets.scala
└ models
└ Models.scala
└ views
└ admin
└ index.scala.html
└ main.scala.html
└ conf
└ admin-dev.conf
└ admin-prod.conf
└ admin.routes
└ public
└ images
└ test
└ web
└ ...
└ common
└ ...
Let's try to explain briefly how it is configured. For running the whole project we have the following configuration files:
build.sbt: configures root project and declares every subproject.conf/root-dev.conf(used when whole project is running): the default one. In the next section it is explained in detail.conf/routes(used when whole project is running): routes file for the whole project. It simply imports the routes file of every subproject.app/RequestHandler.scala(used when whole project is running): the RequestHandler object for the whole project. It determines the subdomain for each request (admin or web) and delegates its behaviour to the corresponding subproject.
And for running each subproject independently:
modules/[subproject]/build.sbt: configures the [subproject].modules/[subproject]/conf/[subproject]-dev.conf(used when only this subproject is running): the default one, it declares the routes file for the subproject while running or testing only this subproject.modules/[subproject]/conf/[subproject]-prod.conf(used when only this subproject is running): it declares the routes file for the subproject while distributing only this subproject.modules/[subproject]/conf/[subproject].routes(used when only this subproject is running): routes file for this subproject.modules/[subproject]/app/ErrorHandler.scala(used when only this subproject is running): the ErrorHandler object for this subproject.
The common code for every build.sbt file is defined at:
project/Common.scala: contains all the shared common variables and code for sbt files.
And the rest of relevant folders and files are:
modules/[subproject]/app/assets/javascripts/: folder for CoffeeScript files of this subproject.modules/[subproject]/app/assets/stylesheets/: folder for LESS files of this subproject.modules/[subproject]/app/controllers/: folder for the controllers of this subproject.modules/[subproject]/app/controllers/Assets.scala: it is necessary to implement anobject Assets extends controllers.AssetsBuilderfor every subproject.modules/[subproject]/app/views/[subproject]/: folder for the views of this subproject.modules/[subproject]/public/: folder for every public file of this subproject.modules/[subproject]/test/: folder for every test file for this subproject.
Please check the Splitting the route file section within the documentation page about SBT Sub-projects.
Configuration files
As we want to run or test the whole project and also run, test or dist admin and web subprojects, we have several configuration files. Each one has its own particular purpose:
-
conf/root-dev.conf: the configuration file that is called by default when the whole project is running. It simply includes theshared.dev.conffile. -
conf/shared.dev.conf: declares all the development configuration shared for the whole project and every subproject. -
conf/shared.prod.conf: includes theshared.dev.conffile and overrides every configuration that is specific for production and it is shared for the whole project and every subproject. -
modules/[subproject]/conf/[subproject].conf: declares the specific configuration for this subproject for development or production. It must declare the route file for this subproject. -
modules/[subproject]/conf/[subproject]-dev.conf: the configuration file that is called by default when the [subproject] is running. It simply includes theshared.dev.confand[subproject].conffiles. -
modules/[subproject]/conf/[subproject]-prod.conf: declares the specific configuration for this subproject for production. It includes theshared.prod.confand[subproject].conffiles. -
modules/[subproject]/conf/shared.dev.conf: it is simply a copy ofconf/shared.dev.conf. It must be copied here to be available for production distribution. -
modules/[subproject]/conf/shared.prod.conf: it is simply a copy ofconf/shared.prod.conf. It must be copied here to be available for production distribution.
It has been added a key called this.file in many of the configuration files and it is shown in the index web page when you run it. Please, play with it to see how it is overridden by each configuration file depending the project and mode (dev or prod) you are running.
The corresponding configuration file is correctly taken for each case thanks to the settings lines in Common.scala:
javaOptions += s"-Dconfig.resource=$module-dev.conf"
Tip: as files shared.dev.conf and shared.prod.conf for every subproject are the same as the general ones, you can use aliases or symbolic links for them in order to avoid to maintain all of them.
Assets: RequireJS, Digest, Etag, Gzip, Fingerprint
To configure all of these features, for each service (web and admin) we have the following:
pipelineStages := Seq(rjs, digest, gzip)
RjsKeys.mainModule := s"main-$module"
The first line declares the asset pipeline. The second one establishes the corresponding RequireJS main config file to each module.
Then you can put the common RequireJS modules in the subproject common, within the folder modules/common/app/assets/javascripts/common/. And the specific code for each subproject will be added within its corresponding folder modules/[subproject]/app/assets/javascripts/. Take care with possible namespace problems while running the whole project. In the example, the subproject admin has other RJS module within subfolder admin.
The common Assets are packaged as Webjars for the other subprojects that depend on it, so you must indicate the corresponding RequireJS path to the common lib in the RJS config file as:
require.config
paths:
common: "../lib/common/javascripts"
jquery: "../lib/jquery/jquery"
...
Now we just simply need to declare the RequireJS as:
<script data-main="@routes.Assets.versioned("javascripts/main-web.js")" src="@routes.Assets.versioned("lib/requirejs/require.js")" type="text/javascript"></script>
For more information, go to the documentation page about Assets, the tutorial play-2.3-highlights in Activator UI, or the website of RequireJS.
Custom AssetsBuilder
In order to avoid code like this:
href="@routes.Assets.versioned("images/favicon.png")"
href="@routes.Assets.versioned("stylesheets/main.css")">
data-main="@routes.Assets.versioned("javascripts/main-web.js")"
src="@routes.Assets.versioned("lib/requirejs/require.js")"
src="@routes.Assets.versioned("lib/common/images/logo.png")"
because it can be very tedious to remember the specific path for every resource depending of its type or if it's from the common subproject or not, I prefer using this syntax:
href="@routes.Assets.img("favicon.png")"
href="@routes.Assets.css("main.css")">
data-main="@routes.Assets.js("main-web.js")"
src="@routes.Assets.lib("requirejs/require.js")"
src="@routes.Assets.commonImg("logo.png")"
To get that we only need to define a custom AssetsBuilder class (you can see it in modules/common/app/controllers/Assets.scala).
package controllers.common
class Assets extends AssetsBuilder(DefaultHttpErrorHandler) {
def public (path: String, file: Asset) = versioned(path, file)
def lib (path: String, file: Asset) = versioned(path, file)
def css (path: String, file: Asset) = versioned(path, file)
def commonCss (path: String, file: Asset) = versioned(path, file)
def js (path: String, file: Asset) = versioned(path, file)
def commonJs (path: String, file: Asset) = versioned(path, file)
def img (path: String, file: Asset) = versioned(path, file)
def commonImg (path: String, file: Asset) = versioned(path, file)
}
Add a simple Assets class within the controllers folder of each subproject:
package controllers.web
class Assets extends controllers.common.Assets
And add the following in the routes files:
GET /public/*file controllers.web.Assets.public(path="/public", file: Asset)
GET /lib/*file controllers.web.Assets.lib(path="/public/lib", file: Asset)
GET /css/*file controllers.web.Assets.css(path="/public/stylesheets", file: Asset)
GET /js/*file controllers.web.Assets.js(path="/public/javascripts", file: Asset)
GET /img/*file controllers.web.Assets.img(path="/public/images", file: Asset)
GET /common/css/*file controllers.web.Assets.commonCss(path="/public/lib/common/stylesheets", file: Asset)
GET /common/js/*file controllers.web.Assets.commonJs(path="/public/lib/common/javascripts", file: Asset)
GET /common/img/*file controllers.web.Assets.commonImg(path="/public/lib/common/images", file: Asset)
Public files
You can put the common public files in the subproject common, within the folder modules/common/public/. The common Assets are packaged as Webjars for the other subprojects that depend on it, so you must access to them through their correspoding lib folder:
<img src="@routes.Assets.commonImg("play.svg")"></img>
And the specific code for each subproject will be added within its corresponding folder modules/[subproject]/public/.
Shared resources
If you have shared resources between your subprojects, like for example uploaded images from your users, you need to render or download them from a shared folder. Note you can't consider a shared resource like a asset.
The process is very similar than the custom AssetsBuilder:
package controllers.common
class SharedResources extends Controller {
private lazy val rscFolder = play.api.Play.current.configuration.getString("rsc.folder").get
private def rscPath (uri: String) = rscFolder + uri
def rsc (file: String) = Action(Ok.sendFile(new File(rscPath(file))))
}
Add a simple SharedResources class within the controllers folder of each subproject:
package controllers.web
class SharedResources extends controllers.common.SharedResources
And add the following in the routes files:
GET /rsc/*file controllers.web.SharedResources.rsc(file: String)
RequestHandler
We need a global RequestHandler to run the whole project and get to things:
- Determine the subdomain for each request (
adminorweb) and delegate its behaviour to the corresponding subproject. - Rewrite the urls for the
css,jsandimgassets for the corresponding subproject. This is because for the root project these resources are located atpublic/lib/[subproject]/.
These things are done overriding the routeRequest method of the RequestHandler.
Webjars
The common Webjars are included within the field Common.commonDependencies in the file project/Common.scala. In our case:
val commonDependencies = Seq(
...
"org.webjars" % "jquery" % "2.1.4",
"org.webjars" % "bootstrap" % "3.3.5",
"org.webjars" % "requirejs" % "2.1.19"
...
)
And the specific webjars for a subproject are declared in the file modules/[subproject]/build.sbt. For example, for the web subproject:
libraryDependencies ++= Common.commonDependencies ++: Seq(
"org.webjars" % "bootswatch-cerulean" % "3.3.4+1"
)
Then, to access to their resources simply remember they are inside lib folder. For the previous examples:
<link rel="stylesheet" media="screen" href="@routes.Assets.lib("bootswatch-cerulean/css/bootstrap.min.css")">
<script src="@routes.Assets.lib("jquery/jquery.min.js")"></script>
<script src="@routes.Assets.lib("bootstrap/js/bootstrap.min.js")"></script>
If you have doubts about the specific route of any webjar resource, remember it is directly downloaded within the relative folder target/web/web-modules/main/webjars/lib. So you can easily check the file structure that has been downloaded by the webjar.
CoffeeScript
The corresponding plugin needs to be active in file project/plugins.sbt.
The common CoffeeScript files are in the subproject common, within the folder modules/common/app/assets/javascripts. And the specific code for each subproject will be added within its corresponding folder modules/[subproject]/app/assets/javascripts/.
To access to the compiled file you simply have to reference to its JS equivalent:
<script src="@routes.Assets.js("main.js")"></script>
For more information, go to the documentation page about CoffeeScript.
LESS
The corresponding plugin needs to be active in file project/plugins.sbt. And the next configuration has been added to every subproject to be able to work with partial LESS source files (in project/Common.scala):
includeFilter in (Assets, LessKeys.less) := "*.less"
excludeFilter in (Assets, LessKeys.less) := "_*.less"
With that, every LESS file not prepended by an underscore (_) will be compiled, and they could import the code from the LESS files prepended by an underscore.
The common LESS files are in the subproject common, within the folder modules/common/app/assets/stylesheets/. And the specific code for each subproject will be added within its corresponding folder modules/[subproject]/app/assets/stylesheets/.
To import a common LESS file, import it directly as (you can check an example in modules/admin/app/assets/stylesheets/_variables.less):
@import "../../../../../common/app/assets/stylesheets/_common.less";
To access to the compiled file you simply have to reference to its CSS equivalent:
<link rel="stylesheet" media="screen" href="@routes.Assets.css("main.css")">
For more information, go to the documentation page about LESS.
Development
First of all, to get access to admin subdomain you will need modify your /etc/hosts files (or the equivalent in your S.O.) to map the next URLs to localhost or (127.0.0.1). For example, add the following lines:
127.0.0.1 myweb.com
127.0.0.1 www.myweb.com
127.0.0.1 admin.myweb.com
Then, simply execute:
$ activator run
or
[play-multidomain-seed] $ run
And that's all! The whole project will run using the conf/root-dev.conf file enabling all the services at once. You can go with your browser and check the URLs:
myweb.com:9000orwww.myweb.com:9000: public webpageadmin.myweb.com:9000: private admin webpage
As you can see, you must add the default 9000 port, but you can use the port you want with the parameter with activator run -Dhttp.port=9001.
If you want to run only one subproject separately, you have to get into the subproject and run:
[play-multidomain-seed] $ project admin
[admin] $ run
Test
Each subproject has its own test files within the folder modules/[subproject]/test.
To run the tests for every subproject at once, simply execute:
[play-multidomain-seed] $ test
And for a unique subproject, get into it and test it:
[play-multidomain-seed] $ project admin
[admin] $ test
Production
Simply execute:
$ activator dist
or
[play-multidomain-seed] $ dist
Now you have a zip file for each module.
/play-multidomain-seed/modules/web/target/universal/web-1.0-SNAPSHOT.zip
/play-multidomain-seed/modules/admin/target/universal/admin-1.0-SNAPSHOT.zip
So you can extract wherever you want and execute them separately. For example with:
./admin-1.0-SNAPSHOT/bin/admin -Dconfig.resource=admin-prod.conf -Dhttp.port=9001 -Dapplication.secret=abcdefghijk &
Note it is added the & at the end to run the app in the background. The PID will be stored in RUNNING_PID file, so when you want to stop the app, just execute:
kill $(cat path/to/RUNNING_PID)
If you would like to test the whole project in production mode, you should be able to execute the start command as:
[play-multidomain-seed] $ start
Please, check the documentation about Production Configuration for more parameters. And also check about Application Secret.
Thanks to
http://www.playframework.com/documentation/2.4.x/SBTSubProjects
http://eng.kifi.com/multi-project-deployment-in-play-framework/ -> https://github.com/kifi/multiproject
http://parleys.com/play/527f7a92e4b084eb60ac7732/chapter17/about
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