Objectives

Deploy a Play Application to the cloud

Setup.

We need 2 free services to get our Play Application live in the Cloud. In this step we create the necessary accounts.

Heroku
Dropbox

(1) Heroku

Visit this site:

https://www.heroku.com

And sign up for a new account.

Once confirmed, log in and go you your Dashboard:

https://dashboard.heroku.com/apps

This is a Platform as a Service provided (PaaS), you can read about PaaS here:

https://en.wikipedia.org/wiki/Platform_as_a_service

We will be using this service to get our Play Applications Live.

(2) Dropbox

If you do not already have one, create and account here:

https://www.dropbox.com/

You will then need to download the Dropbox Application, which will be a native application installed on your computer:

https://www.dropbox.com/install

When this is installed, a folder called Dropbox will be created on your workstation - which will also be mirrored in the cloud. Make sure you can locate this folder and that it is in fact synced with the cloud.

Preparing the Play Application for Deployment

You may have your own version of the Todolist 2 application - which you can use for the rest of this lab. Alternatively, you can download the the version we left at the end of lab 10:

https://github.com/edeleastar/todolist/releases/tag/todolist-2.end

If you download the zip above, and expand - you will have a complete Play application like this:

We need to make the set the following parameters to prepare it for deployment:

JDK Version
Play Version
Database Settings

You may want to import the project into Idea to make the changes below.

(1)JDK Version

Create a new file in the project root:

system.properties

java.runtime.version=8

This sets the JDK version our app will need when deployed.

(2) Play Version

Locate this file:

conf/dependencies.yml

# Application dependencies

require:
    - play

Change it to the following:

# Application dependencies

require:
    - play 1.5.0
    - org.postgresql -> postgresql 42.2.2:
       force: true

This determines the precise version of Play + the database drivers it should use.

(3) Database Settings

We also need to set the database connection configuration to use when deployed. Open application.conf and locate the following line:

conf/application.conf

db.default=mem

Comment out this line by placing a # in the first line:

# db.default=mem

Insert the following directly below:

db=${DATABASE_URL}
jpa.dialect=org.hibernate.dialect.PostgreSQLDialect
jpa.ddl=update

NB: This very last change will mean that YOUR APP WILL NO LONGER RUN LOCALLY! (apologies for the caps). So you will need to reverse the very last change if you want to run locally again.

Creating & Configure the Application on Heroku

Now we need to create and configure the application on Heroku:

Create App
Link to Dropbox
Configure Buildpack

(1) Create Application

Back in the Heroku

https://www.heroku.com

Select 'New` and create a new application.

Give the app a name - this will have to be unique, so perhaps consider using your initials or name in the application name:

You might also locate the app in Europe. Press Create App and an application console will be displayed:

(2) Link to Dropbox

One of the options is Dropbox ... press it and you will be asked to authorise against your Dropbox credentials.

The Control panel will now have these additional options.

Also, check your Dropbox folder on your workstation. It should have a new folder - the same name as the application you created - inside an Dropbox/Apps/Heroku folder

When we are ready to deploy our application we place a copy in here. Do this now, copy the contents of the todolist folder into the newly created folder:

It might look like this:

We now have 2 versions of our app - then one we are working on, perhaps in IDEA - and another version we have copied out to a dropbox folder.

If you are using one of your own projects, be sure to exclude a .git subdirectory (if there is one) from the copy on dropbox.

(3) Configure Buildpack

We are now almost ready to deploy. We need to do one more step. Back in Heroku, switch to the Settings panel:

Press the Add Buildpack:

In the above, we have added this url:

https://github.com/heroku/heroku-buildpack-play

Save changes and the buildpack should be installed:

The build pack is needed to inform Heroku how a play app is configured and managed.

Deploy the Application

Back in the Deploy panel - we can now press the Deploy button.

This will take a minute or so - and will log its progress...

If all goes well -- it should look like this:

This could take a minute or two...

Note the green tick indicating it is deployed. Press View and the app should be available:

You should be able to ad and remove todos. Log out, sign up a new user etc...

Logs

Back in the Heroku Console - select more on the top right:

Select View logs.

This is the equivalent of the console when you were running the app locally on your workstation. When testing the deployed application it is useful to always keep this view open. It enables you to monitor the application, identify potential errors and generally keep an eye on its operation.

You now have 2 versions of the source of your application

The version you are developing using IDEA
A copy of the application on a dropbox folder, shared with Heroku.

It is a good idea to keep these separate - and when you update the application you copy the source over to the dropbox version.

Running Locally

Please note: This change you made to conf/application.conf:

conf/application.conf

# db.default=mem

db=${DATABASE_URL}
jpa.dialect=org.hibernate.dialect.PostgreSQLDialect
jpa.ddl=update

Will prevent you from running the application locally. i.e. it will fail to launch when running via the play run command. Therefore, for the version of the application you are editing via IDEA, make suer to reverse the changes if you wish to run locally:

db.default=mem

# db=${DATABASE_URL}
# jpa.dialect=org.hibernate.dialect.PostgreSQLDialect
# jpa.ddl=update

Perhaps best to keep this file NOT in sync with the version on dropbox

Deploying Again

The procedure for updating the running app is to

Copy the relevant source into the dropbox version
Press the Deploy button again:

In the above example - it has not detected any changes, so will not deploy.

When deploying, the Build Logs become visible:

These logs are separate from the run time logs described above. You will need to monitor these logs occasionally in case any errors arise.

Database Dashboard

If you have been relying on this link:

http://locathost9000/@db

...to view the browser when running locally - this will NOT work for the deployed version.

However, Heroku supports a free add-on which fulfils a similiar role:

https://www.adminium.io/dashboard

Associating this service with your app is reasonably straightforward, and is all carried via the web interface.

It will involve installing the Addon:

This will ask for authorisation:

You will then be asked to enable it for your application - and you will eventually be able to browse its models like this:

You will even be able to edit the contents.

You will also be able to add tables to a Dashboard :

The dashboard is available at this url:

https://www.adminium.io/dashboard

There are additional Widgets you can experiment with here to monitor database activity over time.

Exercises

Exercise 1: Deploy Playlist 5

Deploy the latest playlist application:

https://github.com/edeleastar/playlist/releases/tag/playlist.5.end

You will need to follow precisely steps 02, 03 and 04 from this lab.

Exercise 2: Workspace

See if you can arrange your workspace like this:

Here we are monitoring the deploy logs, the main application logs, the database console and the application itself (including the browser tools).

Try some variation of this now and get familiar with the nature of the information in each of the windows. Proceed through a deploy cycle while doing this (make a cosmetic change to the app in dropbox to allow a deploy to be triggered)