NY Java SIG

prerequisites.md

1. Install Eclipse 3.7 or newer
2. Signup for a Heroku account
3. Install the Heroku Eclipse Plugin (Complete the steps up to "Create app from template")

session.md

Heroku Basics

Heroku is a Cloud Application Platform

• Supports Java, Scala, Python, Node.js, Ruby, etc
• Instant Deployment via Git or WAR files
• Instant Scalability
• Managed Infrastructure: Servers, Load Balancers, Databases, etc
• Extended via Add-ons: http://addons.heroku.com

Heroku Basics

Deployment

1. Copy git repo to Heroku:

    git push heroku master
   

2. Heroku compiles code

3. Heroku creates a "slug" file

4. Heroku deploys "slug" onto a "dyno"

5. Heroku starts the process

Terminology

http://heroku.com/how

User has 0 or more Applications

Application has 1 git repository

Application has 0 or more Processes

Process is defined in a Procfile

Process named "web" can listen on one port for HTTP

Process runs on 0 or more Dynos

Dynos are isolated (LXC) and managed execution environments

Application has 0 more more external resources - Heroku Add-ons

Buildpack receives a git push and produces a "slug"

Slug contains the non-system dependencies for all Processes

Dynos are ephemeral and stateless

HTTP(s) requests are randomly routed to the "web" Dynos

Pricing

http://www.heroku.com/pricing

$0.05 / dyno hour

750 free dyno hours per application per month

Deploy An App

1. In Eclipse select File > New > Other...
2. Expand the Heroku section, select Create Heroku App from Template, select Next
3. Select Spring MVC & Tomcat application, select Finish

Open the App

1. In Eclipse select Window > Show View > Other...
2. Expand the Heroku section, select My Heroku Applications, select Ok
3. Locate the newly created application in My Heroku Applications
4. Right-click on the application and select Open

Run the App Locally

1. In Eclipse select Run > Run Configurations...
2. Double-click on Java Application
3. Set the name to something like arcane-taiga-7336 webapp-runner (using the application's name)
4. Set the Main class to webapp.runner.launch.Main
5. In the Arguments tab add src/main/webapp as a Program argument
6. Select Run
7. Visit http://localhost:8080

About the App

• BYOC via pom.xml
• Define processes via the Procfile
• Database configured via the DATABASE_URL environment variable

Deploy Changes

1. Make a change to the application and test locally
2. In Eclipse right-click on the project name in the Project Explorer
3. Select Team > Commit...
4. Enter a Commit message
5. Select Commit
6. Right-click on the project name in the Project Explorer
7. Select Team > Push to Upstream
8. View the application on Heroku in your browser

View Logs

1. In Eclipse select the My Heroku Applications tab
2. Right-click on the application and select View logs

Scale the App

This requires a verified account on Heroku: http://heroku.com/verify

1. In Eclipse select the My Heroku Applications tab
2. Right-click on the application and select Scale
3. Enter the number of Dynos to scale the web process to
4. Select Ok