Introduction

This is a project that demonstrates deploying a DropWizard project on Heroku. This project, through Dropwizard framework, handles a GET request to http://drift-slack-demo.herokuapp.com/weather by returning a hardcoded string. The resource class that handles this request is under src/main/java/com/example/weatherbot/resources/WeatherResource.java.

Run This Application Locally

First, cd into the directory you want to run this project in. Then, run the following commands.

• Clone the project

$ git clone https://github.com/jennakwon06/dropwizard_heroku_weatherbot.git

• Build the project

$ mvn clean install

• Run the server locally

$ java -jar target/weatherbot-1.0.1-SNAPSHOT.jar server weatherbot.yml

• Check http://localhost:8080/weather. port 8080 is specified in weatherbot.yml.

Run This Application on Heroku

You can see that this app is currently running on Heroku at http://drift-slack-demo.herokuapp.com/weather. If you would like to run your Dropwizard project on Heroku as well, you must go through the below procedures.

• Sign up for a free account if you don't have one already, and install Heroku Toolbelt.
• Log into your credentials

$   heroku login
Enter your Heroku credentials.
Email: [email protected]
Password (typing will be hidden): 
Authentication successful.

• cd into your Dropwizard project repo and create a new heroku project

$ heroku create mydropwizardapp
Creating example-app… done, stack is cedar
http://mydropwizardapp.herokuapp.com/ | [email protected]:mydropwizardapp.git
Git remote heroku added

• Allocate dyno resources & scale your web

$ git push heroku master
$ heroku ps:scale web=1

• Check your project at http://mydropwizardapp.herokuapp.com/ or at http://mydropwizardapp.herokuapp.com/, where * are your Resources with @Path set in /src/main/java/com/pkgname/resources/.java. You must register your resources under YourAppApplication.java (for example, see run method in /src/main/java/com/example/weatherbot/WeatherBotApplication.java

Notes for deployment on Heroku

• Procfile: For hosting on Heroku, you must ensure the project has a Procfile entry. Heroku will assume a Java build after finding pom.xml in the project root and run the commands in the Procfile. The procfile is in the following format: "web: java $JAVA_OPTS -Ddw.server.connector.port=$PORT -jar target/weatherbot-1.0.1-SNAPSHOT.jar server weatherbot.yml" Note the usage of $JAVA_OPTS and $PORT. $PORT is overridden by Heroku, and $JAVA_OPTS is set dynamically by heroku.
• weatherbot.yml: Here, database and server configurations are overridden by config variables in Heroku. To create a project with a database connection, set the DATABASE_URL config var with a "heroku config:set" command. Setting up your server configuration correctly can be done by making sure it mirrors -Ddw.server.connector.port command in your Procfile.