This document provides an overview of using Dropwizard, an open-source Java framework, to build RESTful web services. It discusses REST concepts like resources and representations, REST verbs like GET and POST, and architectures for REST APIs. It then introduces Dropwizard and its components for building HTTP services with features like Jetty, Jersey, Jackson, and metrics support. The document demonstrates a sample Dropwizard TODO list application with REST endpoints and resources and discusses considerations for development, testing, and deployment.

1. Simple REST with
Dropwizard
Intro, Structure, Resources, Deployment
Bucharest JUG #5 @ Cegeka

2. Andrei Savu
Founder @ Axemblr.com
Apache Whirr PMC member
jclouds committer
Connect with me on LinkedIn

3. Disclaimer
Highly Technical, Opinionated Talk

4. REST
(Representation State Transfer)
Browser Analogy: Fetch representation of the
current state of a resource (page)
Makes extensive use of HTTP semantics

5. Resource & Representation
Resource = the real thing
Representation = server responses
"A request interacts with a resource and
receives a representation."

6. REST Verbs
Match HTTP semantics:
● GET : read resources, safe, cache friendly
● POST : update resources, create
● PUT : replace entire resource, atomic
● DELETE : delete entire resource, atomic
● HEAD
● PATCH

7. REST Batch Operations
A request can act on a single resource or a
class of resources.
E.g.
POST /todos/1 {'email', 'new@example.com'}
POST /todos?email=x {'email': 'other@x.com'}

8. REST Transport
HTTP
With representations as JSON or XML
Negotiation with Accept & Content-Type
headers
Supports caching, If-Modified-Since queries

9. Architectures #1
Web UI
Database
API

10. Architectures #2
Web UI
API Database
Mobile

11. Architectures #3
Web UI Database
Internal
API Platform Queues
APIs
Mobile Other

12. Dropwizard
Thanks Yammer (Coda Hale) for making it
open source!
Framework for JVM-based backend services
"Dropwizard has out-of-the-box support for sophisticated configuration,
application metrics, logging, operational tools, and much more, allowing you
and your team to ship a production-quality HTTP+JSON web service in the
shortest time possible."

13. Components
● Jetty for HTTP
● Jersey for REST
● Jackson for JSON
● Metrics for metrics
● And: guava, logback, hibernate validator,
jersey client libraries, jdbi, freemarker
http://dropwizard.codahale.com/getting-started/

14. Demo Application
Structure, Configuration, Deployment

15. Specification
"A simple todo list sample application implemented using
Dropwizard as the core framework with a simple UI that
consumes the REST API based on twitter bootstrap,
backbone.js, jquery and jasmine."
https://github.com/bucharest-jug/dropwizard-todo

16. REST Endpoints
GET /todos | GET /todos/{id}
POST /todos
PUT /todos/{id}
DELETE /todos | DELETE /todos/{id}

17. Resources: Todo List
● id : assigned by server on creation (Read
Only)
● created : assigned on creation
● email: owner email address
● items: list of items

18. Resources: Todo Item
● title: a text description of what need to be
done
● created: date time assigned on creation
● finished: date time assigned when the item
was finished

19. To the IDE!
Structure, Configuration, Testing

20. Production Configuration
Dedicated repository with restricted access.
Cool tool: etckeeper (debian)

21. Deployment: Start Simple
Run tests on the local machine
Fabric / Capistrano
Supervisor / Upstart
Monit
Ganglia / Nagios / Cloudwatch / SNS

22. Deployment: Automate
Continuous Integration
Puppet / Chef
1-step deployment from a specific branch
Ability to rebuild from a vanilla OS install
Leverage cloud infrastructure for Dev & QA

23. Deployment: Continuous
High quality test suite (unit + live + smoke)
Continuous Deployment Pipeline
All new code is deployed to multiple
environments and production.
OpenAgile Timisoara anyone?

24. Resources
● Demo code:
https://github.com/bucharest-jug/dropwizard-todo
● All about Dropwizard:
http://dropwizard.codahale.com/
● API Grove: API management:
http://apigrove.net/

25. Thanks!
asavu@apache.org