Game On! (@gameontext – http://game-on.org) is an awesome throwback text-based adventure built with microservices. Completely open source, it enables everyone to choose their own adventure to learn about microservices concepts while extending the game. One of the core services is the Map, which maintains a two-dimensional map containing all the registered rooms. The Map started with a document store as a back end, but as the Map changed over time, tombstones started to accrue. And then people started to ask how to manage three dimensions, and dragons appeared. Come to this session to find out why the decision was made to change the NoSQL back end, how it was done, and the result of the change with a new NoSQL API (http://jnosql.org/).

1. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Choosing a NoSQL API and Database
to Avoid Tombstones and Dragons
in Game On!
Leonardo Lima Otávio SantanaKate Stanley

2. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
About the Speakers
Katherine (Kate) Stanley
• Software Engineer, works for IBM
• From United Kingdom
• Work on Java development for IBM Cloud
• Committer to Game On
• Contributed to MicroProfile conference app
• Co-wrote IBM Redbook about Microservices with Java

3. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
About the Speakers
Leonardo Lima
• Computer engineer, server & embedded sw developer
• From São Paulo, Brasil, currently in Austin, TX
• CTO at V2COM
• Spec Lead – JSR363 – Units of Measurement
• V2COM’s Representative at JCP Executive Committee
[about.me/leomrlima]

4. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Otávio Santana
• Software engineer, Tomitribe
• From Salvador, Brazil
• Java Champion, SouJava JUG Leader
• Apache, Eclipse and OpenJDK Committer
• Expert Group member in many JSRs
• Representative at JCP EC for SouJava
About the Speakers

5. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Microservices &
GameOn!

6. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Microservices are used to…
— … compose a complex
application using:
◦ “small”
◦ independent (autonomous)
◦ replaceable
◦ processes
— … that communicate via
language-agnostic APIs
Microservice
MicroserviceMicroservice
Microservice
Microservices application
Subscribe
REST
(JSON/HTTP)
Microservice
Microservice
broker
API
Microservice
Publish
API
REST
(JSON/HTTP)
Publish
Service
Registry
API
Microservice

7. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Microservices sample apps…
Create a single service
Rebuild a pre-baked microservices application
Clueless
No idea
Confident
Has read all the
things!
Experienced
Hands-on understanding
Puzzled / Realistic
Challenges are real

8. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Enter… GameOn!
— Hands on with microservices
— Stick with ’HelloWorld’ simplicity
— Choose your own adventure
— Fast path to the hard stuff
— Build something cool (to you!)
— Learn as you go

9. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Twelve Factors
— “a methodology for building
software-as-a-service
applications”
◦ Created by developers at Heroku
— Factors are independent of
◦ programming language,
◦ backing services,
◦ cloud provider
— http://12factor.net/

10. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
At first…
ELK mongo
room
Player
Proxy
JSON/HTTP (REST)
Concierge

11. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
… and now!
kafkaELK amalgam8couchdb
room
PlayerAuth
SweepProxystatic
MediatorMap

12. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
About Dragons and Tombstones
— Problem: Maintaining a centered,
densely packed grid of rooms
— SQL is hard.
— CouchDB uses javascript to create
custom indexes
— BUT: Deleting rooms leaves
tombstones.They never go away.

13. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
The Map API
— Site has Name, Position (X,Y),
Connection information to the
WebService and a list of its
Doors.
— CRUD service; when you
retrieve a room, you get a list
of its adjacent rooms

14. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
The Map API
{
"name":"First Room",
"connectionDetails":{
…, "target":"ws://secondroom:9008/barn/ws",
… },
"fullName":"The First Room",
"description":"A helpful room with doors in every possible direction.",
"repositoryUrl":"https://github.com/your-fork",
"doors":{
"n":"A knobbly wooden door with a rough carving or a friendly face",
"w":"A fake wooden door with stickers of friendly faces plastered all over it",
"s":"A warped wooden door with a friendly face branded on the corner",
"e":"A polished wooden door with an inlaid friendly face",
}
}

15. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
The Map Internals, version 1
— Literally a copy of what’s exposed
— Hard to store references to other rooms
— Room pre-allocation and movement make it cumbersom
— No way to (really) delete rooms (!)

16. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Map.stream().toGraph()
— A Map is a Collection of Rooms connected thru Doors
— X connected toY is… a graph!

17. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
A graph, really?
First
Room
Play
Room
Basement
Dungeon

18. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Take 1: Neo4J
— Created rooms using Neo4J APIs and Cypher query language
— No easy way to do CRUD operations
◦ Convert from object to Cypher using inspection
— In the end, just changing who was holding our chain…

19. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Take 2: JNoSQL!

20. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
What is JNoSQL?
— Mapping API - Artemis
— Communication API - Diana
— No lock-in
— Divide and conquer
DAO
Communication
Mapping
JNoSQL

21. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Eclipse JNoSQL
— Eclipse Foundation
— Apache v2 + EPL 1.0
— API to each NoSQL type
— Configurable
— Extensible Communication
Mapping

22. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
JNoSQL – Diana APIs
Key/Value Document
Column
Family
Graph

23. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Names & Definitions
— Annotated Entities
— Template
— Repository
— Configuration

24. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Annotaded Entities
— MappedSuperclass
— Entity
— Column
@Entity
public class Site {
@Id
private Long id;
@Column
private String name;
…
}

25. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Template
@Inject
private GraphTemplate template;
public Optional<Site> getRecentRoom() {
return template
.getTraversalVertex()
.has("doorAvailable", true)
.<Site>stream()
.sorted(ORDER_WEIGHT)
.findFirst();
}

26. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Repository
public interface SiteRepository extends Repository<Site, Long> {
Optional<Site> findByName(String name);
}
@Inject
@Database(GRAPH)
private SiteRepository repository;

27. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Repository
@Transactional
public void save(Site site) {
if (isNull(site.getId())) {
Optional<Site> siteByName = repository.findByName(site.getName());
siteByName.ifPresent(site::merge);
}
repository.save(site);
}
public Optional<Site> findByName(String name) {
return repository.findByName(name);
}

28. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
The future & possibilities

29. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Why a graph makes MUCH sense?
— Current 2D map isVERY limiting
◦ With a graph we can go 3D!
— Different kinds of objects can be tracked:
◦ Items can be made unique and migrate
— Other doors are possible!

30. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Why a graph makes MUCH sense?
First
Room
Play
Room
Basement
Dungeon
The
One
Ring
Suite

31. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Get involved!
— https://gameontext.slack.com
— https://gameontext.org
— http://jnosql.org
— https://github.com/leomrlima/gameon-graph-map

32. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
? & !

33. GameOn!+JNoSQL
#JavaOne #JNoSQL @KateStanley91 @leomrlima @otaviojava
Thanks!