The Java microservice lib. QBit is a reactive programming lib for building microservices - JSON, HTTP, WebSocket, and REST. QBit uses reactive programming to build elastic REST, and WebSockets based cloud friendly, web services. SOA evolved for mobile and cloud. QBit is a Java first programming model. It uses common Java idioms to do reactive programming. It focuses on Java 8. It is one of the few of a crowded field of reactive programming libs/frameworks that focuses on Java 8. It is not a lib written in XYZ that has a few Java examples to mark a check off list. It is written in Java and focuses on Java reactive programming using active objects architecture which is a focus on OOP reactive programming with lambdas and is not a pure functional play. It is a Java 8 play on reactive programming. Services can be stateful, which fits the micro service architecture well. Services will typically own or lease the data instead of using a cache. CPU Sharded services, each service does a portion of the workload in its own thread to maximize core utilization. The idea here is you have a large mass of data that you need to do calculations on. You can keep the data in memory (fault it in or just keep in the largest part of the histogram in memory not the long tail). You shard on an argument to the service methods. (This was how I wrote some personalization engine in the recent past). Worker Pool service, these are for IO where you have to talk to an IO service that is not async (database usually or legacy integration) or even if you just have to do a lot of IO. These services are semi-stateless. They may manage conversational state of many requests but it is transient. ServiceQueue wraps a Java object and forces methods calls, responses and events to go through high-speed, batching queues. ServiceBundle uses a collection of ServiceQueues. ServiceServer uses a ServiceBundle and exposes it to REST/JSON and WebSocket/JSON. Events are integrated into the system. You can register for an event using an annotation @EventChannel, or you can implement the event channel interface. Event Bus can be replicated. Event busses can be clustered (optional library). There is not one event bus. You can create as many as you like. Currently the event bus works over WebSocket/JSON. You could receive events from non-Java applications. Find out more at: https://github.com/advantageous/qbit

1. Java microservice development for high-speed services
Java Microservice lib
QBit
high-speed, in-memory,
services for REST, WebSocket
and JSON

2. Java microservice development for high-speed services
What is QBit?
❖ Fast queue based service engine!
❖ Services sit behind high-speed queues!
❖ Uses micro-batching and mechanical sympathy to create high speed REST
and WebSocket microservice!
❖ Programming model looks like Spring MVC, but enables high-speed async
model like Akka, Vertx, Reactor, but easier to program!
❖ Uses Consul or Etcd for clustering, health, cloud config, elasticity !
❖ Has event bus that can use Kafka, 0Q, etc.!
❖ Uses JSON for wire protocol, works easily with any language over HTTP or
WebSocket

3. Java microservice development for high-speed services
Why QBit?
❖ Just a lib, does not take over the world!
❖ Works with Guice or Spring!
❖ Just POJOs written like Java developers write POJOs no steep
learning curve!
❖ FAST!!
❖ Easier than reactive, worker pools, sharded services and queued
services!
❖ Uses Consul for service discovery, WebSocket for high-speed
messaging and REST

4. Java microservice development for high-speed services
Architects / Developers of QBit
❖ Wrote high throughput global services for large high-traffic clients!
❖ F5 crushing load!!
❖ Implemented systems that took other systems 10x to 100x as many servers and 20x
#of developers that could handle only 1/10th of the traffic !
❖ Wrote JSON parser that is 4x faster than mainstream JSON parsers!
❖ Been there, done that for 20+ years. 100+ years building high-speed, reliable systems
combined!
❖ Consulting with airlines, plane manufacturers, banks, commodity trading, electronic
manufacturing, and other trading systems!
❖ Wrote services that powers some of the busiest sites on the Internet!
❖ Wrote fastest disk batcher for JVM, high-speed, distributed k/v store, in-memory db

5. Java microservice development for high-speed services
QBit Speed - FAST!
❖ 200 M in-proc messages a second!
❖ 10M to 100M in-proc events per second!
❖ 700K to 1,000,000 RPC calls!
❖ Equates to 1.4M to 2M messages TPS!
❖ Using JSON! One Service Thread! One WebSocket!!
❖ Not uncommon to use a fraction of CPU for 2x to 10x to
100x the same performance as a traditional microservice

6. Java microservice development for high-speed services
It all starts with a fast queue

7. Java microservice development for high-speed services
Speed First

8. Java microservice development for high-speed services
Service Discovery / Health
❖ Integration with Consul for
health and event bus wiring
of peers!
❖ Cloud config!
❖ Peer discovery!
❖ Health Checks!
❖ Serf/Dead man’s switch,
gossip, custom

9. Java microservice development for high-speed services
Ease of use and simplicity too

10. Java microservice development for high-speed services
What is QBit again?
❖ Java microservice development for high-speed services!
❖ JSON!
❖ REST!
❖ WebSocket!
❖ Services look like Spring MVC REST / JAX-RS !
❖ look like Spring Boot, Drop-wizard but work like Spring reactor, Akka, Go,
ErLang, etc. !
❖ Embraces microservices!
❖ Clients can be Web, Mobile, any language that has JSON lib, HTTP lib can use
QBit services

11. Java microservice development for high-speed services
QBit Services
❖ WebSocket RPC, HTTP REST, and in-proc messaging!
❖ In-proc, sits behind an actor style queue, gets notified of
queue empty, queue limit, queue init, queue start batch,
etc.!
❖ Allows reduction of sending IO or calls to CPU
intensive services in batches based on queue events!
❖ Batching calls increases system throughput through
the system 10x, 100x, 1000x.

12. Java microservice development for high-speed services
Key Concepts
❖ `!
❖ Queue !
❖ A thread managing a queue. !
❖ supports batching. !
❖ queue callbacks for empty, reachedLimit,
startedBatch, idle, etc.!
❖ ServiceQueue!
❖ POJO (plain old Java object) behind a
queue!
❖ receive method calls and events !
❖ thread safe!
❖ queue callback methods!
❖ Java idioms looks like Spring MVC REST,
JAX-RS!
❖ ServiceBundle !
❖ Many POJOs behind one response queue
and many receive queues.
❖ ServiceServer !
❖ Exposes services to REST/JSON and
WebSocket/JSON communication!
❖ EventBus !
❖ send a lot of messages to services !
❖ may be loosely coupled,!
❖ integration with others event buses
(Kafka, STOMP, etc.)!
❖ Metrics/Stats: track in-flow, and outflow
of messages, other metrics for
performance, high-speed time-series
database with REST interface!
❖ Meta-Data-Service: Publish track all
REST JSON schemas for easy integration
and use by third parties

13. Java microservice development for high-speed services
Principles of QBit
❖ Web first (JSON, HTTP, WebSocket)!
❖ Integration via high-speed event bus (Kafka, STOMP,
0MQ, ActiveMQ, etc.)!
❖ Embrace Mechanical Sympathy and Queue Theory to
optimize thread hand-off, IO, and core cross talk!
❖ Less is more (be the 95% solution leave the long tail
alone)!
❖ Fun and easy to use!

14. Java microservice development for high-speed services
QBit Service Example
Domain Object
Service
WebSocket HTTP support

15. Java microservice development for high-speed services
QBit Example
CURL-ABLE
JSON Output

16. Java microservice development for high-speed services
Service REST support
❖ Supports Request params, URI params, JSON POST,
HTTP GET, etc.!
❖ Customize URIs using annotation!
❖ Reasonable Defaults (annotations not needed)!
❖ Methods available via annotations

17. Java microservice development for high-speed services
QBit versus….

18. Java microservice development for high-speed services
QBit versus Spring XXX
❖ Spring what? DI? MVC? Boot?!
❖ QBit Works easily with DI and Spring Boot!
❖ Competes against Spring MVC but has better thread
model for high-speed services, but not all the “features”.!
❖ Spring MVC does a lot. QBit only does Microservices
only! So only JSON, REST, and WebSocket!
❖ QBit Enable writing in-memory, high-speed services that
can handle 200K TPS to 2M TPS per second single node

19. Java microservice development for high-speed services
Akka vs. QBit
❖ Akka uses actor model!
❖ QBit uses queuing actor-like model + active objects model!
❖ Akka focuses on Queue handlers!
❖ QBit focuses on Services that look / act like Java services in
Spring REST, JAX-RS, Java EE, and other frameworks!
❖ QBit is a Java centric model, Akka programming model is similar
but foreign to most Java developers!
❖ QBit center of gravity is Microservices = REST, JSON, WebSocket

20. Java microservice development for high-speed services
Akka and QBit similarities/differences
❖ Akka Typed Actor a lot like QBit Service!
❖ QBit Services can be exposed via REST/JSON or
WebSocket/JSON!
❖ Both use queue events (empty, init, limit, etc.) to optimize
output to IO!
❖ Both are fast!
❖ QBit is library and you can use / compose queues,
services as you see fit (you could use QBit in a Spring app)

21. Java microservice development for high-speed services
Node.js, Vertx
❖ Node.js and Vertx both use a Reactor style design pattern based on event bus.
(QBit is reactive but using active objects not reactor.)!
❖ At first glance looks a lot like Akka or QBit!
❖ Less granularity on bus, QBit bus speed is a lot faster!
❖ Less control of when queue is idle, empty, etc. QBit has Akka like tuning which is
critical to optimize around back pressure.!
❖ Vertx/Node.js are harder to optimize. Harder to compose other handlers. !
❖ Great for IO and Vertx can be combined with QBit to provide missing pieces for
Speed!
❖ Not bad. Not even close to what QBit can do!
❖ QBit works well with Vertx

22. Java microservice development for high-speed services
How does it do?
❖ Faster!
❖ Easier to use!
❖ Focuses just on Micorservices!
❖ Tolerant reader, promiscuous writers!
❖ Uses RAFT and Consul for service discovery

23. Java microservice development for high-speed services
Event Bus Overview

24. Java microservice development for high-speed services
Event Bus
❖ QBit has a high-speed event bus modeled loosely on Vertx style
event bus!
❖ Very fast. !
❖ In-proc but can be integrated with others!
❖ Service methods can be invoked by calls (remote and local behind a
queue) !
❖ Service methods can be invoked by listening to a event bus
channels!
❖ You can subscribe to channels or you can consume channels or both

25. Java microservice development for high-speed services
Composable Event Bus
❖ EventBus can be composed!
❖ You can use the system event bus for in-proc service to service
messaging!
❖ You can remote replicate events to other servers!
❖ You can tap into an event bus, and/or post events to a service
directly for integration with 3rd party systems like Kafka, 0MQ,
etc.!
❖ You can use Consul integration to find service peers and
compose event bus that allows peers to communicate

26. Java microservice development for high-speed services
Event Bus is an Integration point
❖ Event bus is an integration point!
❖ Can be easily integrated with Camel, ActiveMQ, JMS,
Kafka, etc.!
❖ Events come in on same queue as method call!
❖ Event Bus can do remote broadcast and can discover
peers via Consul or Etcd

27. Java microservice development for high-speed services
QBit Event Bus

28. Java microservice development for high-speed services
Private event bus versus System event bus
❖ Private event bus!
❖ https://github.com/advantageous/qbit/wiki/%5BRough-Cut%5D-Working-
with-private-event-bus-for-inproc-microservices!
❖ Only your module uses it!
❖ System event bus!
❖ https://github.com/advantageous/qbit/wiki/%5BRough-Cut%5D-Working-
with-event-bus-for-QBit-the-microservice-engine!
❖ Used by default if you don’t define your own!
❖ Event buses are composable!
❖ events are intrinsic to Services and event buses can be wired to services and
other event buses

29. Java microservice development for high-speed services
Simple Example
Java 8 Lambda
Annotation Based
Send
Consumer
Subscriber

30. Java microservice development for high-speed services
More involved Example
❖ Advantage of using the event bus with QBit services is the events come into
same queue that handles method calls so events method calls are thread
safe!
❖ Event Bus is very fast. Expect speeds up to 10M to 100M messages a second.!
❖ New example: set of services that handles when a new employees is hired!
❖ Add the employee to payroll system, !
❖ Enroll employee into benefits system!
❖ Invite employee to our community outreach program!
❖ Four services but the first service will not know about other services

31. Java microservice development for high-speed services
Channels and Employee

32. Java microservice development for high-speed services
EmployeeHiringService

33. Java microservice development for high-speed services
Service that listen

34. Java microservice development for high-speed services

35. Java microservice development for high-speed services
Getting a client proxy to a service

36. Java microservice development for high-speed services
Services are just POJOs

37. Java microservice development for high-speed services
Wire in POJOs services

38. Java microservice development for high-speed services
Create a client proxy from service

39. Java microservice development for high-speed services
Add a new Service Listener?

40. Java microservice development for high-speed services
New Service

41. Java microservice development for high-speed services
Event Manager
❖ You can use a private event bus instead of a system
event bus!
❖ You can use strongly typed proxy to the event bus to
abstract channel names and provide a strongly typed
bus

42. Java microservice development for high-speed services
Strongly Type Interface

43. Java microservice development for high-speed services
Using strongly typed interface to event bus

44. Java microservice development for high-speed services
Using Strongly typed Event Proxy

45. Java microservice development for high-speed services
Using Strongly Typed Event Proxy-WIRING

46. Java microservice development for high-speed services
Working with callbacks
https://github.com/advantageous/qbit/wiki/%5BRough-Cut%5D-QBit-Microservice-Lib-
Working-With-CallBacks

47. Java microservice development for high-speed services
Callbacks

48. Java microservice development for high-speed services
Recommendation service callback

49. Java microservice development for high-speed services
ServiceQueue Proxy for service

50. Java microservice development for high-speed services
Recommendation service

51. Java microservice development for high-speed services
Handling a callback

52. Java microservice development for high-speed services

53. Java microservice development for high-speed services

54. Java microservice development for high-speed services
Lambdas are great until you can’t read your code anymore
Lambda calling Lambda, calling
Lambda calling Lambda.!
!
Stop using Lambda if your code
starts to look like Perl threw up on
Lisp.!
!
One, to three levels ok.!
!
Five or six, can you break this out
into a method call or two.

55. Java microservice development for high-speed services
Don’t forget to flush
Auto flushing is available
too!

56. Java microservice development for high-speed services
But gee what if we have to load the user data?
❖ The first rule is don’t block!
❖ Services can call other services!
❖ When a service might do IO then it should take a
callback instead of have a return (generally speaking)

57. Java microservice development for high-speed services

58. Java microservice development for high-speed services
Use Callback instead of blocking

59. Java microservice development for high-speed services
If user is loaded, just call callback

60. Java microservice development for high-speed services
If you need to load the user, do it async…

61. Java microservice development for high-speed services
Doing something later…, but not too much later

62. Java microservice development for high-speed services
Async procrastination a good thing…

63. Java microservice development for high-speed services
When to handle callbacks?
When your queue is
empty, !
when you hit your
queue limit,!
and !
perhaps at the start !
of a new message
batch?!
!
Handle callbacks
before handling new
method calls so
clients don’t wait
around with open
connections

64. Java microservice development for high-speed services
Workers for IO, Sharded Services for CPU
❖ QBit allows worker pools for IO bound workers!
❖ QBit allows sharded for CPU bound workers that work
on in-memory data!
❖ Or just regular workers!
❖ Queue system can detect when CPU bound services are
busy and auto-increase queue batch size