Reactive programming is an asynchronous programming paradigm, concerned with streams of information and the propagation of changes. This differs from imperative programming, where that paradigm uses statements to change a program’s state. Reactive Architecture is nothing more than the combination of reactive programming and software architectures. Also known as reactive systems, the goal is to make the system responsive, resilient, elastic, and message-driven.

1. REACTIVE
ARCHITECTURE
Presented By: Piyush Rana
Lead Consultant
Knoldus Inc.
LEARN NOW

2. About Knoldus
Knoldus is a technology consulting firm with focus on modernizing the digital systems
at the pace your business demands.
DevOps
Functional. Reactive. Cloud Native

3. 0110:30 AM What is Reactive?
0210:45 AM Challenges
0311:00 AM Reactive Principles
0411:30 AM Actor based
Concurrency
0512:00 PM Wrap Up : Final
Conclusion
Our Agenda

4. Published
Published on September 16
2014. (v2.0)
Execute
To make Reactive Systems
Optimize
Scale up and Scale Down
Monitor
easier to develop and
amenable to change
Model
more robust, more resilient,
more flexible and better
positioned to meet modern
demands.
What is Reactive Architecture

5. Sign The
Reactive
Manifesto
To support the reactive architecture and
join with the community and group one
can read and then join the manifesto.
Sign Now

6. Users
in 1999 : -
The Internet had 280 million users.
J2EE just started by of Sun
Microsystems.
Online banking was in its infancy — 5
years old, give or take.
Parallelism
A few other fun factoids:
The Internet had 1 billion users.
Facebook had 5.5 million users.
YouTube was a newborn (February,
2005).
Twitter wasn’t alive yet (2006).
Netflix had yet to introduce video
streaming (2007).
Communication
Times have changed. A single
website may now handle as much
traffic as the entire Internet did less
than a decade ago.
The two major game changers for
developers and companies are:-
- Advancements in hardware.
- The Internet.
20XX
Speed
Problem Or Challenges???

7. Time Vs Technologies
Total users of the Internet, Facebook, and Twitter, from 1995 to 2015.

8. OUR MISSIONInsert Your Subtitle HereReactive applications are built on four guiding principles.
Description
A resilient system applies proper design and architecture principles
in order to ensure responsiveness under grey skies as well as blue.
Resilient
A scalable system is easily upgraded on demand in order to
ensure responsiveness under various load conditions.
Scalable
A message-driven architecture is the foundation of Reactive
applications. A message-driven application may be
event-driven, actor-based, or a combination of the two.
Message-Driven
Reactive Principles

9. Resilience
Always Up and
Responsive in
negative scenarios
Scalability
With Heavy Loads
comes the heavy
responsibility
Message-driven
asynchronous
boundary that
decouples you from
time and space.
A responsive system is quick to react to all users — under blue skies and
grey skies — in order to ensure a consistently positive user experience.
Responsive

10. The previous version was
pain the ----?
I think Stil… Check their site
on your mobile
Same try the mobile
version.
All most all, or either they are
static not at all responsive!!
1
2
3
4
IRCTC
Tata Docomo
Shoppers
Stop
Gov Websites
Let’s Play a game, how
many of you have gone
through some website
that are not responsive?

11. ABOUT COMPANYA resilient system applies proper design and architecture principles in order to
ensure responsiveness under grey skies as well as blue.
Description
Resiliency Increases Responsiveness !!!
Isolation is needed for a system to
self-heal.
Isolation
Location transparency gives us the ability to
interact with different processes on different
cluster nodes just like we do in-process on
the same VM.
Location transparency
A dedicated separate error channel
Resilient

12. www.website.com
Consider the software glitch
experienced by Knight Capital Group in
2012.
2012 It cost the company 440 million
dollars to reverse.
During a software upgrade, another dormant, integrated
application was inadvertently fired up and began amplifying
trading volumes.
2012
Not so Resilient
- Mistake

13. ABOUT COMPANYA scalable system is easily upgraded on demand in order to ensure
responsiveness under various load conditions.
Description
Resiliency and scalability go hand-in-hand
Some popular MVC frameworks like
Rails are thread-based
Thread-based concurrency
Scaling up Or Scaling Out?
Out or up?
Reactive applications are difficult to build with
thread-based frameworks because of how
difficult it is to scale out an application based
on shared mutable state, threads, and locks.
Scalable

14. Lower infrastructure
costs
Less cheap commodity
hardwares and less
protection cost
40%
Achieve greater
resiliency and
availability
erasure encoding to ensure
that data is available, even if
drive or node failures occur
and good for For disaster
recovery
40%
Performance
Improvement
Think what a single system s
can do adn what 10 systems
can do for the same work?
15%
Provide self-service
solutions
Scale-out infrastructures that utilize a
unified data protection platform can
automate and orchestrate complex tasks,
leading to improved efficiency and
minimized risk of human error.
5%
Advantages of Scale Out Systems

15. Insert Your Subtitle Here
Reactive Programming can be
used to support the
construction of
Reactive Systems.
Reactive Programming can be
used to support the
construction of
Reactive Systems.
Reactive Programming can be
used to support the
construction of
Reactive Systems.
Reactive Systems apply Reactive
Principles to architecture.
Reactive Systems apply Reactive
Principles to architecture.
Reactive Systems apply Reactive
Principles to architecture., e.g
reactive microservices
Reactive Programming Vs System

16. THE CAP THEOREM

27. Actor based
Messages may cross
thread boundaries or
be passed to another
actor’s mailbox on a
different physical
server.
Event Driven
This is different than
imperative
programming
because the caller
doesn’t need to block
waiting for a response
from the invoked
routine.
Actor Based
where messages are
directed to a recipient
Event Driven
based on events which
are monitored by zero
or more observers.
Message Driven
A message-driven architecture is the foundation of Reactive applications. A message-driven application may
be event-driven, actor-based, or a combination of the two.

28. ABOUT COMPANYActor-based applications revolve around asynchronous message passing
between multiple actors.
An actor is a construct with the following properties:
Description
For reactive, concurrent, and distributed applications
A mailbox for receiving messages.
Message Box
The actor’s logic, which relies on pattern
matching to determine how to handle each
type of message it receives.
Actor Logic
Rather than shared state — for
storing context between requests.
Isolated State
Akka Actor

29. The challenge of encapsulation Objects can
only guarantee encapsulation (protection of
invariants) in the face of single-threaded
access, multi-thread execution almost always
leads to corrupted internal state.
The illusion of shared memory There is no real
shared memory anymore, CPU cores pass
chunks of data (cache lines) explicitly to each
other just as computers on a network do
The illusion of a call stack To achieve any
meaningful concurrency and performance on
current systems, threads must delegate tasks
among each other in an efficient way without
blocking.
Concurrency
Actor
Based
01
03
Let’s Understand This More!
02

30. OUR CHARTInsert Your Subtitle Here
One can also learn more and can obtain certification from below
resources
https://cognitiveclass.ai/courses/reactive-architecture-intro
duction
Cognitive Classes Course
https://www.lightbend.com/services/training/lightbend-reactive-a
rchitecture-professional
Lightbend Reactive Architecture - Professional
https://akka.io/
Programming
Be Reactive !

31. Fast Data
Ecosystem
Kafka
Ecosystem
Deployment &
Monitoring
Continuous
Integration
Functional
Ecosystem
Knoldus Tech Stack

32. OUR CHARTInsert Your Subtitle Here
https://www.lightbend.com/learn/lightbend-reactive-architecture
https://readwrite.com/2014/05/08/gilt-eric-bowman-interview-scala-rails-jvm-reactive-platform/
https://money.cnn.com/2012/08/06/investing/knight-capital-agreement/index.htm
Reference

33. Thank You!
@DameonDead
@piyush_neutrality
piyush.rana.3150