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BUILDING APPLICATIONS
WITH AKKA.NETANTHONY BROWN
@BRUINBROWN93
moore’s law
now we need
concurrency…
…but concurrency is hard
MULTITHREADING
THEORYPRACTICE
CHECK OUTMY MULTITHREADED CODE
HOW MANY THREADSDOES IT TAKE TO CHANGE A LIGHTBULB?
application requirements have changed
Credit: http://www.theawl.com/wp-content/uploads/2010/08/Screen-shot-2010-08-17-at-2.11.10-PM.png
Common language to define new style of architecture
Reactive systems
RESPONSIVE
RESILIENT ELASTIC
MESSAGE PASSING
responsive
users want the best possible experience
reactive applications react
to the world around them
Message driven architecture
decouples components
the actor model
concurrency model
STORAGE isolate mutable state
processing reacting to changes
Communication messaging as a requirement
an actor is
A mailbox behaviour state
an actor can…
set it’s behaviour for the next message
an actor can…
send a finite number of messages
an actor can…
spawn a finite number of actors
looking at the original
erlang
99.9999999% uptime
erlang example
introducing the akka.net way
step 1
define an actor
class GreetingActor : ReceiveActor { public GreetingActor() { Receive<string>( s => Console.WriteLine(“Hello ” + s)); } }
step 2
create an actor
var system = ActorSystem.Create(“GreeterSystem”);
var greeterActor = system.ActorOf<GreeterActor>();
greeteractor isn’t something you can call
normally
it’s a reference to an actor
where is my actual actor?
AKKA.net
root actor
your
actors
Addressable like a file system or web site
akka://Greetersystem/user/parent/child
step 3
send a message
greeter.Tell(“DDDSW”);
step 4
change behaviour
Visual studio based demo
resilience in reactive systems
WE want applications to
ISOLATE ERRORS
SELF HEAL
your users don’t want to see THIS
Service aService B
supervisor
Request
Response
user error
error action
scalability in reactive systems
scale up has a ceiling
scale out doesn't
and it’s easy if you share nothing
how do we handle increased load?
pools of actors
visual studio based demo
how do we use akka.net
the internet of things
what is the Iot?
pointless
A security nightmare
i really don’t want to be facebook
friends with my toaster
managing farms
some things we saw
actors are cheap
DON’t worry about having too many
Always take back pressure seriously
LIBRARIES LIKE POLLY HELP
LET IT CRASHdon’t worry about catching all
exceptions
message passing is harder to debug
use akka.testkit to comprehensively
test
understand message delivery guarantees
at most once is default
at least once is an option
IN conclusion
akka.net gives us lots
Auto-scaling
Service discovery
SELF HEALING
CLUSTERING SUPPORT
CQRS
MESSAGE PASSING LOCATION TRANSPARENCY
CONFIGURATION
MAKES IT EASIER TO build reactive systems
understand the difficulties
where next?
WANT TO contribute?
github.com/akkadotnet/akka.net
gitter.im/akkadotnet/akka.net
want some help?
https://petabridge.com
HTTPS://github.com/petabridge/akka-bootcamp
read the book
http://manning.com/brown2
coming later this year
Q&A
