nraychaudhuri

title	description	link
Scaling Pinterest • Marty Weiner • GOTO 2014	This presentation was recorded at GOTO Aarhus 2014http://gotocon.comMarty Weiner - Cloud Ninja @ PinterestABSTRACTIt's been an amazing ride building Pinteres...	https://www.youtube.com/watch?v=

nraychaudhuri

sealed trait UrinalStatus { def value: String }

final case object Available extends UrinalStatus  {
  val value = "Avialable"
}

final case object Occupied extends UrinalStatus  {
  val value = "Occupied"
}

nraychaudhuri

Keybase proof

I hereby claim:

• I am nraychaudhuri on github.
• I am nilanjan (https://keybase.io/nilanjan) on keybase.
• I have a public key whose fingerprint is E5FB 9991 27E0 074C D2B7 7EF0 8CC4 C3BC B9D5 87B6

To claim this, I am signing this object:

nraychaudhuri

private void busy(FiniteDuration duration) {
  pi(duration.toMillis() * 800);
}

private BigDecimal pi(long m) {
  int n = 0;
  BigDecimal acc = new BigDecimal(0.0);
  while(n < m) {
    acc = acc.add(gregoryLeibnitz(n));
    n += 1;

nraychaudhuri

import akka.actor.ActorIdentity;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.event.Logging;
import akka.testkit.JavaTestKit;
import akka.testkit.TestProbe;
import com.typesafe.training.coffeehouse.CoffeeHouse;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

nraychaudhuri

//PLEASE NOTE: Typing actor refs are really hard problem(take a look at the discussions in Akka mailing list regarding this subject). This is no way a complete solution. This will only work if you know all the possible
//messages an actor can handle (that means no become/unbecome business).

package experiment

import akka.actor.{Props, ActorSystem, Actor, ActorRef}

case class TypedActorRef[A](actorRef: ActorRef) extends AnyVal {
  def ![B](msg: B)(implicit ev: A <:< B, sender: ActorRef = Actor.noSender) = actorRef ! msg
}

nraychaudhuri

I try to put things into the larger perspective here, so prepare, long mail.

== Defining backpressure

First of all, we need a working definition of "backpressure". I put it in quotes since I will attack things from a very general perspective which might not exactly match what others think as backpressure.

Sometimes it is easier to characterize the correct behavior of a system/protocol by defining what we consider incorrect behavior rather than trying to limit ourselves when approaching from correctness properties. In the case of backpressure there are two undesireable kinds of behavior:

 - If the buffers in the system might growth without bounds then the backpressure protocol is not safe
 - If the protocol can become stuck, although the sender has messages to deliver and the receiver is also available to process them, then the backpressure protocol is not safe

nraychaudhuri

The default SupervisorStrategy in Akka

At times it's hard to remember all the details of restarting a faulty actor. So lets take a look at a simple example:

/user/grand-parent/parent/child

Here we have a Child actor with one Parent and one GrandParent actor.

nraychaudhuri

package solution

import scala.slick.driver.ExtendedProfile

object DI {

  object models {
    sealed trait Model { def id: Option[Long] }
    case class ModelA(a: String, id: Option[Long] = None) extends Model
    case class ModelB(b: String, id: Option[Long] = None) extends Model

nraychaudhuri

//Trait that bridges between slick and Play2-auth. Just mixin with controllers
trait Auth2SlickBridge {
  self: StackableController =>

  def AuthAction[A](p: BodyParser[A], params: (RequestAttributeKey[_], Any)*)(f: RequestWithAttributes[A] => Action[A]): Action[A] = {
    AsyncStack(p, params:_*) { implicit rs =>
      f(rs).apply(rs)
    }
  }