jboner

Akka Cluster Implementation Notes

Slightly disorganized but reasonably complete notes on the algorithms, strategies and optimizations of the Akka Cluster implementation. Could use a lot more links and context etc., but was just written for my own understanding. Might be expanded later.

Links to papers and talks that have inspired the implementation can be found on the 10 last pages of this presentation.

Akka Gossip

Gossip state

This is the Gossip state representation:

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/*
Copyright 2012 Twitter, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software

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lost(arg, function(err, result) {
    if(err) return console.log(err);
    In(result, function(err, result) {
        if(err) return console.log(err);
        callback(result, function(err, result) {
            if(err) return console.log(err);
            hell(result);
        });
    });
});

jboner

import akka.actor._
  import java.net.InetSocketAddress
  import akka.util.ByteString

  class SimpleClient(destAddress: InetSocketAddress) extends Actor {

    val socket = IOManager(context.system) connect (destAddress)

    val state = IO.IterateeRef.sync()

jboner

Typesafe Project & Developer Guidelines

These guidelines are meant to be a living document that should be changed and adapted as needed. We encourage changes that makes it easier to achieve our goals in an efficient way.

These guidelines mainly applies to Typesafe’s “mature” projects - not necessarily to projects of the type ‘collection of scripts’ etc.

General Workflow

This is the process for committing code into master. There are of course exceptions to these rules, for example minor changes to comments and documentation, fixing a broken build etc.

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jboner at sarek in ~/src/akka-stuff/akka on master
[130] $ cloc .                                                                                                                                                           5244 text files.
    2647 unique files.                                          
    3822 files ignored.

http://cloc.sourceforge.net v 1.56  T=52.0 s (41.8 files/s, 13040.5 lines/s)
--------------------------------------------------------------------------------
Language                      files          blank        comment           code
--------------------------------------------------------------------------------
HTML                           1473          39655              1         529371

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Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

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--langdef=Scala
--langmap=Scala:.scala
--regex-Scala=/^[ \t]*class[ \t]*([a-zA-Z0-9_]+)/\1/c,classes/
--regex-Scala=/^[ \t]*object[ \t]*([a-zA-Z0-9_]+)/\1/o,objects/
--regex-Scala=/^[ \t]*trait[ \t]*([a-zA-Z0-9_]+)/\1/t,traits/
--regex-Scala=/^[ \t]*case[ \t]*class[ \t]*([a-zA-Z0-9_]+)/\1/r,cclasses/
--regex-Scala=/^[ \t]*case[ \t]*object[ \t]*([a-zA-Z0-9_]+)/\1/r,cobjects/
--regex-Scala=/^[ \t]*abstract[ \t]*class[ \t]*([a-zA-Z0-9_]+)/\1/a,aclasses/
--regex-Scala=/^[ \t]*def[ \t]*([a-zA-Z0-9_=]+)[ \t]*.*[:=]/\1/m,methods/
--regex-Scala=/[ \t]*val[ \t]*([a-zA-Z0-9_]+)[ \t]*[:=]/\1/V,values/

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{
    "cmd": ["sbt-no-color compile"],
    "file_regex": "^\\[error\\] ([.a-zA-Z0-9/-]+[.]scala):([0-9]+):",
    "selector": "source.scala",
    "working_dir": "${project_path:${folder}}",
    "shell": "true"
}

jboner

package com.earldouglas.remoteakka

import akka.actor.Actor
import akka.actor.Actor._

case object Greeting
case class Jar(val bytes: Array[Byte])
case class RegisterRemote(val name: String, val className: String)

object Runner {