erlang for five nines

Erlang for Five NinesErlang for Five Nines

barbarcampcampCork IIICork III

Tamas [email protected]

© 1999 – 2009 Erlang Training and Consulting Ltd© 1999 – 2009 Erlang Training and Consulting Ltd

ContentsContents

• Erlang HistoryErlang History• Erlang HighlightsErlang Highlights• ProductsProducts• QuestionsQuestions

Erlang History: The Telecom IndustryErlang History: The Telecom Industry

• ComplexComplex• ReliableReliable• ScalableScalable• DistributedDistributed• MaintainablMaintainabl

ee• HighlyHighly

AvailableAvailable

• versusversus

Time To Time To Market!Market!

Access transport and switching networks

CellularPLMN

PSTN/ISDN

Data/ IPNetworks

CATV

Services

Past Single-service networks

Clients/applications

PresentMultiservice networks/client server

BackboneNetwork

Access

Access

Access

Content Content

ControlCommunication

applicationsMedia

Gateways

Erlang HistoryErlang History

1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

Prototypes of Telecom

applications

First projects launched

First products launched

Major projects started

OTP R1 released

Releasedas Open Source

Experiments started at the

Computer Science Lab

“Find the right methods - design by prototyping.”

Mike Willliams, CS LAB

Make mistakes on a small scale, not in a production project.

Mike Willliams

It’s not good enough to have ideas – you must also be able to implement them to

know that they work

Mike Willliams

And the rest is history...

First Erlang Book Published

First C-Based Virtual Machine

And this is just the beginning...

“Erlang is going to be a very important language.It could be the next Java.”

Ralph JohnsonCo-author, “Design Patterns” (the “Gang-of-Four book”)

To build a large scale message handling system that really had to be up all the time, I would unhesitatingly choose Erlang….

Tim BraySun Microsystems

…if we had to start again we would probably use Erlang…

Mike ShaverMozilla Foundation

Erlang HistoryErlang History

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 The Future

January, 36,000 hits on

erlang.org

Bluetail AB acquired for 152M USD

August, 1 million hits on

erlang.org

Erlang R11 goes multicore

The first Erlang Factory

Major new projects started within Ericsson

ETC is founded

Requests to erlang.orgRequests to erlang.org

ContentsContents


Erlang HighlightsErlang Highlights

• DeclarativeDeclarative• ConcurrencyConcurrency• Soft real-timeSoft real-time• RobustnessRobustness• DistributionDistribution• Hot code loadingHot code loading• External interfacesExternal interfaces• PortabilityPortability• SMP SupportSMP Support

Functional programming language

High abstraction levelPattern matching

Concise readable programs

Erlang Highlights: FactorialErlang Highlights: Factorial

n! =1

n*(n-1)!

n = 0

n 1

Definition

-module(ex1).-export([factorial/1]).

factorial(0) -> 1;factorial(N) when N >= 1 -> N * factorial(N-1).

Implementation

Eshell V5.0.1 (abort with ^G)1> c(ex1).{ok,ex1}2> ex1:factorial(6).720

Factorial using Recursion

Erlang Highlights: High-level Erlang Highlights: High-level ConstructsConstructs

-define(IP_VERSION, 4).-define(IP_MIN_HDR_LEN, 5).

……DgramSize = size(Dgram), <<?IP_VERSION:4, HLen:4, SrvcType:8, TotLen:16, ID:16, Flgs:3, FragOff:13, TTL:8, Proto:8, HdrChkSum:16, SrcIP:32, DestIP:32, Body/binary>> = Dgram, if (HLen >= 5) and (4*HLen =< DgramSize) -> OptsLen = 4*(HLen - ?IP_MIN_HDR_LEN), <<Opts:OptsLen/binary, Data/binary>> = Body, ….. end.

Parsing an IP Datagram using the Bit Syntax



Either transparent or explicit concurrency

Light-weight processesHighly scalable

Erlang Highlights: ConcurrencyErlang Highlights: Concurrency

Creating a new process using spawn

-module(ex3).-export([activity/3]).

activity(Name,Pos,Size) -> …………

Pid = spawn(ex3,activity,[Joe,75,1024])

activity(Joe,75,1024)


10 100 1,000 10,000 100,000Number of processes1

10

100

1,000

Mic

rose

con

ds/

pro

cess

erlang

java

C#

Source:Joe ArmstrongSICS

Processcreationtime

Erlang Highlights: ConcurrencyErlang Highlights: ConcurrencyProcesses communicate by asynchronous message passing

Pid ! {data,12,13} receive {start} -> ……… {stop} -> ……… {data,X,Y} -> ………end

receive {start} -> ……… {stop} -> ……… {data,X,Y} -> ………end


10 100 1,000 10,000 100,000Number of processes1

10

1,000

100,000

Mic

rose

con

ds/

mes

sage

erlang

java

C#

10,000

100

1Source:Joe ArmstrongSICS

Messagepassingtimes



Response times in theorder of milliseconds

Per-process garbage collection



Simple and consistenterror recovery

Supervision hierarchies"Program for the correct case"

Erlang Highlights: RobustnessErlang Highlights: RobustnessRobust systems can be built by layering

“Supervisors”

“Workers”



Explicit or transparent distribution

Network-awareruntime system

Erlang Highlights: DistributionErlang Highlights: Distribution

Erlang Run-Time SystemErlang Run-Time System Erlang Run-Time SystemErlang Run-Time System

B ! Msg

network

C ! Msg

Erlang Highlights: DistributionErlang Highlights: Distribution

loop() -> receive {From, {apply, M, F, A}} -> Answer = apply(M, F, A), From ! {rex, node(), Answer} loop(); _Other -> loop() end.

{rex, Node} ! {self(), {apply, M, F, A}},receive {rex, Node, What} -> Whatend






Simple Remote Procedure Call



Easily change code in a running system

Enables non-stop operationSimplifies testing



"Ports" to the outside worldbehave as Erlang processes



Erlang runs on a Virtual Machine ported to UNIX,

Windows, VxWorks, OS X, …Supports heterogeneous

networks.



Symmetric multiprocessing support. Takes full advantage

of multiple CPU architectures.

Erlang SMPErlang SMP

Erlang VM

Scheduler

run queue

non-SMP VM

Erlang VM

Scheduler #1

Scheduler #2

Scheduler #N

migration logic

run queue

run queue

run queue

SMP VM

ContentsContents


Products: Ericsson AXD301 SwitchProducts: Ericsson AXD301 Switch• A Telephony-Class, scalable (10 –A Telephony-Class, scalable (10 –

160 GBps) 160 GBps) ATM switch ATM switch

• Designed from scratch in less than 3 Designed from scratch in less than 3 yearsyears

– Proof of concept in three months– 1.5 million lines of Erlang code in the OM– 500,000 lines of C/C++ in the switch core– 13,000 lines of Java in the GUI

• AXD 301 Success factors:AXD 301 Success factors:– Competent organisation and people– Efficient process– Excellent technology (Erlang!)

Products: Ericsson AXD301 SwitchProducts: Ericsson AXD301 Switch

• Using Erlang in Complex SystemsUsing Erlang in Complex Systems– Fits very well with the incremental design method– High programmer satisfaction– Outstanding support for robustness and concurrency– Very few side-effects easier to add/change single

components– Small directed teams can achieve impressive results

• Productivity estimatesProductivity estimates– Similar line/hour programmer productivity– 4-10 fewer lines of source code (compared to C/C++, Java,

PLEX)– Similar number of faults per 1000 lines of source code

Erlang: It’s Happening!Erlang: It’s Happening!Amazon

Simple DB

Yahoo! Delicious

T-Mobile WAP, SMS, IN services

Facebook Chat channel servers

Powerset/Microsoft Key/Value store

37 SignalsBackend servers

CouchDB Distributed Robust document database

Wings 3D 3D modeller based on Nendo

YAWS Yet Another Web Server

RabbitMQ High performance enterprise messaging

Ejabberd XMPP instant messaging server

Erlang: It’s Happening!Erlang: It’s Happening!

QuestionsQuestions

www.planeterlang.org

www.trapexit.org

www.erlang-factory.com

www.erlang-consulting.com

www.erlang.org

erlang for five nines

Technology

mike willliams

erlang highlights

erlang history

erlang

factorial

time

ex1