the seneca pattern at engineyard distill 2013 conference

How do You Build Big Apps?

@rjrodgersenecajs.org

Tuesday 13 August 2013

TechnicalDebt

"A good plan, violently executed now,is better than a perfect plan next week."

You Must take onTechnical Debtor You Will Die

Sometimes,it Happens

AnywayTuesday 13 August 2013

NTSC 1941 Standard:

Black+White onlySignal encodes BrightnessEach Channel gets 6Mhz

Happy Days!

Color TelevisionThree Colors: Red, Green, Blue

Each Color needs 3MhzYou only have 6Mhzand you need 9Mhz!

Technical Debt FTW

You can't Break theold Black+White TVs

We must send the old brightness signal

White Light =30% Red

59% Green11% Blue

Send White, Red and Blue

You need to embed the color signals inside

the brightness signal

Color TV circuits aremore complicated

than they should be.

How do you ReduceTechnical Debt?

Longer and more detailed

Specifications!

Better LanguagesBetter Mental Models

How did theRomans do

Long Division?Tuesday 13 August 2013

LXXII MMMDCXIIL rem XII

How did theRomans doAddition?

1. Normalize: IV → IIII2. Concatenate: IIII + XI → IIIIXI3. Sort, descending: IIIIXI → XIIIII4. Reduce: XIIIII → XV

IV + XI = ?

Subtraction?Tuesday 13 August 2013

1. Normalize: XXIV → XXIIII2. Eliminate: XXIIII - XV → XIIII - V3. Expand: XIIII - V → VIIIIIIIII - V4. Repeat 2 and 3 until no moves left5. Reduce: IIIIIIIII → IX

XXIV - XV = ?

Multiplication?Tuesday 13 August 2013

III → 3VI → 6 → 110

III × VI = ?

3 × 001 × 0 = 03 × 010 × 1 = 63 × 100 × 1 = 12 18

bit shifting

How did theRomans doDivision?

they didn't

Roman Numerals have

Technical DebtTuesday 13 August 2013

Positional Number Systems make us

SmarterTuesday 13 August 2013

Mental Modelsfor Code

ProceduralFunctional

Object-OrientedLogic

Let's Experiment

Stand up.Everybody.

Is this a car?

YES NOStay standing Sit down

And stay down!

Objects areRoman Numerals

Objects break as system complexity

growsTuesday 13 August 2013

The need for design "patterns" is telling

you somethingTuesday 13 August 2013

Procedural code tends to

SpaghettiTuesday 13 August 2013

Functional and Logic are

More PowerfulTuesday 13 August 2013

WhatHappened?

Why didn't theyWin?

Technical Debt

What do weNeed?

A BetterMental Model

Easy to LearnEasy to Scale (humans)Easy to Scale (machines)Easy to ImplementEasy to build a Mental Model

Does not have to achieveVery Large Scale

We need Modelsthat Work forHuman Brains

Why isRuby on Rails

Popular?Tuesday 13 August 2013

Opinionated==

Shared Mental ModelTuesday 13 August 2013

Ruby on RailsModel is an

Accident of HistoryTuesday 13 August 2013

Let's Design aModel!

What does a Programmer do?

Self-contained AlgorithmsProcedural Business LogicFitting it all Together

Fitting it all Together is

the Hard PartTuesday 13 August 2013

What are HumansGood At?

If a card has a vowel on one side, it must have an odd number on the other.

Which cards should you turn over to verify that the rule is followed?

If you're drinking beer, you must be 21 or over.

Which patrons should you ask for ID?

You solved the second version using

Pattern MatchingTuesday 13 August 2013

Why is Pattern Matching

Such a Win?Tuesday 13 August 2013

We are Pattern MatchersIt scales for humans and machinesWorks without needing context

Why do I Care?

We build Minimum Viable Productsfor startups.It's all about technical debt.

Lucius Annaeus Seneca

The Seneca Strategy

EmbraceMicro-Services

Lots of Little ProcessesDo one thing, and do it WellCommunicate with Messages

Pattern Match onMessages

Messages are Asynchronous Send them any way you likeUse JSON as the data model

"Send Tweet"Acted on by Tweet Service

Example

{ command:"tweet" author:"@rjrodger" status:"Distill Rocks!"}

Tweet ServiceIf I see a message with this property:

Match the Pattern!

command:"tweet"

It's Mine!I don't care how you get it to me.

And I'll ignore anything else.

The Tweet Service can be written in

Any LanguageTuesday 13 August 2013

Keep it SmallDie and restart on Errors

Report your status

Level Up ThePattern Matching

Patterns map to Actions

cmd:drivestart engine, and go!

cmd:drive, type:hoverturn on anti-gravitystart engine and go!

Example

Two Rules to make this Unique

1. More properties always wins2. Check properties alphabetically

cmd:drive

cmd:drive,type:hover

Mappingcmd: drivetype: wheelspeed: 50

cmd: drivetype: hoverspeed: 100

One More Thing

Layers

When you add a pattern:If the pattern Already Exists,

Keep the Old Action,so you can use it

inside the New Action

cmd:drivestart engine, and go!

cmd:drivecall prior actionset speed to speed

Example

Implementation

senecajs.org

Let's build stuff!

Blog Data Layer

Platform-as-a-Service

the actions are

cmd:draft, post:contentcmd:publish, post:idcmd:redact, post:idcmd:homepagecmd:comment, post:id, comment:comment

action, not abstractioneasy to learn

easy to modifyeasy to maintainself-documenting

the actions are

Data Layer

cmd:save, name:entitycmd:load, name:entitycmd:list, name:entitycmd:remove, name:entity

save some data

cmd: save, name: product,data: { name: Apple, price: 1.99 }

load some data

cmd: load, name: product,query: { name:Apple }

implement the actions

cmd:saveinsert into table name values data

cmd:loadselect * from name where query

add caching

cmd:savecall prior actionwrite into cache data

cmd:loadread data from cacheif found, return data, else call prior action

layers

cmd:savecall prior actionwrite into cache data

cmd:loadread data from cacheif found, return data, else call prior action

insert into table name values data

select * from name where query

more data layers

validationpermissionsthrottling

custom logicmultiple databases

multiple databases

cmd:save, name:sessionsave data to redis

cmd:saveinsert into table name values data

when entity is a session:

all other entities:

fine-grained controleasy to extend

easy to customizeeasy to debug - there's no magic

Micro-Services

deployerdispatchercontroller

Platform-as-a-Service

deployer

controller

dispatcher

app appapp

requestsstartstop

install

dashboard

controller actionsdash:install, app:detailssubmit cmd:install, app:details to message bus (deployer picks up)

dash:start, app:idsubmit cmd:start, app:id to message bus (dispatcher picks up)

dash:stop, app:idsubmit cmd:stop, app:id to message bus (dispatcher picks up)

deployer actionscmd:install, app:details

download app code to serverget route from app detailssubmit cmd:route, route:path, server:server to message bus (dispatcher picks up)

dispatcher actionscmd:routeadd route and server to local routing table

cmd:start, app:idstart routing requests to app

cmd:stop, app:idstop routing requests to app

controller, dispatcher, deployer are all in one app

install apps to localhostfocus on what, not how

Prototype

controller, dispatcher, deployer are separate processes

communicate via direct HTTPapps live on VMs

but ... no design changes!

Minimum ViableProduct

controller, dispatcher, deployer are many processes

communicate via a message busapps live anywhere

but ... no design changes!

Scale It

build now, scale later!easy refactoring

language independenceeasily observe and manage

How do You Build Big Apps?

Design for ManyLanguages

Design forScale

(human + machine)Tuesday 13 August 2013

Design forHuman Brains

Thank You!@rjrodger

senecajs.org

the seneca pattern at engineyard distill 2013 conference

Technology

define. distill. deploy. - korn ferry

like what you like: knowledge distill via neuron …like...

seneca growth capital vct · seneca partners limited...

cwblaunch - seneca college

paul and seneca

search to distill: pearls are everywhere but not the...

comments of the seneca nation of indians the seneca

distill sales deck

seneca - a student's seneca (oklahoma, 2006)

define. distill. deploy. - korn ferry · 2014. 8. 1. ·...

making things that work with us - distill

apv distill

seneca, what seneca? the chorus in the spanish tragedy ·...

distill letter size - university of california, berkeley

seneca sql

distill-to-label: weakly supervised instance labeling

how to distill moonshine

seneca book

gregory love and william platt - "badgeville for yammer &...

seneca college - newnham campus...