REAL WORLD LESSONS ON THE ANTI-PATTERNS OF NODE.JS

@Ben_Hall

Ben@BenHall .me.uk

Blog.BenHall .me.uk

MY BATTLE SCARS OF NODE.JS

@Ben_Hall

Ben@BenHall .me.uk

Blog.BenHall .me.uk

MY LIFE, MY STORY… BY BEN HALL.

PUBLISHER TBC

$ whoami

Ocelot Uproar

@Ben_Hall

Tea boy > Tester > Developer > Freelancer > Tea boy?

Agenda

• Modules + NPM

• Project Structure

• Async

• Error Handling

• Testing

• Debugging

• Production

Disclaimer

Examples are not a refl ection on the developer/team/company. Based on

problems I ’ve caused myself or struggled with. JavaScript is very

subjective…blah blah blah… If you’re doing it r ight, then *amazing*! I ’m

not.

Love, Ben x

WHO CARES ABOUT CLEAN CODE IF THERE ARE NO SALES?

Prototypes

MODULES + NPM

Package.json + NPMWonderful!

Look at NuGet, GoDep, Bundler

AngularJs 1.2 => 1.3

1. "dependenc ies" : {

2. "angu lar" : "^1.2 .16”

3. }

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Angular 1.2 => 1.3

> angular.element(document)

[#document]

> angular.element(document)

TypeError: undefi ned is not a function

Lock Down Dependencies

Randomly breaking bui lds and deployments wil l occur

otherwise

$ npm shrinkwrap

Lock down dependencies to what’s running local ly

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Hard code versions in package.json

1. "dependencies": {

2. "angular": “1.2.23”

3. }

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$ npm outdated

$ npm install

Downloading the internet on each deployment can be

slow

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$ npm install --production

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$ npm install -g

Genera l ly promoted by test f rameworks . Genera l ly ends up

not be ing in package. j son. Genera l ly broke my deployment .

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“HELPERS” & PROJECT STRUCTURE

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Libs/<Context>/<Task>.jsLibs/auth/users/create.js

Why not an NPM?

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ASYNC

Because J avaSc r ip t

Promises

Promises… Promises… Never break your promises .

Personal ly , I never make promises .

http://domenic.me/2012/10/14/youre-missing-the-point-of-promises/

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Not part of the Node

Makes integration more diffi cult. Makes swapping

code in / out more painful.

Callbacks

So good it ’s got it ’s own website cal lbackhel l .com

“The goal i sn ’ t about removing levels o f indentat ion but rather wr i t ing modular

code that i s easy to reason about”

Strongloop Blog

http://strongloop.com/strongblog/node-js-callback-hell-promises-generators/

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Loops + Async Callbacks��

Loops + Async Callbacks��

“You can't get into callback hell if you don't go there.”

Isaac Schlueter

Generators are coming!

See Node >=0.11.2

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http://blog.alexmaccaw.com/how-yield-will-transform-node

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http://blog.alexmaccaw.com/how-yield-will-transform-node

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ERROR HANDLING

Wasn’t great from the start

Sti l l not great

Try {} Catch {}��

Try {} Catch {}��

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Domains haven’t really worked

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Event Driven Errors��

Event Driven Errors��

Returning String as Error��

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Async Flow Control

Zones are coming!

See Node >=0.11.2

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https://raw.githubusercontent.com/strongloop/zone/master/showcase/curl/curl-zone.js

Generators + Error Handling

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TESTING

Callback Hell v2

I t ’s even worse the second time around…

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DEBUGGING

Yay! Console.log

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Writing onto a fi le onto a production box is painful to debug

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http://bigsnarf.files.wordpress.com/2014/02/screen-shot-2014-02-27-at-1-42-54-pm.png

node-bunyan��

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https://papertrailapp.com/

@Stack72’s talk or speak with @gblock

Fr iday @ 14.20

BUILDING A MONITORING INFRASTRUCTURE WITH PUPPET

DEPLOYMENT

https://groups.google.com/forum/#!topic/nodejs/NQkz3-BEwYw

Binding to Port 80��

https://groups.google.com/forum/#!topic/nodejs/NQkz3-BEwYw

Binding to Port 80Answer: sudo node app.js

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Nginx handles SSL Termination, Load Balancing, Cache Headers

Let Node be Node

http://blog.benhall.me.uk/2011/12/using-nginx-to-server-static-files-instead-of-node-js/

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http://blog.benhall.me.uk/2011/12/using-nginx-to-server-static-files-instead-of-node-js/

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Docker

Digital Ocean Droplet

Nginx bound to port 80

Node.js bound to 3000

ElasticSearch Container

Node.js bound to 3000

HTTP Request ��

AND FINALLY

Node is *Amazing*

Let’s you get away with a lot without hurting too much

Async and Errors are the biggest issue. Everything

else is easier once they’re solved.

@Ben_Hal l

Ben@BenHal l .me.uk

Jo inScrapbook.com