Forward 4, 2016-02-10

This is not a talk about code

This is about architecture

Service Oriented Architecture

What is it
Why use it
Why do it in node?
How to do it properly
How npm uses SOA

Confession time

I rewrote this whole talk yesterday.

Part 1: what is SOA?

SOAs are a distributed system

Distributed systems feature:

Concurrency
No global clock
Independent components

What about microservices?

Part 2: advantages of SOA

technical
organizational

Resource efficiency

Cost efficiency

specialization
scalability
tunability

Robustness

Never gonna give you up,

never gonna take you down.

Robustness

0.01^100 = 0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001%

100 boxes, 1% chance of failure

Chance of being completely down:

0.01*100 = 100%

Chance of being slightly down:

Debuggability

Organizational advantages

Conway's Law in reverse

Simpler systems are simpler

Smaller systems allow for smaller teams

Smaller teams are better teams

Big teams are hard, so don't have any.

Part 3: why node is great at SOA

#1: Node is inherently good

at writing web services

#2: small modules make for efficient microservices

#3: node and npm make shared logic easier

and now, a shameless product plug

Share code within your company using npm On-Site, or npm Organizations

Part 4: best practices for SOA in node

application-level
architectural
operational

Application level

Isolation

Consistency

access-cache
billing-api
docs
frontdoor
partners
registry-relational
user-acl
validate&store
www

downloads-api
fastly-purge
login-cache
public skimdb
search
tarball follower
credentials follower
slackboard

npm's services

Consistent error handling

crash on error
restart on crash
monitor restarts

Shared logic

The less unique code, the faster the fix.

Architectural

Asynchronous operations will save your life

Fail safely and softly

Expect flaky networks
Degrade gracefully
Recover automatically

Race conditions

conditions. So race many

Operational

Configuration

one source of truth
configure at deploy

Deployment

automate everything
use "canary" servers

Handle cold starts

Can the service deploy if it's down?
Will creep up on you slowly

Metrics

Capture every request
- source
- frequency
- size
Log every response
- type
- speed
- size
Log every event

Monitoring & Alerting

Dashboards: not just for show
Alert on out-of-range metrics

Part 5: npm as SOA

A case study

What is npm?

4 things:

CLI
Registry
www
On-Site

Fun fact

One thing

One big, complicated thing

The CLI

The Registry

More registry

Followers

www

npm On-Site

Service re-use

Takeaways

SOA is neat
Node is good at SOA
You can be good at SOA
npm is pretty neat, too

Thank you!

laurie@npmjs.com

Twitter: @seldo