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:

  1. Concurrency
  2. No global clock
  3. 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:

  1. CLI
  2. Registry
  3. www
  4. 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

Forward: Node, npm and SOA

By seldo

Forward: Node, npm and SOA

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