CodeMotionNotes.adoc

CodeMotion Amsterdam

How to write maintainable code?

• https://github.com/Droogans/unmaintainable-code

• How much time to invest in code refactoring?

  • Typically for new projects, assuming you are curating code well, no dedicated effort

  • Second year of the projects - start investing 10% of team effort on code refactoring

  • Increase this effort by 10% every upcoming year

• Spagetti codebase

• Lasagna Architecture - Un-necessary layering in code

• Ravioli Architecture - Microservices

• Rule of Three - code duplication

• ReadMe Contents

  • Purpose

  • Scope

  • Installation

  • API details

  • Architecture diagram

Microservices; 5 Things I wish I’d known

Monolithic issues

• Grow Fat - Codebase grows, all things slow down

• Age - Introduction of new technology becomes difficult

• Ownership -

• Economics of Scale

• Optimize for rapid aad sustainable flow of value

Value of Microservices

• Small

• Independent lifecycle

• Optimize for the problem

• Replacability

5 Patterns

Basics

A minimal Service:

• Expose a port

• Health check - 200 UP, 500 DOWN

• Stateless

• Deep Check

  • Check if service fails to connect to its dependency

Code and Builds - 1 repo 1 build Separation of config from code

Deployments

• Always deploy empty service to production

• Developers in control

  • Artifact

  • Compute

  • Resources

  • Ownership

  • Alarms

  • Configuration

Testing

How to trust your mock?

• Rely on Monitoring

• Stable API’s

• Contract testing - for internal fast moving API’s

Semantic Check:

Automated test runs against a node before it is added to LB.

Security

Atlassian GWT based solution

Operations

• Log aggregations

• Circuit Breakers

  • Response times

  • Back pressure

  • Fallback - How to handle failures?

• Request Tracing

Machine Learning for Java Developers

• Neural Networks - Every pixel of the image is considered as a separate neuron

• Activation Function

• Learning Algorithm

  • Pick up a training example (e.g. image) **

Clouds and Containers

Containers:

• Stop promoting use of openjdk:latest (promote use of right versions)

• Alternatives to Docker - Joyent Triton, CoreOS, CloudFoundry

Benefits containe brings (PODA):

• Portable

• Immutable

• Faster to build

• Lighter to distribute and run

• Availability of pre-built blocks e.g. prebuilt images

• Consistent across platforms, stages

Orchestration

What is Orchestration?

• Handles deployment

• Manages multiple containers

• Maintains targetted instance count - scaling

Optional aspects in Orchestration:

• Routing

• LB

• Service Registry

• Application Configuration

Cloud vs PaaS:

• Cloud Foundry (Open Source)