Experimental Refactoring with Go

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Experimental Refactoring

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FIND ME github.com/jelmersnoeck twitter.com/jelmersnoeck Jelmer Snoeck ABOUT ME - Tech Lead at manifold.co - Kubernetes - Terraform - Gopher since 2013 - Kubelist Contributor

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$ tree - What and why? - Techniques & Tools - Zero Downtime Refactoring - Experimental Refactoring

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Photo by Dan Gold on Unsplash Refactoring

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Code refactoring is the process of restructuring existing computer code without changing its external behavior. Wikipedia

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Refactoring is a controlled technique for improving the design of an existing code base. Martin Fowler

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Refactoring is changing things, deploying it and hoping it didn’t break anything else. Most Developers

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Photo by Emily Morter on Unsplash Why

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Photo by Alfons Morales on Unsplash Readability

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Photo by Anton Darius on Unsplash Code smells

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Code smells - Duplication - Feature envy - Large methods - Dead code - …

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Photo by Glen Carrie on Unsplash Bugs

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Product Changes Photo by Chris Lawton on Unsplash Product changes

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Product changes - New features - Modify existing features - …

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Photo by Nainoa Shizuru on Unsplash Performance + scalability

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Performance - Change of underlying package - Change of underlying algorithm - …

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Scalability - Userbase growth (100 users to 100m users) - Team growth (10 developers to 500 developers) - …

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Photo by Anoir Chafik on Unsplash

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Techniques Photo by Uriel Soberanes on Unsplash

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Techniques - Interface Abstraction - Type Aliasing (Go 1.9+) - Nil Objects - …

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Interfaces (Abstraction) Photo by Rene Böhmer on Unsplash

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Photo by Kipras Štreimikis on Unsplash Type Aliasing

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Photo by Aaron Burden on Unsplash Nil Objects

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Photo by Philip Swinburn on Unsplash Tools

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Detection Tools - CodeCov - Linting - …

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CodeCov Photo by Samuel Zeller on Unsplash

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Linting Photo by Terri Bleeker on Unsplash

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Refactoring Tools - Tests - Security that it still works - Gotests - Benchmarks - go test -bench=. - IDE - Extract methods - Find duplication easily

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gotests Photo by rawpixel on Unsplash

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go test -bench=. Photo by Ashley Baxter on Unsplash

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Photo by Mark Hessling on Unsplash

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Photo by Jyotirmoy Gupta on Unsplash

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Photo by Marcus Benedix on Unsplash

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Zero Downtime Refactoring Photo by Masaaki Komori on Unsplash

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Multi Step Changes Photo by Jake Hills on Unsplash

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Photo by Jane Carmona on Unsplash Feature Flags

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Why use Feature Toggles? - Early Access to Features - Incremental roll outs to test hypothesis - Calendar Events (Mother’s day, Launches, …) - …

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Metrics Photo by Carlos Muza on Unsplash

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Experimental Refactoring Photo by chuttersnap on Unsplash

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Photo by chuttersnap on Unsplash

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@jelmersnoeck manifold.co Thanks!

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Reading list - https://speakerdeck.com/campoy/understanding-nil - https://talks.golang.org/2016/refactor.article - https://dave.cheney.net/2013/06/30/how-to-write-benchmarks-in-go - https://github.com/cweill/gotests - https://github.com/github/scientist - https://github.com/jelmersnoeck/experiment - http://featureflags.io/ - https://github.com/launchdarkly/go-client - https://github.com/checkr/flagr