Micro Libraries FTW - Speaker Deck

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Micro Libraries FTW Piotr Solnica wroclove.rb 2014

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Who am I? Ruby and Rails developer OSS ruby hacker github.com/solnic @_solnic_

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Ruby Object Mapper github.com/rom-rb

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Agenda Big libraries vs micro libraries Micro libraries and frameworks Example micro libraries microrb.com

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Big Libraries vs Micro Libraries

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BIG LIBRARIES MICRO LIBRARIES Solving many problems Solving just one problem Big LOC Small LOC Wide interfaces Narrow interfaces High churn even after 1.0 Low churn especially after 1.0

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Rails Inﬂuence

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Ruby developers <3 Rails

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Rails has a huge impact on how we write Ruby

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Rails is in favor of huge libraries ActiveSupport and a wide adoption of monkey- patching ActiveRecord-like style - one object with a plethora of responsibilities and mixing seemingly related concerns

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Rails is great but let’s move on

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Let’s embrace Unix philosophy

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“Many UNIX programs do quite trivial things in isolation, but, combined with other programs, become general and useful tools” The UNIX Programming Environment

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Micro Libraries FTW

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Why building a micro library?

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Complex functionality that could be reused Constantly repeated design pattern A speciﬁc problem known up front

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Building frameworks based on micro libraries

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bottom-up vs top-down

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bottom-up Really great when you know exactly what you’re doing

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Does not happen very often

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top-down Really great even when you don’t know exactly what you’re doing

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Happens almost all the time

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Unfortunately top-down approach can be misleading

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DSL + core domain logic == disaster

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Frameworks should provide high-level interfaces that are built on top of lower level micro libraries

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Challenges

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Dealing with many dependencies is hard

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rubygems + bundler = slow “meta-gems” PANIC when seeing lots of gems being installed

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Dependency Hell

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2 gems depending on diﬀerent versions of another gem == HELL

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Version conﬂicts between frameworks are the biggest challenge

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Semantic Versioning

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Be responsible!

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Changelogs

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Tools can help!

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ruby-toolbox.com lots of information about gems gemnasium.com detailed information about dependencies of gems

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Example micro libraries

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github.com/dkubb/equalizer

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require "equalizer"! ! class GeoLocation! include Equalizer.new(:lat, :lng)! ! attr_reader :lat, :lng! ! def initialize(attributes)! @lat, @lng = attributes.values_at(:lat, :lng)! end! end! ! loc1 = GeoLocation.new(:lat => 123, :lng => 321)! loc2 = GeoLocation.new(:lat => 123, :lng => 321)! ! loc1 == loc2 # true! ! loc1.inspect! => #

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github.com/mbj/anima

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equalizer + anima

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require "anima"! ! class GeoLocation! include Anima.new(:lat, :lng)! end! ! loc1 = GeoLocation.new(:lat => 123, :lng => 321)! loc2 = GeoLocation.new(:lat => 123, :lng => 321)! ! loc1 == loc2! # => true

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virtus + equalizer

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require "virtus"! ! class GeoLocation! include Virtus.value_object! ! values do! attribute :lat, Float! attribute :lng, Float! end! end! ! loc1 = GeoLocation.new(:lat => "123", :lng => "321")! loc2 = GeoLocation.new(:lat => "123", :lng => "321")! ! loc1 == loc2! # => true

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How about a framework?

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Ruby Object Mapper github.com/rom-rb/rom

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morpher github.com/mbj/morpher

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rom + morpher

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module ROM! class Mapper! ! # Abstract loader class! #! # @private! class Loader! ! # some stuff is here! ! # @api public! def call(tuple)! transformer.call(tuple)! end! ! end # Loader! ! end # Mapper! end # ROM This is morpher’s transformer and it takes care of everything

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virtus 2.0 = anima + morpher

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microrb.com

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Gather libraries that meet speciﬁc criteria Make it easy to ﬁnd the right tool for the job Help in connecting maintainers and contributors Promote style of development that adheres to the unix philosophy Promote frameworks that are built on top of micro libraries

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Thank You! <3<3<3