Build and maintain large ruby applications - LA Ruby Oct meetup

build and maintain large Ruby
applications
Enrico Teotti - @agenteo - http://teotti.com
enrico.teotti@gmail.com
starting shortly

build and maintain large Ruby
applications
http://www.slideshare.net/agenteo/build-and-maintain-large-ruby-applications-ruby-conf-australia-2016

crowbar.rb spec.description = ”Builds and maintains large Ruby apps”

–Any Java developer always ;-)
“Ruby is a toy language.”

automated
testing
team
diligence
local Ruby
gems

Ruby ﬁles in a project are like ingredients in a recipe

yeasthoney
salt
milk ﬂourwaterlard
sugar
arugula
squacqueroneprosciutto

piadina
yeasthoney
salt
sugar
arugula

piadina
the curse of
knowledge
yeasthoney
salt
sugar
arugula

6 months later
– The law of continuing change (1974) Lehman, M
“Any software system used in the real-world must change or
become less and less useful in that environment.”
– The law of increasing complexity (1974) Lehman, M
“As a program evolves, it becomes more complex, and extra
resources are needed to preserve and simplify its structure.”

biscuits
mozzarella
sunﬂower oil
carrots
eggs
tomato puree
basil
mascarpone
coffee
cacao
yeasthoney
salt
sugar
arugula
oregano

sunﬂower oil
carrots
gs
tomato puree
basil
mascarpone
coffee
cacao
yeasthoney
salt
sugar
arugula
oregano
piadina
pizza margherita
tiramisu
carrot cake

white ingredients
green ingredients
red ingredients
yellowish ingredients
orange ingredients
dark ingredients

white ingredients
green ingredients
classes grouped
by design pattern
ls -l app/
controllers
helpers
models
presenters
services
serializers
strategies
utils
views
http://teotti.com/application-directories-named-as-architectural-patterns-antipattern/

piadina
pizza margherita
tiramisu
carrot cake

# lib/blog/after_publish.rb
module Blog
class AfterPublish
private
def subscribe_blogger_to_promotion
Promotions::Submission.new
end
end
end
# lib/promotions/new_member.rb
module Promotions
class Submission
private
def fetch_member(id)
# lib/membership/finder.rb
Membership::Finder.new(id)
end
end
end
promotionsblog membership
namespaces
context context

promotions
name
ﬁnder
blog membership
main Ruby application
1 year
lib

promotions
room
decorator
name
ﬁnder
blog membershiprecipes
comments
lib
3 years

piadina worktop
tiramisu worktop
shared worktop
carrot cake worktop
pizza worktop

A
piadina gem

Apiadina gem
pizza gem
C
shared
ingredients
gem
B

Apiadina gem
pizza gem
C
shared
ingredients
gem
B
spec.add_dependency "shared_ingredients"
# local_gems/pizza/pizza.gemspec

Apiadina gem
pizza gem
C
shared
ingredients
gem
B
spec.add_dependency "shared_ingredients"
# local_gems/piadina/piadina.gemspec

piadina gem
pizza gem
C
shared
ingredients
gem
B
desserts gem
D
A

piadina gem
pizza gem
C
shared
ingredients
gem
B
desserts gem
D
A
E
calzone gem
pizza dough gem
F
Conway’s Law
“organizations which design systems … are constrained to produce designs which
are copies of the communication structures of these organizations"

piadina gem
pizza gem
shared
ingredients
gem
desserts gem
D
A
calzone gem
pizza dough gem
F
B
E
C

http://teotti.com/create-dependency-structures-with-local-ruby-gems/
code & examples

A
C
D
B
E
your health plan
drug information
claims platform
product
information
membership
gem
gem
gem
gem
gem
dependency
Sinatra / Rails / Hanami

!"" Gemfile
!"" Gemfile.lock
!"" local_gems
!"" run.rb
#"" spec
ruby script that
triggers entry point
gem’s behaviour
require 'health_plan'
subscriber_id = 'ASE123456789'
aggregated_drug_information = HealthPlan::Aggregator.new(subscriber_id)
puts aggregated_drug_information.details

!"" Gemfile
!"" Gemfile.lock
!"" local_gems
!"" run.rb
#"" spec
path 'local_gems' do
gem 'health_plan'
end
source 'https://rubygems.org'
group :test do
gem 'rspec'
end
bundler’s Gemfile uses
a path directive to find
local gems

!"" Gemfile
!"" Gemfile.lock
!"" local_gems
!"" run.rb
#"" spec
bundler’s Gemfile uses
a path directive to find
local gems
path 'local_gems' do
gem 'health_plan'
end
group :test do
gem 'rspec'
end

!"" Gemfile
!"" Gemfile.lock
!"" local_gems
!"" run.rb
#"" spec
directory where your local gems are
$ cd local_gems
$ bundle gem health_plan
create health_plan/Gemfile
create health_plan/Rakefile
create health_plan/LICENSE.txt
create health_plan/README.md
create health_plan/.gitignore
create health_plan/health_plan.gemspec
create health_plan/lib/health_plan.rb
create health_plan/lib/health_plan/version.rb
Initializing git repo in /Users/me/code/lab/gem-dependency-structure/local_gems/health_plan
$ rm -Rf health_plan/.git*
bundle gem can create gems

# local_gems/health_plan/health_plan.gemspec
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'health_plan/version'
Gem::Specification.new do |spec|
spec.name = "health_plan"
spec.version = HealthPlan::VERSION
spec.authors = ["Enrico Teotti"]
spec.email = ["enrico.teotti@gmail.com"]
spec.summary = %q{Write a short summary. Required.}
spec.description = %q{Write a longer description. Optional.}
spec.homepage = ""
spec.license = "MIT"
spec.files = `git ls-files -z`.split("x0")
spec.executables = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
spec.test_files = spec.files.grep(%r{^(test|spec|features)/})
spec.require_paths = ["lib"]
spec.add_development_dependency "bundler", "~> 1.7"
spec.add_development_dependency "rake", "~> 10.0"
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec
spec.add_development_dependency "rspec", "3.4.0"
end
your health plan

# local_gems/health_plan/spec/health_plan/aggregator_spec.rb
require 'spec_helper'
describe HealthPlan::Aggregator do
describe "#details" do
it "should not throw exceptions" do
aggregator = HealthPlan::Aggregator.new(12345)
expect(aggregator.details).to eq({ name: 'The full package plan'})
end
end
end
your health plan
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec

# local_gems/health_plan/lib/health_plan/aggregator.rb
module HealthPlan
class Aggregator
def initialize(id)
@subscriber_id = id
end
def details
{ name: 'The full package plan'}
end
end
end
# local_gems/health_plan/lib/health_plan.rb
require "health_plan/version"
require "health_plan/aggregator"
module HealthPlan
end
gem entry point
your health plan
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec

!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ !"" drug_information
$ #"" health_plan
!"" run.rb
#"" spec
your health plan
drug information
$ cd local_gems
$ bundle gem drug_information
create drug_information/Gemfile
create drug_information/Rakefile
create drug_information/LICENSE.txt
create drug_information/README.md
create drug_information/.gitignore
create drug_information/drug_information.gemspec
create drug_information/lib/drug_information.rb
create drug_information/lib/drug_information/version.rb
drug information

# local_gems/health_plan/spec/health_plan/aggregator_spec.rb
require 'spec_helper'
describe HealthPlan::Aggregator do
describe "#details" do
let(:fetched_drugs) { 'something' }
before do
fetcher_double = double('DrugInformation::Fetcher', details: fetched_drugs)
allow(DrugInformation::Fetcher).to receive(:new).and_return(fetcher_double)
end
it "should not throw exceptions" do
aggregator = HealthPlan::Aggregator.new(12345)
expect(aggregator.details).to eq({ name: 'The full package plan’,
drugs: fetched_drugs })
end
end
end
your health plan
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec

your health plan
lib = File.expand_path('../lib', __FILE__)
$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
require 'health_plan/version'
Gem::Specification.new do |spec|
spec.name = "health_plan"
spec.version = HealthPlan::VERSION
spec.authors = ["Enrico Teotti"]
spec.email = ["enrico.teotti@gmail.com"]
spec.summary = %q{Write a short summary. Required.}
spec.description = %q{Write a longer description. Optional.}
spec.homepage = ""
spec.license = "MIT"
spec.files = `git ls-files -z`.split("x0")
spec.executables = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
spec.test_files = spec.files.grep(%r{^(test|spec|features)/})
spec.require_paths = ["lib"]
spec.add_development_dependency "bundler", "~> 1.7"
spec.add_development_dependency "rake", "~> 10.0"
spec.add_development_dependency "rspec", "3.4.0"
spec.add_dependency "drug_information"
end
# local_gems/health_plan/health_plan.gemspec
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec

your health plan
# local_gems/health_plan/Gemfile
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec
path '..'
‘..’ represents the parent directory

# local_gems/health_plan/lib/health_plan/aggregator.rb
module HealthPlan
class Aggregator
def initialize(id)
@subscriber_id = id
end
def details
fetched_drug_info = DrugInformation::Fetcher.new(@subscriber_id)
{ name: 'The full package plan', drugs: fetched_drug_info.details }
end
end
end
# local_gems/health_plan/lib/health_plan.rb
require "health_plan/version"
require "health_plan/aggregator"
require "drug_information"
module HealthPlan
end
gem entry point
your health plan
!"" Gemfile
!"" Gemfile.lock
!"" local_gems
$ #"" health_plan
!"" run.rb
#"" spec
require dependent gem

A
C
D
B
E
unit tested
unit tested
unit testedunit tested
unit tested
acceptance tests

A
C
B
loaded in memory, deamon or webserver
unit tested
unit tested
not unit tested
http://teotti.com/create-dependency-structures-with-local-ruby-gems#gotcha-ﬂaky-bugs-caused-by-missing-requirement-statements

A
C
D
B
E
Jurassic Ruby application
developer
CEO
head of product
QA “resource”
QA “resource”

A
C
D
B
E
F
H
I L
membership
payment API
payment
platform
bank
transaction
credit card
transaction
your health plan
API
drug information
claims platform
product
information
membership

A
C
D
B
E
F
H
I L
I ﬁnd your use of
Gems disturbing
Do I really look like
a guy with a plan?
*nods then
deletes your
Gem*

http://teotti.com/rails-service-oriented-architecture-alternative-with-components/
to be continued…
premature use of SOA

your health
plan API
drug
information
claims
platform
product
information
membership
membership
payment
API
payment
platform
bank
transaction
credit card
transaction

deploy parts of a monolith
http://teotti.com/deploy-parts-of-a-ruby-on-rails-application/

monolithic Ruby application
DB

editorial admin ui
persistence
site search
componentized Ruby application
public content ui
shared ui
DB

deploy@adminServer $ RUNNING_MODE=admin puma

editorial admin ui
persistence
site search
Rails application
public content ui
shared ui
DB

deploy@publicServer $ RUNNING_MODE=public puma
http://teotti.com/deploy-parts-of-a-ruby-on-rails-application/

editorial admin ui
persistence
site search
Rails application
public content ui
shared ui
DB
legacy
migration
AWS
SQS
massage and
transform content
legacy system
pull legacy
content

http://cbra.info

automated
testing
team
diligence
local Ruby
gems
team
in a
ﬁxed
mindset

Build and maintain large ruby applications - LA Ruby Oct meetup

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