Staying Railsywhile scaling complexity

Rails in the Enterprise

David Williams@metakube

Of all the terms I hate with a passion, “professional” would probably rank

above “enterprise” and just below “potty mouth”.

–@dhh in 2009

What does

ENTERPRISEmean?

XML

SOAP

EDI

BPEL ABAP/4

COBOL Work

flow

automationvisibilitycompliance

it comes down to

$

But we’re software people. Start talking tech.

–y’all, just now

COMPLEXITY

What does

COMPLEXITYmean?

languagesstandard user rolescontrollers database tablespermissionslines of codeAPI calls / dayrows in biggest tablespend through system

514

166183

157758k

>100k3m

$5.6b

InternationalizationLocalization

XSS protectionSingle sign-onData securityExtensibility

CustomizationAPI integration

S*@P

mixin

sco

mple

x queries

state

machin

es

RULEm

etaco

de

mixin

sco

mple

x queries

state

machin

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RULEm

etaco

de

Aspect Oriented Programming

Cross Cutting Concerns

Decorator Pattern

Adapter Pattern

Pointcuts

Separation of Concerns

Multiple Inheritance

Mixins

class RequisitionHeader

< ActiveRecord::Base

has_custom_fields

acts_as_revisionable

securable_by_account

api_in

api_out

end

class RequisitionHeader

< ActiveRecord::Base

has_custom_fields

acts_as_revisionable

securable_by_account

api_in

api_out

end

Let’s talk about these

mixin

sco

mple

x queries

state

machin

es

RULESm

etaco

de

I ♥ruby

class Api::DepartmentsController < Api::BaseController api_scaffold :department

end

Coupa::Application.routes.draw do namespace :api do resources :departments endend

class Department < ActiveRecord::Base

api_in [:name, :active], [], {:keys => ["id", "name"]}

api_out [:name, :active]

end

class Department < ActiveRecord::Base

api_in [:name, :active], [], {:keys => ["id", "name"]}

api_out [:name, :active]

end

(lack of) associations

class Department < ActiveRecord::Base

api_in [:name, :active], [], {:keys => ["id", "name"]}

api_out [:name, :active]

end

(lack of) associations

class Api::BaseController < AppController

def self.api_scaffold(model_id, options={})options.assert_valid_keys(:class_name, :scope, :user_scope, :validate_if, :before_save)singular_name = model_id.to_sclass_name = options[:class_name] || singular_name.camelizemodel_class = class_name.constantize

[way more code than I can fit]self.module_eval(overlay_methods)

end

end

APIs and...

bulk loaderscustom fieldssearchable table viewsbudgetingapproval workflowsrevision trackingreportingnotificationscachingand more...

APIs and...

mixin

sco

mple

x queries

state

machin

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RULEm

etaco

de

We use AASM*Monkeypatched for transactional error handling, and for the event transitions to work like they used to.

*

class RequisitionHeader < ActiveRecord::Basestate :pending_buyer_action, :enter => Proc.new { |r|

Notifier.req_requires_action(r) }

state :pending_approval, :after_enter => Proc.new { |r|

ApprovalNotify.next_approver(r)}

state :ordered, :enter => Proc.new { |r|

OrderHeader.create_from_req(r) }end

class RequisitionHeader < ActiveRecord::Basestate :pending_buyer_action, :enter => Proc.new { |r|

Notifier.req_requires_action(r) }

state :pending_approval, :after_enter => Proc.new { |r|

ApprovalNotify.next_approver(r) }

state :ordered, :enter => Proc.new { |r|

OrderHeader.create_from_req(r) }end

class RequisitionHeader < ActiveRecord::Base event :submit_for_approval do

transitions :to => :pending_approval,

:from => [:draft, :cart], :guard => :approvable?

transitions :to => :pending_buyer_action,

:from => [:draft, :cart],

:guard => :submittable? endend

class RequisitionHeader < ActiveRecord::Base event :submit_for_approval do

transitions :to => :pending_approval,

:from => [:draft, :cart], :guard => :approvable?

transitions :to => :pending_buyer_action,

:from => [:draft, :cart],

:guard => :submittable? endend

class RequisitionHeader < ActiveRecord::Base event :submit_for_approval do

transitions :to => :pending_approval,

:from => [:draft, :cart], :guard => :approvable?

transitions :to => :pending_buyer_action,

:from => [:draft, :cart],

:guard => :submittable? endend

What’s the point?

class RequisitionHeader < ActiveRecord::Base validates_presence_of :ship_to_address,

:if => Proc.new { |requisition_header|

requisition_header.status && !%w(draft cart pending_buyer_action). include?(requisition_header.status)

}

end

class RequisitionHeader < ActiveRecord::Base def editable?

user = User.current_user case self.status when 'pending_approval' approvable_by? && user && user.authorized?('approver', 'edit') when 'cart', 'draft' user == self.requested_by || user == self.created_by when 'pending_buyer_action' user && user.authorized?('buying', 'edit') else false end endend

Yawn. Show me a hack.

–y’all, just now

module ActiveSupport::Inflector def humanize_with_translation(underscored_word) begin (I18n.translate!("statuses.#{underscored_word}",

:default => :"activerecord.models.#{underscored_word}", :count => 1) unless underscored_word.blank?) || ''

rescue I18n::MissingTranslationData => e humanize_without_translation(underscored_word) end end alias_method_chain :humanize, :translationend

I18n loose end tying: Ugly but useful

mixin

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RULEm

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IF YOU TREAT YOUR DB AS DUMB

HOW CAN IT LOVE YOU?

IF YOU TREAT YOUR DB AS DUMB

HOW CAN IT LOVE YOU?

SELECT distinct suppliers.id FROM suppliers JOIN supplier_items ON supplier_items.supplier_id = suppliers.id LEFT OUTER JOIN catalogs ON catalogs.id = supplier_items.catalog_id LEFT OUTER JOIN contracts ON contracts.id = supplier_items.contract_id LEFT OUTER JOIN business_group_assignments ON (business_group_assignments.securable_id = contracts.id AND business_group_assignments.securable_type = 'Contract') STRAIGHT_JOIN items ON (items.id = supplier_items.item_id AND items.active = 1 AND (items.connect_item_id IS NULL OR items.imported_from_connect = 1)) WHERE ( suppliers.status = 'active' AND (supplier_items.catalog_id IS NULL OR ( catalogs.status = 'accepted' AND (catalogs.start_date IS NULL OR '2011-11-15 18:30:00' >= catalogs.start_date) AND (catalogs.end_date IS NULL OR '2011-11-15 18:30:00' < catalogs.end_date) )) AND (supplier_items.contract_id IS NULL OR (contracts.status = 'published' AND business_group_assignments.business_group_id in (3,2,1) AND contracts.start_date <= '2011-11-15 18:30:00' AND (contracts.end_date IS NULL OR contracts.end_date > '2011-11-15 18:30:00') ))

SELECT distinct suppliers.id FROM suppliers JOIN supplier_items ON supplier_items.supplier_id = suppliers.id LEFT OUTER JOIN catalogs ON catalogs.id = supplier_items.catalog_id LEFT OUTER JOIN contracts ON contracts.id = supplier_items.contract_id LEFT OUTER JOIN business_group_assignments ON (business_group_assignments.securable_id = contracts.id AND business_group_assignments.securable_type = 'Contract') STRAIGHT_JOIN items ON (items.id = supplier_items.item_id AND items.active = 1 AND (items.connect_item_id IS NULL OR items.imported_from_connect = 1)) WHERE ( suppliers.status = 'active' AND (supplier_items.catalog_id IS NULL OR ( catalogs.status = 'accepted' AND (catalogs.start_date IS NULL OR '2011-11-15 18:30:00' >= catalogs.start_date) AND (catalogs.end_date IS NULL OR '2011-11-15 18:30:00' < catalogs.end_date) )) AND (supplier_items.contract_id IS NULL OR (contracts.status = 'published' AND business_group_assignments.business_group_id in (3,2,1) AND contracts.start_date <= '2011-11-15 18:30:00' AND (contracts.end_date IS NULL OR contracts.end_date > '2011-11-15 18:30:00') ))Not very Rails

y

So let’s step back a moment and talk about a common problem...

Displaying paginated search results

What you’re querying on doesn’t always match what you’re

displaying

Suppliers

Contacts

Addresses

Commodities

Users

Countries

Roles Permissions

And this is a simple one...

Suppliers

Contacts

Addresses

Commodities

Users

Countries

Roles Permissions

And this is a simple one...

Shipping Terms

Payment Terms

Phone Numbers

Online Stores

Parent Suppliers

outer join != :include

.joins(begin options[:include].deep_exec{|c|

c.to_sym.send(:outer) }

rescue []end)

Depends on Ernie Miller’s awesome Metawhere / Squeel

Depends on a Ruby monkeypatch

Wow, that’s nasty. Why would you do that?

–y’all, just now

30% improvement in common cases

30% improvement in common cases

90% improvement in some nasty cases

30% improvement in common cases

90% improvement in some nasty cases

YMMV

MySQL doesn’t ♥ sorting

Narrow your SELECT clauses

.paginate({:select => 'SQL_CALC_FOUND_ROWS

DISTINCT #{table}.id', :per_page => 20, :page => options[:page] })

.paginate({:select => 'SQL_CALC_FOUND_ROWS

DISTINCT #{table}.id', :per_page => 20, :page => options[:page] })

MySQL count query avoidance hack. YMMV.

.paginate({:select => 'SQL_CALC_FOUND_ROWS

DISTINCT #{table}.id', :per_page => 20, :page => options[:page] })

MySQL count query avoidance hack. YMMV.

[Then query just the rows you want]

class Array def deep_exec(&blk) result = [] each do |e| if e.respond_to?(:deep_exec) result << e.deep_exec(&blk) else result << yield(e) end end result endend

Like deep_clone? Try deep_exec.

class Array def deep_exec(&blk) result = [] each do |e| if e.respond_to?(:deep_exec) result << e.deep_exec(&blk) else result << yield(e) end end result endend

class Hash def deep_exec(&blk) result = {} each do |k,v| result[yield k] =

if v.respond_to?(:deep_exec) v.deep_exec(&blk) else yield v end

end result endend

Like deep_clone? Try deep_exec.

Totally out of time...

We’re Hiring!(I know, total surprise.)

Photo CreditsUsed under Creative Commons from typedow

Used under Creative Commons from gaymerbear

http://popartmachine.com/blog/pop-art-based-on-hawaiian-shirt-pattern.html

Used under Creative Commons from Mandy_Jansen

Used under Creative Commons from casey.marshall