The document discusses refactoring a monolithic Rails application into a service-oriented architecture (SOA). It describes separating the application into multiple services based on functionality (e.g. qualification logic, delivery logic). This is done incrementally using a "strangler fig" approach of creating new services alongside the existing monolithic code. Tests are used to define the behavior of the new services. Data validation rules are also separated out into a scrubbing service. The approach aims to separate responsibilities, operate services asynchronously, and make incremental changes to transition from a monolithic to microservices architecture.

1. Refactoring Your
Monolithic Rails App
To A SOA:
Risks and Rewards
Saturday, March 19, 2011

2. Chris Wyckoff
Alliance Health Networks
cbwyckoff@gmail.com
@cwyckoff
Saturday, March 19, 2011

3. The Birth Of A Monolithic Rails App:
A Simple Survey Engine
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5. Saturday, March 19, 2011

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9. Saturday, March 19, 2011

10. Pretty Simple App, huh?
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11. “But we need to remarket all those emails.”
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12. Saturday, March 19, 2011

13. “We need more complex surveys.”
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14. Saturday, March 19, 2011

15. “Now we need an admin. And where’s our reporting?”
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16. Saturday, March 19, 2011

17. “Some clients need SOAP deliveries.”
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18. Saturday, March 19, 2011

19. And so on for 4 years.
Until...
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20. “What’s wrong with the site guys?”
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21. 1. Slow
2. Buggy
3. New Features Take Forever To Implement
4. Deploys Are A Nightmare
5. Tons Of Dependencies
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22. We Needed To Go From This...
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23. Monolithic Rails
App Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

24. To This...
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25. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Operational Reporting
Data Stores
Survey Budget
Admin
Engine Service
Saturday, March 19, 2011

26. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Operational Reporting
Data Stores
Survey Budget
Admin
Engine Service
Saturday, March 19, 2011

27. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Operational Reporting
Data Stores
Survey Budget
Admin
Engine Service
Saturday, March 19, 2011

28. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Operational Reporting
Data Stores
Survey Budget
Admin
Engine Service
Saturday, March 19, 2011

29. But How?
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30. The Strangler Approach
Good Code
Bad Code
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31. 3 Drivers To Our ‘Strangler’ Approach:
1. Separate Responsibilities
2. Operate Asynchronously
3. Make Incremental Changes
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32. 1. Separate Responsibilities
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33. Consolidate Like Functionality
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34. Qualification Monolithic Rails
Logic App Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

35. Qualification
Monolithic Rails
Logic App Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

36. Qualification
Monolithic Rails
App Logic Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

37. Monolithic Rails
Qualification
App Company
Logic Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

38. Monolithic Rails
App Delivery Logic
Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

39. Monolithic Rails
Delivery Logic App Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

40. Legacy Tests As Behavior Scaffolding
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41. describe Contact do
describe "#validate" do
it "requires 10 digit phone numbers" do
...
end
it "rejects blank phone numbers" do
...
end
it "rejects areacodes that start with 0 or 1" do
...
end
it "requires 5 digit zip" do
...
end
it "rejects invalidly formatted emails" do
...
end
it "rejects blank emails" do
...
end
it "rejects emails with bad words" do
...
end
...
end
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42. describe Contact do
describe "#validate" do
it "requires 10 digit phone numbers" do
Phone
...
end
it "rejects blank phone numbers" do
...
end
it "rejects areacodes that start with 0 or 1" do
...
end
it "requires 5 digit zip" do
...
end
it "rejects invalidly formatted emails" do
...
end
it "rejects blank emails" do
...
end
it "rejects emails with bad words" do
...
end
...
end
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43. describe Contact do
describe "#validate" do
it "requires 10 digit phone numbers" do
...
end
it "rejects blank phone numbers" do
...
end
it "rejects areacodes that start with 0 or 1" do
...
end
it "requires 5 digit zip" do
...
Zip
end
it "rejects invalidly formatted emails" do
...
end
it "rejects blank emails" do
...
end
it "rejects emails with bad words" do
...
end
...
end
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44. describe Contact do
describe "#validate" do
it "requires 10 digit phone numbers" do
...
end
it "rejects blank phone numbers" do
...
end
it "rejects areacodes that start with 0 or 1" do
...
end
it "requires 5 digit zip" do
...
end
it "rejects invalidly formatted emails" do
...
Email
end
it "rejects blank emails" do
...
end
it "rejects emails with bad words" do
...
end
...
end
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45. describe Phone do
describe "#is_satisfied_by?" do
it "returns false if the number is not 10 digits long" do
...
end
it "returns false if number matches invalid number list" do
...
end
it "returns true if area code is valid" do
...
end
...
end
end
describe Zip do
describe "#is_satisfied_by" do
it "returns false if zip is not 5 digits" do
...
end
it "returns false if zip does not exist in postal_codes database table" do
...
end
...
end
end
Saturday, March 19, 2011

46. describe Contact do
describe "#validate" do
it "requires 10 digit phone numbers" do
...
end
it "rejects blank phone numbers" do
...
end
it "rejects areacodes that start with 0 or 1" do
...
end
it "requires 5 digit zip" do
...
end
it "rejects invalidly formatted emails" do
...
end
it "rejects blank emails" do
...
end
it "rejects emails with bad words" do
...
end
...
end
Saturday, March 19, 2011

47. scrubber = Scrubber.configure do |s|
s.scrub(:first_name).as(:invalid).if(:blank)
s.scrub(:last_name).as(:invalid).if(:blank)
s.scrub(:email).as(:invalid).if(:blank)
s.scrub(:phone).as(:invalid).if(:blank)
s.scrub(:first_name).as(:invalid).unless(:kid_friendly)
s.scrub(:last_name).as(:invalid).unless(:kid_friendly)
s.scrub(:email).as(:invalid).unless(:kid_friendly)
s.scrub(:country).as(:filtered).if {|lead| lead.contact.country == 'Other'}.and_warn
("Only requests from the United States can be accepted at this time")
s.scrub_with(:email).as(:filtered)
s.scrub_with(:education_level).as(:filtered)
s.scrub_with(:duplicate).as(:filtered)
end
scrubber.process({
:first_name => "Chris",
:last_name => "Wyckoff",
:email => "foo@yahoo.com",
:phone => "8011231234",
:country => "US"
})
Saturday, March 19, 2011

48. scrubber = Scrubber.configure do |s|
s.scrub(:first_name).as(:invalid).if(:blank)
s.scrub(:last_name).as(:invalid).if(:blank)
s.scrub(:email).as(:invalid).if(:blank)
s.scrub(:phone).as(:invalid).if(:blank)
s.scrub(:first_name).as(:invalid).unless(:kid_friendly)
s.scrub(:last_name).as(:invalid).unless(:kid_friendly)
s.scrub(:email).as(:invalid).unless(:kid_friendly)
s.scrub(:country).as(:filtered).if {|lead| lead.contact.country == 'Other'}.and_warn
("Only requests from the United States can be accepted at this time")
s.scrub_with(:email).as(:filtered)
s.scrub_with(:education_level).as(:filtered)
s.scrub_with(:duplicate).as(:filtered)
end
scrubber.process({
:first_name => "Chris",
:last_name => "Wyckoff",
:email => "foo@yahoo.com",
:phone => "8011231234",
:country => "US"
})
Saturday, March 19, 2011

49. scrubber = Scrubber.configure do |s|
s.scrub(:first_name).as(:invalid).if(:blank)
s.scrub(:last_name).as(:invalid).if(:blank)
s.scrub(:email).as(:invalid).if(:blank)
s.scrub(:phone).as(:invalid).if(:blank)
s.scrub(:first_name).as(:invalid).unless(:kid_friendly)
s.scrub(:last_name).as(:invalid).unless(:kid_friendly)
s.scrub(:email).as(:invalid).unless(:kid_friendly)
s.scrub(:country).as(:filtered).if {|lead| lead.contact.country == 'Other'}.and_warn
("Only requests from the United States can be accepted at this time")
s.scrub_with(:email).as(:filtered)
s.scrub_with(:education_level).as(:filtered)
s.scrub_with(:duplicate).as(:filtered)
end
scrubber.process({
:first_name => "Chris",
:last_name => "Wyckoff",
:email => "foo@yahoo.com",
:phone => "8011231234",
:country => "US"
})
Saturday, March 19, 2011

50. scrubber = Scrubber.configure do |s|
s.scrub(:first_name).as(:invalid).if(:blank)
s.scrub(:last_name).as(:invalid).if(:blank)
s.scrub(:email).as(:invalid).if(:blank)
s.scrub(:phone).as(:invalid).if(:blank)
s.scrub(:first_name).as(:invalid).unless(:kid_friendly)
s.scrub(:last_name).as(:invalid).unless(:kid_friendly)
s.scrub(:email).as(:invalid).unless(:kid_friendly)
s.scrub(:country).as(:filtered).if {|lead| lead.contact.country == 'Other'}.and_warn
("Only requests from the United States can be accepted at this time")
s.scrub_with(:email).as(:filtered)
s.scrub_with(:education_level).as(:filtered)
s.scrub_with(:duplicate).as(:filtered)
end
scrubber.process({
:first_name => "Chris",
:last_name => "Wyckoff",
:email => "foo@yahoo.com",
:phone => "8011231234",
:country => "US"
})
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51. Lather, Rinse, Repeat
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52. Monolithic Rails
App
Lead
Qualification
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53. Monolithic Rails
App
Lead Lead
Qualification Delivery
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54. Cohesion
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55. Qualification Service
Factory
Scrubber Scrubbing DSL
Conditions Operands
Scrubbing Engine
Parameterized
Zip Phone Email
Rule
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56. Delivery Service
Field Mapper Lead Formatter
Phone Date Case Truncate Get/Post Email FTP/SFTP Custom
Lead Deliverer Response Handler
Get/Post Email FTP/SFTP Custom
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57. Adhesion
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58. Monolithic Rails
App Company
Controller
Contact
Lead
Invitation Contact Demographic
Status
Enrollment
Degree
LeadProcess Level
Controller Lead
Study
Program Company
Area
Referral
Leads
School Delivery
Controller Budget
Client
Search
Programs
Campus Budget Budget Controller
Reports Caps Caps
Search
Controller
Result Campus
Location Campus
Schools Budgets Locations
Controller Controller Controller
Saturday, March 19, 2011

59. 2. Operate Asynchronously
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60. Client 1
Monolithic Rails
App
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61. Client 1
Monolithic Rails
App
Client 2
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62. Client 1
Monolithic Rails
App
Client 2
Client 3
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63. Client 1
Monolithic Rails
App
Lead
Delivery Client 2
Client 3
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64. Lead
Client 1
Monolithic Rails Delivery
App
Lead
Client 2
Delivery
Lead
Client 3
Delivery
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65. Lead
Client 1
Monolithic Rails Delivery
App
Lead 200 ms
Client 2
Delivery
Lead
Client 3
Delivery
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66. Lead
Client 1
Monolithic Rails Delivery
App
Lead 200 ms
Client 2
Delivery
Lead 4000 ms
Client 3
Delivery
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67. Lead 10000 ms
Client 1
Monolithic Rails Delivery
App
Lead 200 ms
Client 2
Delivery
Lead 4000 ms
Client 3
Delivery
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68. 3. Make Incremental Changes
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69. Client 1
Monolithic Rails
App
Lead Delivery Client 2
Client 3
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70. Monolithic Rails
Client 1
App
Client 1
Router
Lead Client 2
Delivery
Client 3
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71. Monolithic Rails
Client 1
App
Client 1
Router
Lead Client 2
Delivery
Client 3
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72. class DeliveryRouter
def self.route(lead)
if(publishable_to_new_delivery?(self))
DeliveryRouter.publish(lead)
else
lead.submit
end
end
def self.publish(lead)
Bunny.publish(:lead_delivery, DeliveryMapper.map(lead))
end
def self.publishable_to_new_delivery?(lead)
lead.school.active_for_new_delivery?
end
end
Saturday, March 19, 2011

73. class DeliveryRouter
def self.route(lead)
if(publishable_to_new_delivery?(self))
DeliveryRouter.publish(lead)
else
lead.submit
end
end
def self.publish(lead)
Bunny.publish(:lead_delivery, DeliveryMapper.map(lead))
end
def self.publishable_to_new_delivery?(lead)
lead.school.active_for_new_delivery?
end
end
Saturday, March 19, 2011

74. class DeliveryRouter
def self.route(lead)
if(publishable_to_new_delivery?(self))
DeliveryRouter.publish(lead)
else
lead.submit
end
end
def self.publish(lead)
Bunny.publish(:lead_delivery, DeliveryMapper.map(lead))
end
def self.publishable_to_new_delivery?(lead)
lead.school.active_for_new_delivery?
end
end
Saturday, March 19, 2011

75. class DeliveryMapper
def self.map(lead)
{
:first_name => lead.contact.first_name,
:last_name => lead.contact.last_name,
:address => lead.contact.address,
:city => lead.contact.city,
:state => lead.contact.state,
:zip => lead.contact.zip,
:phone => lead.contact.phone,
:email => lead.contact.email,
:client_id => lead.client.id,
:lead_id => lead.id,
...
}
end
end
Saturday, March 19, 2011

76. class DeliveryRouter
def self.route(lead)
if(publishable_to_new_delivery?(self))
DeliveryRouter.publish(lead)
else
lead.submit
end
end
def self.publish(lead)
Bunny.publish(:lead_delivery, DeliveryMapper.map(lead))
end
def self.publishable_to_new_delivery?(lead)
lead.school.active_for_new_delivery?
end
end
Saturday, March 19, 2011

77. Monolithic Rails
Client 1
App
Client 1
Router
Lead Client 2
Delivery
Client 3
Saturday, March 19, 2011

78. Client 1
Monolithic Rails
App
Lead
Legacy Delivery Code Delivery Client 2
Client 3
Saturday, March 19, 2011

79. What Did We Gain?
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80. Speed
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81. Maintainability
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82. Testability
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83. Composability
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84. Lead Lead
Source Qualification Delivery
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85. Lead Lead Lead
Source Qualification Assignment Delivery
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86. Lead Lead Call
Source Qualification Delivery Center
Call Lead
Delivery Client
Center
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87. Lead Lead
Assignment Delivery
Lead Lead
Qualification Delivery
Lead Call Lead
Delivery Delivery Client
Center
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88. Education
Employment
Lead Lead
Qualification Delivery
Loan Financing
Saturday, March 19, 2011

89. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Reporting
Budget
Admin Service
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90. {
'event':'delivery',
'status':'accepted',
'lead_id':'1234',
'timestamp':'2011-02-23 08:09:01',
'lead_details':{
...
}
}
Saturday, March 19, 2011

91. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Reporting
Budget
Admin Service
Saturday, March 19, 2011

92. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Reporting
Budget
Admin Service
Saturday, March 19, 2011

93. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Reporting
Budget
Admin Service
Saturday, March 19, 2011

94. Lead Lead Email Lead
Qualification Delivery Remarketing Conversion
RabbitMQ
Reporting
Budget
Admin Service
Saturday, March 19, 2011

95. What Did We Risk?
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96. Maintainability
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97. Testability
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98. Overly Decomposed Services
Combat over-decomposition by
consolidating code w/o necessarily
isolating it as a ser vice
1) gems
2) local CouchDB stores that sync w/ a
master store
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99. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
Field Rules
Formatting Engine
Saturday, March 19, 2011

100. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
Field Rules
Formatting Engine
Saturday, March 19, 2011

101. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
Field Rules
Formatting Engine
Saturday, March 19, 2011

102. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
Field Rules
Formatting Engine
Saturday, March 19, 2011

103. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
Field Rules
Formatting Engine
Saturday, March 19, 2011

104. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
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105. Lead
Delivery
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106. Lead Lead Email
Qualification Delivery Remarketing
Survey
Engine
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107. Saturday, March 19, 2011

108. Map Your Architecture
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109. 1) http://www.vanderburg.org/Blog/Software/Development/
cohesion.rdoc
2) http://www.martinfowler.com/blikiStranglerApplication.html
3) http://www.eaipatterns.com/docs/EDA.pdf
Saturday, March 19, 2011

110. Saturday, March 19, 2011

111. Thank You.
Questions?
Saturday, March 19, 2011