It's time to talk about distributed systems: what are they, why you should be writing one, and what to look for while doing so. We'll cover the basics, understand some of the technology behind it - like REST, MQ with AMQP, ZeroMQ, etc - and discuss things we're doing at Heroku to avoid the pitfalls of a distributed architecture.

1. What Every
Programmer Should
Know About
Distributed Systems
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2. What Every
Programmer Could
Possibly Want To Know
About Me
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4. Friday, November 11, 11

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7. What Every
Programmer Should
Know About
Distributed Systems
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8. I
Definition
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9. A distributed system
consists of multiple
autonomous applications
that interact with each other to
achieve a common goal.
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10. II
Code Granularity
Photo by Matt Gibson
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11. print "Converting Celsius or Fahrenheit? "
option = gets[0,1].downcase
case option
when "c"
print "Convert C: "
celsius = gets.to_i
fahrenheit = celsius * 9/5 + 32
puts "#{celsius}C = #{fahrenheit}F"
when "f"
print "Convert F: "
fahrenheit = gets.to_i
celsius = (fahrenheit - 32) * 5/9
puts "#{fahrenheit}F = #{celsius}C"
end
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12. def main
convert(pick_unit)
end
def pick_unit
print "Convert Celsius ou Fahrenheit? "
gets[0,1].downcase
end
def convert(unit)
case unit
when "c": convert_celsius
when "f": convert_fahrenheit
end
end
...
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13. Ideal Granularity
Somewhere in between
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14. Units & OO
• Methods
• Classes
• Packages
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15. Units & Languages
• Ruby # sinatra.rb
module Sinatra
• Java class Application
...
• PHP class Event
...
module Streaming
class FileStreamer
...
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16. Units & Languages
• Ruby
• Java
• PHP $ javac Sinatra.java
sinatra.java:5: class Application is public, should be
declared in a file named Application.java
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17. Units & Languages
• Ruby
• Java
• PHP
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18. Units & Architecture
• Applications
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19. III
The Evolution of Óbidos
From Google Maps
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21. Heroku
• Instance management
• Billing & invoices
• Process orchestration
• Public API
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22. Heroku
• Instance management
• Billing & invoices
• Process orchestration
• Public API
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23. Heroku
• Instance management
• Billing & invoices
• Process orchestration
• Public API
Friday, November 11, 11

24. Heroku
• Instance management
• Billing & invoices
• Process orchestration
• Public API
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25. IV
Developing the Medium
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26. Problem:
?
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27. Share the Database
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28. OT
O NShare the Database
D
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29. REST
RestClient.get "host/users/1" get "/users/:id" do |id|
user = User.find(id)
user.to_json
end
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30. MQ
AMQP.start(:host => "1.2.3.4") do AMQP.start(:host => "1.2.3.4") do
q = MQ.new.queue("user.created") q = MQ.new.queue("user.created")
q.publish(:email => "pedro@heroku.com") q.subscribe do |msg|
end ...
end
end
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31. V
Challenges
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32. Challenges
• Versioning
• Testing
• Authentication
• Development environment
• Visual consistency
• Deploying
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33. Summary
1. Definition
2. Code Granularity
3. The Evolution of Óbidos
4. Developing the Medium
5. Challenges
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34. Thank you!
pedro@heroku.com
http://pedro.heroku.com
@ped
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