Continuous Delivery(CD) is a more and more popular in modern applications. When done right it simplifies processes, makes business people more in control and programmers/ops less stressed. But as always "with great power there must also come great responsibility". I will talk about: - what steps need to be taken to enable CD. - how it impacts applications architecture. - how to work without VCS branches - how it changes testing process and release management - what are the benefits and disadvantages CD

1. author: Łukasz Szydło
lukasz.szydlo@bottega.com.pl
Enabling Continuous Delivery

2. About me
Programmer/Architect/Consultant
Writes code mostly in Java
Fan of agility
Trainer at Bottega IT Solutions
Branch free since 2010 (with small break)
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3. Survey
Quick survey
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4. What is CD?
Our highest priority is to satisfy the
customer through early and
continuous delivery
of valuable software.
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5. Technics
- automated testing
- continuous integration
- continuous inspection
- continuous deployment
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6. Technics
- automated testing
- continuous integration
- continuous inspection
- continuous deployment
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7. Starting point
How big is your app?
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8. Starting point
How big is your app?
let’s define some unit
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9. Starting point
How about time it takes to run all
the tests?
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10. Starting point
How about time it takes to run all
the tests?
(on commodity hardware in a singe thread
given decent coverage )
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11. Slow tests
Reference test timing
Unit tests < 1ms
Integration tests < 50 ms
Acceptance tests - as fast as possible :)
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12. Divide and conquer
If your app is too big split it
- Micro services
- Micro applications
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13. Definition
Release != Deploy
Release - make feature accessible to users
Deploy - put the newest code on server
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14. How to release it?
Bottega Release

15. Bottega Release

16. Branches slow you down
{ “Source” : “http://www.whitewolfpack.com/2012/10/hapless-lion-cubs-clumsy-bid-to-climb.html”}
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17. Branches slow you down
{ “Source” : “http://nvie.com/posts/a-successful-git-branching-model/”}
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18. Branches slow you down
{ “Source” : “http://www.uni-2.co.uk/latest_news/7-best-things-to-get-your-hand-stuck-in/”}
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19. Introducing changes
Incremental Changes
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20. Introducing changes
Branching by abstraction
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21. Introducing changesBottega
class DefaultPurchaseService implements PurchaseService {
public Money calculateRabat(OrderNumber orderNo){
Order order = ordersRepository.load(orderNo);
RabatPolicy rabatPolicy = rabatPolicyFactory.get();
Money rabatValue = order.calculateRabat(rabatPolicy);
return rabatValue;
}
public void addProduct(OrderNumber orderNo,
ProductNumber productNo,
Quantity quantity){
Product product = productsRepository.load(productNo);
Order order = ordersRepository.load(orderNo);
order.addProduct(product, quantity,);
ordersRepo.save(order);
}
}

22. Introducing changes
Feature Switches
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23. Introducing changesBottega
class DefaultRabatPolicyFactory implements RabatPolicyFactory {
Map<Name, RabatPolicy> map = newMap()
.put(“default”, new DefRP())
.put(“newShiny”, new DefRP())
public RabatPolicy create(){
if(featureSwitcher.isNewRabatPolicyActive()) {
return map.get(newShiny);
} else {
return map.get(newShiny);
}
}
}

24. Automatic testing
Write your tests
and
make them fast
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25. Automatic testing
Bugs
- user can’t complete some action
- user can complete action wrong
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26. Ports&Adapters/Hexagonal/Onion
Architecture
{ “Source” : “http://www.natpryce.com/articles/000772.html”}
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27. Configuration
Make your app configurable
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28. Information and reporting
Monitor your process
- Static code analysis
- Process metrics
- Application monitoring
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29. Infrastructure
Infrastructure needs to enable
you to create small apps
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30. Summary
- Culture & Organization
- Design & Architecture
- Build & Deploy
- Tests & Verification
- Information & Reporting
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31. Q&A
Q&A
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