Legacy codes

What's legacy codes? What should we do with it?

Transcript

1. Legacy Code Sleman, April 1st, 2016
2. What is legacy code? Code we’ve gotten from somewhere else Demoralising code (big ball of mud) Code without unit tests
4. Characteristics Poor Architectures Without tests Poor written documentation Oral documentation IT’S WORKING!!!
5. IF IT’S WORKING, THEN WHY CHANGE IT ???
6. Reasons to change Legacy Code Kill some BUGS! Add new FEATURES Do some OPTIMISATIONS Add new automations things ( tests, scaling, etc)
8. Reasons not to change Legacy Code It looks ugly I would like to see nicer code I want to use new shiny tools ….
9. What do we do? REWRITE?
10. BOOOOMMMM!!!
11. STOP!! DON’T REWRITE It takes time Need business analysis Features will keep coming Breeding new bugs
12. Working Code is OK
13. What do we do? You can rewrite but you cannot rewrite all Fight temptations to refactor a lot of codes DO IT SLOWLY AND CALMLY!!
14. 2 Kinds of Refactoring Edit and Pray Cover and Modify
15. Edit and Pray Steps Find boundaries Discover the codes Refactor / Rewrite Run it and do smoke tests Pray that everything is okay
16. Cover and Modify Steps Find boundaries Discover the code Start write tests around the to-be- refactored code Do refactor / rewrite Tests and ensure its working
17. Find Boundaries Act at one part of code at a time Domains FTW
18. Discover the Code Read documentations Interview previous developers Read the codes Try the codes
19. Prepare and Write Tests Surround it with tests ( integration, GUI, unit tests, exploratory tests ) Testing is an investment
20. Write Code to make it Pass! SELF EXPLANATORY! ^_^
21. THANKS!!