1. LEGACY OR
REVENANT
CODE
SERGEY
SERGYENKO
CEO, Cybergizer
BELARUS RUBY USER GROUP

2. https://twitter.com/tenderlove/status/1308237713464635393

3. https://github.com/chrislgarry/apollo-11

6. Legacy Code is code inherited
from another developer or team
which uses older technologies
that are no longer supported or
have been superceded by a newer
version. Many programmers say
that “code becomes legacy code
as soon as it’s writtern”

7. The reason that programmers think the old code is a
mess is because of a cardinal, fundamental law of
programming:
IT’S HARDER TO READ CODE
THAT TO WRITE IT

8. There are TWO KINDS of
software: the one that
people complain about and
the one that nobody uses.

9. LEGACY CODE
ALWAYS WINS OVER
GOOD CODE

11. HOW TO CREATE
GOOD LEGACY CODE?

12. The longer a piece of code lasts
in a codease, the
MORE VALUE it can deliver.
Customers don’t care about the
age of the code, they care about
WORKING SOFTWARE.

13. The Roman bridges of antiquity were very inefficient
structures. By modern standards, they used too much
stone, and as a result, far too much labour to build.
Over the years we have learned to build bridges more
efficiently, using fewer materials and less labour to
perform the same task.
- Tom Clancy (The Sum of All Fears)

14. Biological Systems, as a Human for
example, can’t be a legacy, b/c of
aging, but they can produce it and
measured by its Value.
HOW DO YOU
CREATE SYSTEMS
THAT SURVIVE?
HOW DO WE
CREATE SYSTEMS
THAT OUTLAST US?

15. Chad Fowler: https://www.youtube.com/watch?v=YruzQgWdv48

19. It all comes back to one
thing: CODE SURVIVES by
providing VALUE and being
DIFFICULT TO REPLACE
THE REVENANT CODE

20. ONE PAGE PROGRAM:
RECYCLE THE CODE:
KILL AND REPLACE
CODE PERMANENTLY
SMALL THINGS ARE
GOOD
IMMUTABLE DEPLOYMENS:
NEVER UPGRADE SOFTWARE ON
AN EXISTING NODE

21. MONITOR EVERYTHING:
https://github.com/testdouble/suture
USE IT TO ELABORATE BUSINESS REQSFAVOR MEASUREMENT OVER TESTING
TRACK GENERATIONS OF WINNERS:
PLAN VALIDATE COMPARE
CUT REFACTOR FALLBACK
RECORD VERIFY DELETE

22. THANK YOU! SERGEY
SERGYENKO
CEO, Cybergizer
BELARUS RUBY USER GROUP
@sergyenko