Code Forensics
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This document outlines techniques for debugging and investigating software issues like a code forensics expert. It recommends avoiding panicking and doing multiple things at once. Follow a scientific process by writing down facts, having theories, and getting a debugging partner. Use tools like observability, debug tricks, and Linux tools. Analyze code changes and previous working versions. Document investigations through post-mortems, root cause analyses, and retrospectives to prevent future issues.
Code Forensics
- 2. @diego_pacheco ❏ Cat's Father ❏ Head of Software Architecture ❏ Agile Coach ❏ SOA/Microservices Expert ❏ DevOps Practitioner ❏ Speaker ❏ Author diegopacheco http://diego-pacheco.blogspot.com.br/ About me... https://diegopacheco.github.io/tinyurl.com/diegopacheco
- 3. Things we will talk about... Things you should avoid. DON'TS01 Science 101 How to run a investigation02 Observability, Debug Tricks, Linux Tools... Tools & Tricks03 Post Mortems, RCAs and Retrospectives Closing the Case04
- 4. Don'ts
- 5. Don't: FREAK OUT ❏ Avoid extra pressure on yourself ❏ Avoid worry about time. ❏ Avoid making comparisons like this should be done in 1h or so. ❏ As time pass is easy to Freak Out ❏ Making progress is your friend, don't nail it down only about solving the mystery. ❏ Your eyes can trick you, use tools. ❏ Make sure you do things properly. ❏ Comparing Strings ❏ Read Errors Carefully. ❏ Don't forget to Breath
- 6. Don't: Do two many things at time. ❏ Don't change 2 things at the time. ❏ Code ❏ Vars / Config ❏ Trys ❏ One Hypotesy at the time ❏ Otherwise how do you know what did what? ❏ You need to be: ❏ Methodical ❏ Boring ❏ Slow
- 7. How to Run a investigation Science 101 Have Theories Write Down Facts Have a Partner (Pair Programing) Minimize Investigation Efforts
- 8. Science 101
- 9. Science 101: Do we have a smoking gun?
- 10. Minimize Investigation Efforts 4% of code == 72% of defects (Code as Crime Scene)
- 11. Have Theories ❏ It's a like a guessing game, how the murder happen? ❏ Think on most likely thing it could be. ❏ There are classical Offenders like: ❏ NPE Lack of validation/test ❏ Code Change ❏ Config Change ❏ Credentials Change ❏ Typo somewhere ❏ Lack of Security groups ❏ Not enough Resources (memory, space) ❏ OOM Killer
- 12. Write down Facts ❏ Write down (paper, txt file, evernote, google docs) ❏ Write Important fact like: ❏ Class Names, Methods, Variables ❏ Make sure you don't get lots. ❏ It's easy to forget important pieces of information when you are worried and want to fix the issue fast.
- 13. Have a Partner (Pair Programing)
- 14. Have a Partner (Pair Programing)
- 15. Have a Partner (Pair Programing)
- 16. Tools & Tricks ❏ Observability ❏ Debug tricky's ❏ Linux Tools ❏ Write your own tools
- 17. Observability
- 18. —Filipe Fortes "Debugging is like being the detective in a crime movie where you are also the murderer." -
- 19. Debug tricks ❏ Know your IDE. ❏ Remote Debugging. ❏ Debug tricks like: ❏ Conditionals ❏ Log Expressions ❏ Runtime eval ❏ Exception Breakpoints ❏ Field Break points
- 20. Linux Tools
- 21. Write your own tools ❏ Help to nail down problems faster. ❏ Simple Utilitary. ❏ Program or scripts (Groovy, Python , Rust, Go). ❏ Quick diagnostics.
- 22. Could you compare with something else? ❏ It's very likely the issue is a code change, so maybe was working before. Some digging is needed. ❏ Not always possible (i.g new feature) ❏ Use diff tools. ❏ Compare previous versions that worked. ❏ Run previous tests that worked. ❏ Debug and write down differences.
- 23. Closing the Case Fix, Share & Improve ❏ Adding More Tests ❏ Post Mortems ❏ RCAs ❏ Retrospectives
- 24. Adding more Tests ❏ Boys Scout rules. ❏ Closing the Case means you found the issue. ❏ So we need to create test to simulate the issue. ❏ Having the test will proof we don't suffer again.
- 25. Closing the Case: Post Mortems
- 26. Closing the Case: RCA ❏ Similar to Post Mortems. ❏ Lean tool. Can be used with: 5 whys, fishbone and other system thinking tools. ❏ Excel file: ❏ Issue ❏ classification ❏ Why it happen ❏ How we make sure it does not happen again
- 27. Closing the Case: Retrospectives