Rails Data Recovery (the Violent way)

In this presentation, you'll learn how to recover Rails data from log file. This approach is database agnostic and could be adapted for many Rails apps.

Transcript

1. Rails Data Recovery the VIOLENT way Trung Lê @joneslee85 http://ruby-­‐journal.com Thursday, 13 June 13
2. My precioussss... Thursday, 13 June 13
3. Data Backup •Daily Slice backup •Daily DB backup •Daily Assets backup Thursday, 13 June 13
4. naïve Thursday, 13 June 13
5. It was one beautiful afternoon Thursday, 13 June 13
6. Thursday, 13 June 13
7. DO NOT PANIC Thursday, 13 June 13
8. What to do? •Write down things to be done in checklist •Redirect to graceful warning page •Assure customer (white lies) •Backup existing slice •Work in pair Thursday, 13 June 13
9. Restore the last good backup Thursday, 13 June 13
10. New data is still not recovered Thursday, 13 June 13
11. Sorry boss, I could not restore all data today... Thursday, 13 June 13
12. Think! You must think! Thursday, 13 June 13
13. Restore lost data with RAILS log/production.log Thursday, 13 June 13
14. See through the lines Thursday, 13 June 13
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18. Just kidding! Thursday, 13 June 13
19. Concept log/ production.log Parser Mechanize Extract HTTP query params Mass-Replicate HTTP requests Identify needed HTTP request details Thursday, 13 June 13
20. Request params extract •Could be huge in size ~ slow read •Contains ‘noise’ details •Could be generated with custom logger Thursday, 13 June 13
21. Reduce the log size •Split into many small files with UNIX’s split •Scope the lines by timestamp Thursday, 13 June 13
22. Clean up ‘noise’ •Assume you are using default Rails logger •Delete all but lines starting with: •Started GET|POST|PUT|DELETE •Parameters: {.*} •Sublime Text’s useful shortcut: •Ctrl + ⌘ + G •Shift + Ctrl + K Thursday, 13 June 13
23. Hacking Time Thursday, 13 June 13
24. Thursday, 13 June 13
25. Main methods •login(): faux-authentication •make_call(): •Convert hash to HTTP Query params •Only perform HTTP request with mechanize Thursday, 13 June 13
26. Bypassing authentication Thursday, 13 June 13
27. Bypassing authentication Thursday, 13 June 13
28. Ruby hash <-> HTTP params •mechanize use HTTP query hash •Should be able to convert nested hash for Rails `accepts_nested_attributes` Thursday, 13 June 13
29. QueryParams encoder Thursday, 13 June 13
30. Thursday, 13 June 13
31. Thursday, 13 June 13
32. Run and verify results Thursday, 13 June 13
33. Lesson Learned •Backup before applying things on production •Backup two to three times a day •Asking for confirmation for any rake tasks on production •Teamwork makes difference! Thursday, 13 June 13
34. Thank you @joneslee85 Thursday, 13 June 13