You Can't Miss What You Can't Measure - Steel City Ruby Conf 2013

Adrift at sea, a GPS device will report your precise latitude and longitude, but if you don't know what those numbers mean, you're just as lost as before. Similarly, there are many tools that offer a wide variety of metrics about your code, but other than making you feel good, what are you supposed to do with this knowledge? Let's answer that question by exploring what the numbers mean, how static code analysis can add value to your development process, and how it can help us chart the unexplored seas of legacy code.

Transcript

1. YOU CAN’T MISS WHAT YOU CAN’T MEASURE
3. Y’uh can’ git the’uh fruhm he’uh [You can’t get there from here]
11. RED ➭ GREEN ➭ REFACTOR
13. 1. Denial 2. Anger 3. Bargaining 4. Depression 5. Acceptance
14. 1. Depression 2. Bargaining 3. Anger 4. Acceptance 5. Denial
18. @customers = Person.find_by_contents(@phrase, :columns => ['first_name', 'last_name', 'business_name', 'email_address', 'phone1'], :include => { :contacts => :customer }, :limit => 50).collect { |person| person.contacts.collect { |contact| contact.customer } }.flatten
19. {10:51}[1.9.3]~/project:master ✓ ➭ git blame app/controllers/customers_... ... cf2ee204 (Kerri Miller 2012-02-18 12:09:22 -0700 36)
21. TEST COVERAGE
22. TEST COVERAGE C0 — coverage of lines of code C1 — coverage of branches C2 — coverage of paths
24. LINES OF CODE
25. LINES OF CODE {20:32}[1.9.3]~/project:master ✓ ➭ rake stats +----------------------+-------+-------+---------+---------+-----+-------+ | Name | Lines | LOC | Classes | Methods | M/C | LOC/M | +----------------------+-------+-------+---------+---------+-----+-------+ | Controllers | 2297 | 1566 | 18 | 106 | 5 | 12 | | Helpers | 177 | 137 | 0 | 18 | 0 | 5 | | Models | 3948 | 2522 | 35 | 272 | 7 | 7 | | Libraries | 164 | 92 | 4 | 12 | 3 | 5 | | Model specs | 2863 | 2143 | 1 | 2 | 2 | 1069 | | View specs | 5 | 3 | 0 | 0 | 0 | 0 | | Controller specs | 4283 | 3632 | 0 | 0 | 0 | 0 | | Helper specs | 152 | 108 | 0 | 0 | 0 | 0 | | Library specs | 51 | 36 | 0 | 0 | 0 | 0 | +----------------------+-------+-------+---------+---------+-----+-------+ | Total | 13940 | 10239 | 58 | 410 | 7 | 22 | +----------------------+-------+-------+---------+---------+-----+-------+ Code LOC: 4317 Test LOC: 5922 Code to Test Ratio: 1:1.4
26. STATIC vs DYNAMIC
27. "Data is easy. Information is hard."
28. COMPLEXITY
29. CYCLOMATIC
30. ASSIGNMENTS BRANCHES CONDITIONALS
31. class Test def blah a = eval "1+1" # 1.2 (a=) + 6.0 (eval) if a == 2 then # 1.2 (if) + 1.2(==) + 0.4 (fixnum) puts "yay" # 1.2 (puts) end end end # 11.2 total FLOG
32. Extract Method Decompose Objects Rethink your domain model FIXING COMPLEXITY
33. CHURN
34. app/models/user.rb = 84 app/models/invoice.rb = 88
35. Wonderland Trail Length: 47.2 miles
36. Wonderland Trail Length: 47.2 miles
37. app/models/user.rb = 84 app/models/invoice.rb = 88
41. {10:54}[1.9.3]~/project:master ✓ ➭ git blame app/models/subscription.rb ... c9ce82b4 (Kerri Miller 2012-05-18 10:19:47 -0700
42. {20:32}[1.9.3]~/project:master ✓ ➭ flog -a app/models/subscription.rb 1609.9: flog total 61.9: flog/method average 408.8: Subscription#update app/models/subscription.rb:472 323.2: Subscription#new app/models/subscription.rb:250 252.0: Subscription#reply app/models/subscription.rb:137 230.5: Subscription::send_notifications app/models/subscription.rb:78 33.6: Subscription#none 25.5: Subscription#can_expire? app/models/subscription.rb:155 11.7: Subscription::reject_no_ack app/models/subscription.rb:205 4.8: Subscription#initialize app/models/subscription.rb:64 4.4: Subscription#expire! app/models/subscription.rb:183 3.7: Subscription#unexpire! app/models/subscription.rb:194 3.4: Subscription#reason_text app/models/subscription.rb:172 2.2: Subscription#is_current? app/models/subscription.rb:178 2.0: Subscription#to_s app/models/subscription.rb:71
43. {20:33}[1.9.3]~/project:master ✓ ➭ flog -d app/models/subscription.rb 321.7: flog total 32.2: flog/method average 230.5: Subscription::send_notifications app/models/subscription.rb:78 47.8: branch 31.7: ticket 23.1: assignment 17.9: user 17.6: [] 12.2: empty? 9.8: support_queue 8.1: deliver 8.0: class 7.6: email_address 7.0: ==
44. {08:16}[1.9.3]~/project:master ✓ ➭ flog -a app/models/subscription.rb 52.8: Subscription::send_notifications app/models/subscription.rb:80 28.8: Subscription#none 25.5: Subscription#can_expire? app/models/subscription.rb:119 10.2: Subscription::set_mail_options app/models/subscription.rb:221 9.8: Subscription::email_staff app/models/subscription.rb:268 8.5: Subscription::filter_subscriptions app/models/subscription.rb:17 7.9: Subscription::email_reviewers app/models/subscription.rb:258 7.3: Subscription::email_subscribers app/models/subscription.rb:169 6.3: Subscription::subscriber_emails app/models/subscription.rb:204 5.0: Subscription::log_rate_limited app/models/subscription.rb:239 4.8: Subscription#initialize app/models/subscription.rb:65 4.7: Subscription::extract_email_addresses app/models/subscription.rb 4.6: Subscription::filter_rate_limited app/models/subscription.rb:248 4.4: Subscription#expire! app/models/subscription.rb:147 4.0: Subscription::wants_notifications_on_own_posts? app/models/subsc 3.7: Subscription#unexpire! app/models/subscription.rb:158 3.4: Subscription#reason_text app/models/subscription.rb:136 3.2: Subscription::valid_recipient? app/models/subscription.rb:187 2.4: Subscription::ok_to_email? app/models/subscription.rb:183 2.2: Subscription#is_current? app/models/subscription.rb:142 2.0: Subscription#to_s app/models/subscription.rb:73 1.5: Subscription::find_reviewers app/models/subscription.rb:254 1.4: Subscription::mail_subject app/models/subscription.rb:217
45. {08:43}[1.9.3]~/project:master ✓ ➭ flog -a app/models/subscription.rb 27.9: Subscription#none 25.5: Subscription#can_expire? app/models/subscription.rb:78 4.8: Subscription#initialize app/models/subscription.rb:65 4.4: Subscription#expire! app/models/subscription.rb:106 3.7: Subscription#unexpire! app/models/subscription.rb:117 3.4: Subscription#reason_text app/models/subscription.rb:95 2.2: Subscription#is_current? app/models/subscription.rb:101 2.0: Subscription#to_s app/models/subscription.rb:73 {08:43}[1.9.3]~/project:master ✓ ➭ flog -a app/models/subscriber_notifier.rb 136.6: flog total 8.5: flog/method average 54.1: SubscriberNotifier::send_notifications app/models/subscriber_notif 12.0: SubscriberNotifier::email_subscribers app/models/subscriber_notifi 10.2: SubscriberNotifier::set_mail_options app/models/subscriber_notifie 9.8: SubscriberNotifier::email_staff app/models/subscriber_notifier.rb 8.5: SubscriberNotifier::filter_subscriptions app/models/subscriber_not 7.9: SubscriberNotifier::email_reviewers app/models/subscriber_notifier 6.3: SubscriberNotifier::subscriber_emails app/models/subscriber_notifi 5.0: SubscriberNotifier::log_rate_limited app/models/subscriber_notifie 4.7: SubscriberNotifier::extract_email_addresses app/models/subscriber_ 4.6: SubscriberNotifier::filter_rate_limited app/models/subscriber_noti 4.0: SubscriberNotifier::wants_notifications_on_own_posts? app/models/s 3.2: SubscriberNotifier::valid_recipient? app/models/subscriber_notifie 2.4: SubscriberNotifier::ok_to_email? app/models/subscriber_notifier.rb
47. > gem install flay
48. STYLE & BEST PRACTICES rails_best_practices reek roodi pelusa
49. RUBOCOP
50. CANE from Square ABC, code style, documentation threshold failures
52. BRAKEMAN scans for security vulnerabilities Rails 2.x and 3.x CI plugins constantly updated
54. ★ @kerrizor ★ glass artist ★ vespa mechanic ★ lighting designer ★ poker player ★ software developer Kerri Miller