Measure your Rails app

So you've done a web app, you tested it, deployed it, and your first customers begin to use your product and share it to their friends. That's great! Now, how do you know how are they using your application? Are you sure of the impacts of your deployments? What if you doubled the response time by fixing a bug and didn't see it?

In order to watch your application behavior, you need real-time metrics.

What are exactly real-time metrics? What can you use to store and watch them? What are exactly RRDtool, Graphite, StatsD? Can we improve existing solutions?

Transcript

1. measure your rails app
2. metrics solutions going further
3. Jean-Daniel Guyot @jdguyot
5. metrics solutions going further
6. Statistics
7. Statistics ≠ Real-time metrics
8. Statistics = Play with your model
9. Statistics SELECT AVG(price), date_trunc('month', created_at) d FROM payments WHERE state = ‘paid’ GROUP BY d
10. 0 € 43 € 85 € 128 € 170 € dec. jan. feb. mar.
11. real-time metrics
12. real-time trends metrics
13. system application
14. system application
15. Good ol’ tools Syslog RRDtool Munin Cacti
18. data value Minute Hour Day Month Year
19. data compression 10 sec during 1 day 1 min during 1 week 10 min
20. issues No way to insert data on an irregular basis No way to insert data in the past Insert one value at a time (I/O performance issue)
21. metrics solutions going further
22. graphite
23. graphite Easy to use Combine graphs easily Apply functions Save graphs & dashboards (Python)
24. More than storage Whisper (DB) Carbon (Backend) Webapp (UI) inspired from RRDtool
25. timestamp key value
26. pimp my gaphite Whisper (DB) Carbon (Backend) Webapp (UI) Graphiti Graphene
27. sending data to graphite
28. App
29. App Graphite timestamp key value
30. issues
31. App Graphite OMGTCP!
32. App Graphite 2 values in 10 seconds interval: OVERWRITE
33. App Graphite Counters?
34. flickr StatsD (Perl)
35. etsy StatsD (Node.js)
36. Statsd Ruby, JS, C++, whatever Counters, Timers Automatic simple statistics values computation (95% percentile, average, …)
37. StatsD Graphite App
38. metrics solutions going further
39. issues
40. StatsD Graphite App Monitoring Maintenance 3 standalone apps =
41. 2 solutions
42. ambroise github.com/capitainetrain/ambroise
43. App Graphite Unicorn + after_fork + StatsD Ambroise =
44. ambroise Nothing to start Less code Simple
45. statsd + rabbitmq
46. StatsD Graphite App Classic architecture
47. StatsD Graphite App Add RabbitMQ RabbitMQ
48. RMQ Graphite App Detach StatsD StatsD MQ RMQ
49. statsd + rabbitmq No latency Fault-resistant Only one running app Simple
50. a few graphite tips
51. timestamp key value
52. folder.folder.key
53. tip #1 Pay attention to values overwriting Several machines: add a namespace per machine mystat.machine1.my_counter To get all stats: mystat.*.counter
54. tip #2 Use only 1 RabbitMQ for all the hosts (development machines/integration) hostname.app_name.mystat.machin e1.my_counter
55. Thanks.