Digging Deep with ActiveSupport::Notifications

ActiveSupport::Notifications is a powerful, under-utilized library which makes it easy to instrument and monitor your code. Rails exposes a tons of performance information which is easy to access and you can create your own events with a single line of code. This talk explores the basics of ActiveSupport::Notifications and gets into powerful techniques you can use to super-charge your monitoring and instrumentation.

Transcript

1. Digging Deep With
   ActiveSupport::
   Noti cations
   Wednesday, April 25, 12
   

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2. Let’s Talk...
   • What is ActiveSupport::Noti cations?
   • Why you should care
   • How it works
   • What you can do with it
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3. The Basics of
   AS::Noti cations
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4. • AS::Noti cations provides a simple, exible
   messaging system for instrumenting
   • Lots of valuable data is already exposed by
   Rails’ built-in instrumentation
   • Provides an easy path for performance
   monitoring what you care about in your
   application
   • Log & track what matters to you!
   Why you should care
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5. “What gets measured
   gets managed”
   - Peter Drucker
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6. production !=
   development
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7. What Happened?
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8. How It Works
   • #subscribe - ask to receive
   instrument data
   • #instrument - signal event or
   track data about operation
   (duration / exceptions)
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9. #instrument
   Message Name
   (what you #subscribe to)
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10. #instrument
    Message Name
    (what you #subscribe to)
    Extra Arguments
    (passed as payload to #subscribe)
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11. #instrument
    Message Name
    (what you #subscribe to)
    Extra Arguments
    (passed as payload to #subscribe)
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12. #instrument
    Message Name
    (what you #subscribe to)
    Extra Arguments
    (passed as payload to #subscribe)
    Time Objects
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13. #instrument
    Message Name
    (what you #subscribe to)
    Extra Arguments
    (passed as payload to #subscribe)
    Time Objects
    Unique Message ID
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14. #instrument
    Message Name
    (what you #subscribe to)
    Extra Arguments
    (passed as payload to #subscribe)
    Time Objects
    Payload
    Unique Message ID
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15. #instrument
    (Block Form)
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16. #instrument
    (Block Form)
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17. #instrument
    (Block Form)
    Duration
    (difference between these)
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18. #instrument
    (Exceptions)
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19. #instrument
    (Exceptions)
    Exception Type
    (as string, not class)
    Exception Message
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20. #subscribe
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21. #subscribe
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22. #subscribe
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23. event#parent_of?
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24. #subscribe
    (using regular expressions)
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25. Rails Instrumentation
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26. Rails Instrumentation
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27. Rails Instrumentation
    Namespaced
    (right to left)
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28. Performance Monitoring
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29. Rails Request Time
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30. Requests by Server
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31. Slow Requests
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32. Slowest Req by Server
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33. Error Count
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34. SQL Monitoring
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35. SQL Monitoring
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36. Queries by Instance
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37. Queries by Instance
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38. SELECTs by Model
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39. Wednesday, April 25, 12
    

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40. Wednesday, April 25, 12
    

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41. What to do with
    instrumented data?
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42. Custom Logging
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43. New Relic Tracking
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44. Librato Metrics / StatsD
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45. Wednesday, April 25, 12
    

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46. KISS metrics
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47. Save Data For Later
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48. ...and more
    • Google Analytics events
    • Camp re / HipChat alerts
    • Schedule background jobs
    • Fire web hooks
    • etc
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49. Performance Notes
    • By default Rails calls subscribers in the
    thread where instrumentation took place
    • Consider backgrounding slow subscribers
    • Dispatcher can be replaced by your own
    queue system (set AS::Noti cations.noti er)
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50. #unsubscribe
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51. Power Moves
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52. Wednesday, April 25, 12
    

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53. Conditional
    Instrumentation
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54. Wednesday, April 25, 12
    

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55. Instrument Per User
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56. Instrument Per User
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57. Wednesday, April 25, 12
    

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58. Bot Up Your Life
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59. Simplifying Repetitive
    Instrumentation
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60. Just Forward It
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61. Simplifying Repetitive
    Subscribers
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62. LogSubscriber
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63. LogSubscriber
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64. LogSubscriber
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65. LogSubscriber
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66. LogSubscriber
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67. LogSubscriber
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68. LogSubscriber
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69. Use Outside of Rails
    • activesupport/noti cations can be required
    by itself, only needs securerandom to work
    • provides a good abstract interface for
    instrumentation
    • activesupport/log_subscriber is a separate
    library, can be required if needed
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70. Supporting #instrument
    in your Gems
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71. Faraday Instrumentation
    Custom
    Event Name
    Request Environment
    Passed as Payload
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72. Excon Instrumentation
    Allows
    Custom
    Instrumentor
    Custom
    Event Prefix
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73. Wednesday, April 25, 12
    

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74. Wednesday, April 25, 12
    

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75. Wednesday, April 25, 12
    

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76. Wednesday, April 25, 12
    

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77. Discuss Conventions
    for AS::Noti cations
    in Your Team
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78. In closing...
    • AS::Noti cations provides a simple
    message-based system for
    instrumentation
    • Use what Rails gives you, create what it
    doesn’t
    • Track what you want, track what matters
    to you!
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79. Questions?
    Matt Sanders
    twitter: @nextmat
    https://github.com/nextmat
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