Ep 028: Fail Donut

Functional Design in Clojure

Christoph has gigs of log data and he's looking to Clojure for some help.

• Introducing a new topic.
• The last few weeks we focused on Twitter and automatically posting to it.
• Surprised by how much there is to talk about in a focused problem.
• "There will always be more problems for the world to solve."
• (01:53) Imagine if you will, the world of DonutGram!
• A fictitious social network where people post their donut experiences.
• This series is not about making DonutGram, but living DonutGram.
• "Oh, the dark underbelly of application development: support."
• "Let's take the shiny rock and flip it over and look at all the worms and bugs."
• We talked about forensic data before, and much of DevOps is about looking at that data.
• You want to paint the most complete story. It's a development problem too.
• Most of the time, forensic data is written to a log file. It's the first line of investigation.
• Imagine all of the components of your application speaking into one pipe, and you now get to reconstruct what happened.
• (05:59) Everything is rosy at DonutGram, but then users start having issues.
• Users get the "Fail Donut" and start posting that.
• We will be assuming the role of the heroic DevOps team.
• There is quite a bit of data written to the log file, more and more with each bugfix.
• We're going to use Clojure to investigate this problem.
• (08:50) What problems might we encounter?
• Problem 1: Size
  • No one configured log rotation!
  • The log file is too large to load for analysis.
• Problem 2: Unstructured data
  • Everything is a line or multiple lines.
  • We can build up layers of abstractions to gradually build understanding.
• Problem 3: Non-linear data
  • We want to tell a story about what went wrong.
  • Many times, the pieces of that story are in different areas of the log file, and must be collated.
  • There can be multiple competing stories.
  • The parts of the story are like dominoes. How do you know if the third domino is important without knowing that the first two have fallen?
• Problem 4: Alerts
  • "If you have a really good story to tell, how do you tell anyone about it?"
  • Alerts should be timely, depending on the audience.
• Call out to the audience: do you have battle stories about processing log files? Let us know!

Clojure in this episode:

• nil