Elixirschool: Instrumenting Phoenix with Telemetry

[SophieDeBenedetto]

I'm working on a side project exploring Elixir's Telemetry offerings and hoping to wrap up the code portion in the next week or so. I think there are a number of opportunities for content on observability in Elixir with Telemetry. I'd love to produce either a series of blog posts or lessons that along the lines of:

• Intro to observability - what is it/why do we need it
• OOTB instrumentation with Elixir Telemetry in Phoenix - Ecto and Phoenix emit a set of pre-defined Telemetry events from source code that you can opt-in to listening to. This section will cover the following Telemetry events and include a look at setting up your Telemetry module to opt-in to them as well as a long at the Phoenix and/or Ecto source code that emits the event "for free".
  
  
  
  • Request counts and durations
  
  
  • Ecto query counts and durations
  
  
  • Channel and socket metrics
  
  
  • VM monitoring
  
  
• Custom instrumentation with Telemetry
  
  
  
  • Custom Telemetry events
  
  
  • Custom Telemetry polling
  
  
• Telemetry reporting options - StatsD, Prometheus, DogStatsD
• Telemetry under the hood - a deeper dive into Telemetry source code to understand how Telemetry library "listens" for emitted events and handles them with the appropriate handler (its not a GenServer! Its ETS!)

I'm leaning towards building these as a set of lessons that walks a user through adding instrumentation to an existing dummy Phoenix app that we supply.

What do others think? Would this maybe make more sense as a blog post? I'm leaning toward lesson b/c I've been on something of an observability crusade lately and am trying to make this kind of work more of a "first class citizen" when it comes to the development lifecycle. One of the very cool things about Elixir and Phoenix right now is that it treats observability like a first class citizen thanks to the Telemetry library and its robust "Out Of The Box" event reporting.

[SophieDeBenedetto]

I'm almost done with a draft of an article that covers:

• Intro to Telemetry
• Telemetry under the hood

Will open for review this weekend, likely as a blog post for now and we can move to a series of lessons later if we think that would be a good fit/addition.

[doomspork]

@SophieDeBenedetto can we close this now?

[SophieDeBenedetto]

yep!