samullen / metrix

A tiny library to simplify measuring the execution time of code blocks

Metrix

A tiny library to simplify measuring the execution time of code blocks.

Overview

Metrix is a module you can use in your Elixir applications to simplify measuring and relaying the results to Telemetry.

When incorporated into your modules, you provide measure/2 the event name to send measurements to, and the block of code you want to measure. measure/2 then sends the following data to your Telemetry event handler:

• measurement: This is a Map with :duration as the key. The value is in microseconds
• metadata: The value returned from the block as a map in the form %{response: results}. Extra metadata can be provided to measure/3 as a Map. The resulting metadata will be a merging of what's provided and the response/results. Example: measure([:event, :name], %{conn: conn}), do: ...

Example

Here's a simple example of how you might use Metrix. Below, we wrap a call to System.sleep/1 and IO.puts/2 in the #measure/2 macro. We also provide the Telemetry event name against which we want to capture data. Whenever run/0 is executed it measures the elapsed time and reports the duration to any Telemetry event handlers set up to match on [:my_app, :event, :name].

defmodule MyApp do
  use Metrix

  def run do
    measure([:my_app, :event, :name]) do
      System.sleep(1_000)
      IO.puts "Hello, World!"
    end
  end
end

An example event handler might look like this:

def handle_event([:my_app, :event, :name], %{duration: duration}, metadata, _config) do
  IO.puts "#{duration}"
  IO.inspect metadata
end

Installation

If available in Hex, the package can be installed by adding metrix to your list of dependencies in mix.exs:

def deps do
  [
    {:metrix, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/metrix.

Copyright and License

Metrix is copyright (c) 2020 Samuel Mullen.

Metrix source code is released under Apache License, Version 2.0.

See LICENSE and NOTICE files for more information.