Elixometer
A light wrapper around exometer.
Elixometer allows you to define metrics and subscribe them automatically to the default reporter for your environment.
Installation
Add the following to your dependencies in mix.exs:
{:elixometer, github: "pinterest/elixometer"}Then, add :elixometer to your applications. That's it!
Configuration
In one of your config files, set up an exometer reporter, and then register it to elixometer like this:
config(:exometer, report: [reporters: [{:exometer_report_tty, []}]])
config(:elixometer, reporter: :exometer_report_tty,
env: Mix.env,
metric_prefix: "myapp")Metrics are prepended with the metric_prefix, the type of metric and the environment name.
The optional update_frequency key of the :elixometer config controls the interval between reports. By default this is set to 1000 ms in the dev environment and 20 ms in the test environment.
Metrics
Defining metrics in elixometer is substantially easier than in exometer. Instead of defining and then updating a metric, just update it. Also, instead of providing a list of atoms, a metric is named with a period separated bitstring. Presently, Elixometer supports timers, histograms, gauges, and counters.
Timings may also be defined by annotating a function with a @timed annotation. This annotation takes a key argument, which tells elixometer what key to use. You can specify :auto and a key will be generated from the module name and method name.
Updating a metric is similarly easy:
defmodule ParentModule.MetricsTest do
use Elixometer
# Updating a counter
def counter_test(thingie) do
update_counter("metrics_test.\#{thingie}.count", 1)
end
# Timing a block of code in a function
def timer_test do
timed("metrics_test.timer_test.timings") do
OtherModule.slow_method
end
end
# Timing a function. The metric name will be [:timed, :function]
@timed(key: "timed.function") # key will be: prefix.dev.timers.timed.function
def function_that_is_timed do
OtherModule.slow_method
end
# Timing a function with an auto generated key
# The key will be "<prefix>.<env>.timers.parent_module.metrics_test.another_timed_function"
# If the env is prod, the environment is omitted from the key
@timed(key: :auto)
def another_timed_function do
OtherModule.slow_method
end
end