Code for step 8

lib/elixir_monitoring_prom/application.ex

@@ -23,6 +23,8 @@ defmodule ElixirMonitoringProm.Application do
       nil
     )
 
+    ElixirMonitoringProm.Metrics.setup()
+
     # List all child processes to be supervised
     children = [
       # Start the Ecto repository

lib/elixir_monitoring_prom/zip_codes/zip_codes.ex

@@ -1,6 +1,8 @@
 defmodule ElixirMonitoringProm.ZipCodes do
   alias ElixirMonitoringProm.{Repo, ZipCodes.ZipCode}
 
+  import Ecto.Query
+
   def get_zip_codes_in_radius(zip_code, radius_in_miles) do
     # Our raw Postgres query to get all the zip codes within a radius
     query =
@@ -30,5 +32,9 @@ defmodule ElixirMonitoringProm.ZipCodes do
     end
   end
 
+  def get_zip_code_info(zip) do
+    Repo.one(from zip_code in ZipCode, where: zip_code.zip_code == ^zip)
+  end
+
   defp miles_to_meters(miles), do: miles * 1609.344
 end

lib/elixir_monitoring_prom_web/controllers/brewery_controller.ex

@@ -1,10 +1,12 @@
 defmodule ElixirMonitoringPromWeb.BreweryController do
   use ElixirMonitoringPromWeb, :controller
 
-  alias ElixirMonitoringProm.Breweries
+  alias ElixirMonitoringProm.{Breweries, Metrics}
 
   def index(conn, %{"zip_code" => zip_code, "mile_radius" => radius}) do
     results = Breweries.get_breweries_in_radius(zip_code, String.to_integer(radius))
+    Metrics.increment_zip_code_search(zip_code)
+    Metrics.observe_radius_search(radius)
 
     json(conn, results)
   end

lib/metrics.ex

@@ -0,0 +1,39 @@
+defmodule ElixirMonitoringProm.Metrics do
+  use Prometheus.Metric
+
+  alias ElixirMonitoringProm.{ZipCode, ZipCodes.ZipCode}
+
+  def setup do
+    # Our counter for the number of searches against a particular zipcode.
+    # Given that there is a label 'geohash' each zip code gets its own counter.
+    Counter.new(
+      name: :elixir_app_zip_code_search,
+      help: "Counter for brewery zip code searches",
+      labels: [:zip_code, :geohash]
+    )
+
+    # The provided radius will fall into one of the defined buckets
+    Histogram.new(
+      name: :elixir_app_radius_search,
+      buckets: [1, 2, 5, 10, 20, 50],
+      help: "The radius that people are searching within for breweries"
+    )
+  end
+
+  def increment_zip_code_search(zip_code) do
+    zip_code
+    |> ElixirMonitoringProm.ZipCodes.get_zip_code_info()
+    |> case do
+      %ZipCode{point: %Geo.Point{coordinates: {long, lat}}} ->
+        geo_hash = Geohash.encode(lat, long)
+        Counter.inc(name: :elixir_app_zip_code_search, labels: [zip_code, geo_hash])
+
+      _ ->
+        :noop
+    end
+  end
+
+  def observe_radius_search(radius) do
+    Histogram.observe([name: :elixir_app_radius_search], String.to_integer(radius))
+  end
+end

mix.exs

@@ -51,7 +51,8 @@ defmodule ElixirMonitoringProm.MixProject do
       {:prometheus_ecto, "~> 1.4.3"},
       {:prometheus_phoenix, "~> 1.3.0"},
       {:prometheus_plugs, "~> 1.1.5"},
-      {:prometheus_process_collector, "~> 1.4.3"}
+      {:prometheus_process_collector, "~> 1.4.3"},
+      {:geohash, "~> 1.0.0"}
     ]
   end
 

mix.lock

@@ -11,6 +11,7 @@
   "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},
   "geo": {:hex, :geo, "3.1.0", "727e005262430d037e870ff364e65d80ca5ca21d5ac8eddd57a1ada72c3f83b0", [:mix], [], "hexpm"},
   "geo_postgis": {:hex, :geo_postgis, "3.1.0", "d06c8fa5fd140a52a5c9dab4ad6623a696dd7d99dd791bb361d3f94942442ff9", [:mix], [{:geo, "~> 3.1", [hex: :geo, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0 or ~> 4.0", [hex: :poison, repo: "hexpm", optional: true]}, {:postgrex, "~> 0.14", [hex: :postgrex, repo: "hexpm", optional: false]}], "hexpm"},
+  "geohash": {:hex, :geohash, "1.0.2", "d02f8c974704105d3c6cc7e722647319aa601c86169693710866a550277dc41e", [:mix], [], "hexpm"},
   "gettext": {:hex, :gettext, "0.17.0", "abe21542c831887a2b16f4c94556db9c421ab301aee417b7c4fbde7fbdbe01ec", [:mix], [], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},