Add support for custom DISTRIBUTION metric

.github/workflows/ci.yml

@@ -11,22 +11,22 @@ jobs:
     name: Code linting
     uses: lexmag/elixir-actions/.github/workflows/lint.yml@v2
     with:
-      otp-version: "24"
-      elixir-version: "1.14"
+      otp-version: "26"
+      elixir-version: "1.16"
 
   test:
     name: Test suite
     runs-on: ubuntu-20.04
 
     strategy:
       matrix:
-        otp: ["24"]
-        elixir: ["1.14"]
+        otp: ["26"]
+        elixir: ["1.16"]
         runtime_config: [true, false]
 
         include:
-          - otp: "20"
-            elixir: "1.6"
+          - otp: "26"
+            elixir: "1.16"
             runtime_config: false
 
     env:

lib/statix.ex

@@ -225,6 +225,24 @@ defmodule Statix do
   """
   @callback timing(key, value :: String.Chars.t(), options) :: on_send
 
+  @doc """
+  Same as `distribution(key, value, [])`.
+  """
+  @callback distribution(key, value :: String.Chars.t()) :: on_send
+
+  @doc """
+  Writes the given `value` to the StatsD distribution identified by `key`.
+
+  `value` is expected in milliseconds.
+
+  ## Examples
+
+      iex> MyApp.Statix.distribution("rendering", 12, [])
+      :ok
+
+  """
+  @callback distribution(key, value :: String.Chars.t(), options) :: on_send
+
   @doc """
   Writes the given `value` to the StatsD set identified by `key`.
 
@@ -330,6 +348,10 @@ defmodule Statix do
         Statix.transmit(current_statix(), :timing, key, val, options)
       end
 
+      def distribution(key, val, options \\ []) do
+        Statix.transmit(current_statix(), :distribution, key, val, options)
+      end
+
       def measure(key, options \\ [], fun) when is_function(fun, 0) do
         {elapsed, result} = :timer.tc(fun)
 
@@ -349,7 +371,8 @@ defmodule Statix do
         histogram: 3,
         timing: 3,
         measure: 3,
-        set: 3
+        set: 3,
+        distribution: 3
       )
     end
   end

lib/statix/packet.ex

@@ -44,7 +44,8 @@ defmodule Statix.Packet do
     gauge: "g",
     histogram: "h",
     timing: "ms",
-    set: "s"
+    set: "s",
+    distribution: "d"
   }
 
   for {name, type} <- metrics do

test/statix/overriding_test.exs

@@ -35,6 +35,10 @@ defmodule Statix.OverridingTest do
     super([key, "-overridden"], value, options)
   end
 
+  def distribution(key, value, options) do
+    super([key, "-overridden"], value, options)
+  end
+
   setup do
     connect()
   end
@@ -64,6 +68,11 @@ defmodule Statix.OverridingTest do
     assert_receive {:test_server, _, "sample-overridden:3|ms|#foo"}
   end
 
+  test "distribution/3" do
+    distribution("sample", 3, tags: ["foo"])
+    assert_receive {:test_server, _, "sample-overridden:3|d|#foo"}
+  end
+
   test "measure/3" do
     measure("sample", [tags: ["foo"]], fn ->
       :timer.sleep(100)

test/statix/pool_test.exs

@@ -18,7 +18,8 @@ defmodule Statix.PoolingTest do
         {:histogram, [3]},
         {:timing, [3]},
         {:measure, [fn -> nil end]},
-        {:set, [3]}
+        {:set, [3]},
+        {:distribution, [3]}
       ]
       |> Enum.map(fn {function, arguments} ->
         apply(__MODULE__, function, ["sample" | arguments])

test/statix_test.exs

@@ -155,27 +155,49 @@ defmodule StatixTest do
     refute_received _any
   end
 
+  test "distribution/2,3" do
+    __MODULE__.distribution(["sample"], 2)
+    assert_receive {:test_server, _, "sample:2|d"}
+
+    distribution("sample", 2.1)
+    assert_receive {:test_server, _, "sample:2.1|d"}
+
+    distribution("sample", 3, tags: ["foo:bar", "baz"])
+    assert_receive {:test_server, _, "sample:3|d|#foo:bar,baz"}
+
+    distribution("sample", 3, sample_rate: 1.0, tags: ["foo", "bar"])
+    assert_receive {:test_server, _, "sample:3|d|@1.0|#foo,bar"}
+
+    distribution("sample", 3, sample_rate: 0.0)
+
+    refute_received _any
+  end
+
   test "port closed" do
     close_port()
 
     assert capture_log(fn ->
              assert {:error, :port_closed} == increment("sample")
-           end) =~ "counter metric \"sample\" lost value 1 error=:port_closed\n\e[0m"
+           end) =~ "counter metric \"sample\" lost value 1 error=:port_closed"
 
     assert capture_log(fn ->
              assert {:error, :port_closed} == decrement("sample")
-           end) =~ "counter metric \"sample\" lost value -1 error=:port_closed\n\e[0m"
+           end) =~ "counter metric \"sample\" lost value -1 error=:port_closed"
 
     assert capture_log(fn ->
              assert {:error, :port_closed} == gauge("sample", 2)
-           end) =~ "gauge metric \"sample\" lost value 2 error=:port_closed\n\e[0m"
+           end) =~ "gauge metric \"sample\" lost value 2 error=:port_closed"
 
     assert capture_log(fn ->
              assert {:error, :port_closed} == histogram("sample", 3)
-           end) =~ "histogram metric \"sample\" lost value 3 error=:port_closed\n\e[0m"
+           end) =~ "histogram metric \"sample\" lost value 3 error=:port_closed"
 
     assert capture_log(fn ->
              assert {:error, :port_closed} == timing("sample", 2.5)
-           end) =~ "timing metric \"sample\" lost value 2.5 error=:port_closed\n\e[0m"
+           end) =~ "timing metric \"sample\" lost value 2.5 error=:port_closed"
+
+    assert capture_log(fn ->
+             assert {:error, :port_closed} == distribution("sample", 2.5)
+           end) =~ "distribution metric \"sample\" lost value 2.5 error=:port_closed"
   end
 end