Replace Mox with Patch

lib/kafkaex_lag_exporter/behaviours/kafka_utils_behaviour.ex

@@ -19,7 +19,7 @@ defmodule KafkaexLagExporter.KafkaUtils.Behaviour do
               {host :: atom, port :: non_neg_integer},
               list(binary),
               list(binary)
-            ) :: list(binary)
+            ) :: list({consumer_group :: binary, topics :: list(binary)})
 
   def connection(client), do: impl().connection(client)
 

lib/kafkaex_lag_exporter/consumer_offset.ex

@@ -29,10 +29,10 @@ defmodule KafkaexLagExporter.ConsumerOffset do
   def handle_info(:tick, state) do
     [endpoint | _] = state.endpoints
 
-    {consumer_lags, consumer_lag_sum} = KafkaexLagExporter.ConsumerOffsetFetcher.get(endpoint)
+    %{sum: lag_sum, lags: lags} = KafkaexLagExporter.ConsumerOffsetFetcher.get(endpoint)
 
-    KafkaexLagExporter.Metrics.group_lag_per_partition(endpoint, consumer_lags)
+    KafkaexLagExporter.Metrics.group_lag_per_partition(endpoint, lags)
-    KafkaexLagExporter.Metrics.group_sum_lag(endpoint, consumer_lag_sum)
+    KafkaexLagExporter.Metrics.group_sum_lag(endpoint, lag_sum)
 
     Process.send_after(self(), :tick, @interval)
 

lib/kafkaex_lag_exporter/consumer_offset_fetcher.ex

@@ -3,19 +3,24 @@ defmodule KafkaexLagExporter.ConsumerOffsetFetcher do
 
   require Logger
 
-  # TODO: change return type
+  alias KafkaexLagExporter.KafkaUtils
-  @spec get(KafkaexLagExporter.KafkaWrapper.endpoint()) :: {any(), any()}
+
+  # TODO fix type
+  @spec get(KafkaexLagExporter.KafkaWrapper.Behaviour.endpoint()) :: %{
+          lags: list(binary),
+          sum: list(binary)
+        }
   def get(endpoint) do
-    consumer_group_names = KafkaexLagExporter.KafkaUtils.get_consumer_group_names(endpoint)
+    consumer_group_names = KafkaUtils.get_consumer_group_names(endpoint)
 
     consumer_lags =
-      KafkaexLagExporter.KafkaUtils.topic_names_for_consumer_groups(
+      KafkaUtils.topic_names_for_consumer_groups(
         endpoint,
         [],
         consumer_group_names
       )
-      |> Enum.map(fn [consumer_group, topics] ->
+      |> Enum.map(fn {consumer_group, topics} ->
-        [consumer_group, get_lag_for_consumer(consumer_group, topics)]
+        {consumer_group, get_lag_for_consumer(consumer_group, topics)}
       end)
 
     consumer_lag_sum = get_lag_for_consumer_sum(consumer_lags)
@@ -26,13 +31,13 @@ defmodule KafkaexLagExporter.ConsumerOffsetFetcher do
   defp get_lag_for_consumer(consumer_group, topics) do
     topics
     |> Enum.flat_map(fn topic ->
-      KafkaexLagExporter.KafkaUtils.lag(topic, consumer_group, :client1)
+      KafkaUtils.lag(topic, consumer_group, :client1)
     end)
   end
 
   defp get_lag_for_consumer_sum(lags_per_consumer_group) do
     lags_per_consumer_group
-    |> Enum.map(fn [topic, lag_per_partition] -> [topic, sum_topic_lag(lag_per_partition, 0)] end)
+    |> Enum.map(fn {topic, lag_per_partition} -> {topic, sum_topic_lag(lag_per_partition, 0)} end)
   end
 
   defp sum_topic_lag([], acc), do: acc

mix.exs

@@ -39,7 +39,7 @@ defmodule KafkaexLagExporter.MixProject do
       {:plug_cowboy, "~> 2.6.1"},
       {:credo, "~> 1.7.5", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.0", only: [:dev], runtime: false},
-      {:mox, "~> 1.1", only: :test},
+      {:patch, "~> 0.13.0", only: :test},
       {:brod, "~> 3.17.0"},
       {:prom_ex, "~> 1.8.0"},
       {:telemetry, "~> 1.2"}

mix.lock

@@ -16,10 +16,10 @@
   "kafka_protocol": {:hex, :kafka_protocol, "4.1.5", "d15e64994a8ca99716ab47db4132614359ac1bfa56d6c5b4341fdc1aa4041518", [:rebar3], [{:crc32cer, "0.1.8", [hex: :crc32cer, repo: "hexpm", optional: false]}], "hexpm", "c956c9357fef493b7072a35d0c3e2be02aa5186c804a412d29e62423bb15e5d9"},
   "mime": {:hex, :mime, "2.0.5", "dc34c8efd439abe6ae0343edbb8556f4d63f178594894720607772a041b04b02", [:mix], [], "hexpm", "da0d64a365c45bc9935cc5c8a7fc5e49a0e0f9932a761c55d6c52b142780a05c"},
   "mint": {:hex, :mint, "1.5.2", "4805e059f96028948870d23d7783613b7e6b0e2fb4e98d720383852a760067fd", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:hpax, "~> 0.1.1", [hex: :hpax, repo: "hexpm", optional: false]}], "hexpm", "d77d9e9ce4eb35941907f1d3df38d8f750c357865353e21d335bdcdf6d892a02"},
-  "mox": {:hex, :mox, "1.1.0", "0f5e399649ce9ab7602f72e718305c0f9cdc351190f72844599545e4996af73c", [:mix], [], "hexpm", "d44474c50be02d5b72131070281a5d3895c0e7a95c780e90bc0cfe712f633a13"},
   "nimble_options": {:hex, :nimble_options, "1.1.0", "3b31a57ede9cb1502071fade751ab0c7b8dbe75a9a4c2b5bbb0943a690b63172", [:mix], [], "hexpm", "8bbbb3941af3ca9acc7835f5655ea062111c9c27bcac53e004460dfd19008a99"},
   "nimble_pool": {:hex, :nimble_pool, "1.0.0", "5eb82705d138f4dd4423f69ceb19ac667b3b492ae570c9f5c900bb3d2f50a847", [:mix], [], "hexpm", "80be3b882d2d351882256087078e1b1952a28bf98d0a287be87e4a24a710b67a"},
   "octo_fetch": {:hex, :octo_fetch, "0.4.0", "074b5ecbc08be10b05b27e9db08bc20a3060142769436242702931c418695b19", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~> 1.1", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm", "cf8be6f40cd519d7000bb4e84adcf661c32e59369ca2827c4e20042eda7a7fc6"},
+  "patch": {:hex, :patch, "0.13.0", "da48728f9086a835956200a671210fe88f67ff48bb1f92626989886493ac2081", [:mix], [], "hexpm", "d65a840d485dfa05bf6673269b56680e7537a05050684e713de125a351b28112"},
   "phoenix": {:hex, :phoenix, "1.6.16", "e5bdd18c7a06da5852a25c7befb72246de4ddc289182285f8685a40b7b5f5451", [:mix], [{:castore, ">= 0.0.0", [hex: :castore, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.0", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 1.0 or ~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: false]}, {:plug, "~> 1.10", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.2", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "e15989ff34f670a96b95ef6d1d25bad0d9c50df5df40b671d8f4a669e050ac39"},
   "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.1.3", "3168d78ba41835aecad272d5e8cd51aa87a7ac9eb836eabc42f6e57538e3731d", [:mix], [], "hexpm", "bba06bc1dcfd8cb086759f0edc94a8ba2bc8896d5331a1e2c2902bf8e36ee502"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},

test/consumer_offset_fetcher_test.exs

@@ -0,0 +1,47 @@
+defmodule KafkaexLagExporter.ConsumerOffsetFetcher.Test do
+  use ExUnit.Case, async: true
+  use Patch
+
+  @test_consumer_group_name1 "test_consumer_1"
+  @test_consumer_group_name2 "test_consumer_2"
+  @test_lags [{0, 23}, {1, 42}, {2, 666}]
+
+  setup do
+    patch(
+      KafkaexLagExporter.KafkaUtils,
+      :get_consumer_group_names,
+      fn _ -> [@test_consumer_group_name1, @test_consumer_group_name2] end
+    )
+
+    patch(KafkaexLagExporter.KafkaUtils, :lag, fn _, _, _ -> @test_lags end)
+
+    patch(
+      KafkaexLagExporter.KafkaUtils,
+      :topic_names_for_consumer_groups,
+      fn _, _, _ ->
+        [
+          {@test_consumer_group_name1, ["test_topic_1", "test_topic_2"]},
+          {@test_consumer_group_name2, ["test_topic_3"]}
+        ]
+      end
+    )
+
+    :ok
+  end
+
+  test "should return the calculated lags" do
+    test_endpoint = {"test endpoint", 666}
+
+    %{sum: sum, lags: lags} = KafkaexLagExporter.ConsumerOffsetFetcher.get(test_endpoint)
+
+    assert sum == [
+             {@test_consumer_group_name1, 1462},
+             {@test_consumer_group_name2, 731}
+           ]
+
+    assert lags == [
+             {@test_consumer_group_name1, @test_lags ++ @test_lags},
+             {@test_consumer_group_name2, @test_lags}
+           ]
+  end
+end

test/kafkaex_lag_exporter_test.exs

@@ -1,8 +0,0 @@
-defmodule KafkaexLagExporterTest do
-  use ExUnit.Case
-  doctest KafkaexLagExporter
-
-  test "greets the world" do
-    assert KafkaexLagExporter.hello() == :world
-  end
-end

test/kafkaex_lag_exporter_web/views/error_view_test.exs

@@ -1,17 +0,0 @@
-defmodule KafkaexLagExporterWeb.ErrorViewTest do
-  use KafkaexLagExporterWeb.ConnCase, async: true
-
-  # Bring render/3 and render_to_string/3 for testing custom views
-  import Phoenix.View
-
-  test "renders 404.json" do
-    assert render(KafkaexLagExporterWeb.ErrorView, "404.json", []) == %{
-             errors: %{detail: "Not Found"}
-           }
-  end
-
-  test "renders 500.json" do
-    assert render(KafkaexLagExporterWeb.ErrorView, "500.json", []) ==
-             %{errors: %{detail: "Internal Server Error"}}
-  end
-end

test/support/channel_case.ex

@@ -1,34 +0,0 @@
-defmodule KafkaexLagExporterWeb.ChannelCase do
-  @moduledoc """
-  This module defines the test case to be used by
-  channel tests.
-
-  Such tests rely on `Phoenix.ChannelTest` and also
-  import other functionality to make it easier
-  to build common data structures and query the data layer.
-
-  Finally, if the test case interacts with the database,
-  we enable the SQL sandbox, so changes done to the database
-  are reverted at the end of every test. If you are using
-  PostgreSQL, you can even run database tests asynchronously
-  by setting `use KafkaexLagExporterWeb.ChannelCase, async: true`, although
-  this option is not recommended for other databases.
-  """
-
-  use ExUnit.CaseTemplate
-
-  using do
-    quote do
-      # Import conveniences for testing with channels
-      import Phoenix.ChannelTest
-      import KafkaexLagExporterWeb.ChannelCase
-
-      # The default endpoint for testing
-      @endpoint KafkaexLagExporterWeb.Endpoint
-    end
-  end
-
-  setup _tags do
-    :ok
-  end
-end

test/support/conn_case.ex

@@ -1,37 +0,0 @@
-defmodule KafkaexLagExporterWeb.ConnCase do
-  @moduledoc """
-  This module defines the test case to be used by
-  tests that require setting up a connection.
-
-  Such tests rely on `Phoenix.ConnTest` and also
-  import other functionality to make it easier
-  to build common data structures and query the data layer.
-
-  Finally, if the test case interacts with the database,
-  we enable the SQL sandbox, so changes done to the database
-  are reverted at the end of every test. If you are using
-  PostgreSQL, you can even run database tests asynchronously
-  by setting `use KafkaexLagExporterWeb.ConnCase, async: true`, although
-  this option is not recommended for other databases.
-  """
-
-  use ExUnit.CaseTemplate
-
-  using do
-    quote do
-      # Import conveniences for testing with connections
-      import Plug.Conn
-      import Phoenix.ConnTest
-      import KafkaexLagExporterWeb.ConnCase
-
-      alias KafkaexLagExporterWeb.Router.Helpers, as: Routes
-
-      # The default endpoint for testing
-      @endpoint KafkaexLagExporterWeb.Endpoint
-    end
-  end
-
-  setup _tags do
-    {:ok, conn: Phoenix.ConnTest.build_conn()}
-  end
-end

test/test_helper.exs

@@ -1,2 +1 @@
-Application.ensure_all_started(:mox)
 ExUnit.start()