FormatHelper handles missing fields, moved webhook to smallest scope

lib/slack_logger_backend/format_helper.ex

@@ -9,23 +9,17 @@ defmodule SlackLoggerBackend.FormatHelper do
   Formats a log event for Slack.
   """
   def format_event(detail) do
-    fields = [
-      field("Module", detail.module),
-      field("Function", detail.function),
-      field("File", detail.file),
-      field("Line", detail.line),
-      field("Count", detail.count)
-    ]
-
     fields =
-      if Map.has_key?(detail, :application) do
-        [
-          field("Level", detail.level),
-          field("Application", detail.application) | fields
-        ]
-      else
-        [field("Level", detail.level) | fields]
-      end
+      [
+        field("Level", detail, :level),
+        field("Application", detail, :application),
+        field("Module", detail, :module),
+        field("Function", detail, :function),
+        field("File", detail, :file),
+        field("Line", detail, :line),
+        field("Count", detail, :count)
+      ]
+      |> Enum.reject(&is_nil/1)
 
     {:ok, json} =
       %{
@@ -42,11 +36,17 @@ defmodule SlackLoggerBackend.FormatHelper do
     json
   end
 
-  defp field(title, value) do
-    %{
-      title: title,
-      value: value,
-      short: true
-    }
+  defp field(title, map, key) do
+    case map[key] do
+      nil ->
+        nil
+
+      value ->
+        %{
+          title: title,
+          value: value,
+          short: true
+        }
+    end
   end
 end

lib/slack_logger_backend/pool.ex

@@ -5,8 +5,6 @@ defmodule SlackLoggerBackend.Pool do
   use Supervisor
   alias SlackLoggerBackend.PoolWorker
 
-  @env_webhook "SLACK_LOGGER_WEBHOOK_URL"
-
   @doc false
   def start_link(pool_size) do
     Supervisor.start_link(__MODULE__, pool_size, name: __MODULE__)
@@ -40,16 +38,9 @@ defmodule SlackLoggerBackend.Pool do
     :poolboy.transaction(
       :message_pool,
       fn pid ->
-        PoolWorker.post(pid, get_url(), json)
+        PoolWorker.post(pid, json)
       end,
       :infinity
     )
   end
-
-  defp get_url() do
-    case System.get_env(@env_webhook) do
-      nil -> Application.get_env(:slack_logger_backend, :slack_webhook, nil)
-      url -> url
-    end
-  end
 end

lib/slack_logger_backend/pool_worker.ex

@@ -5,6 +5,8 @@ defmodule SlackLoggerBackend.PoolWorker do
 
   use GenServer
 
+  @env_webhook "SLACK_LOGGER_WEBHOOK_URL"
+
   @doc false
   def start_link([]) do
     GenServer.start_link(__MODULE__, [], [])
@@ -16,16 +18,23 @@ defmodule SlackLoggerBackend.PoolWorker do
   end
 
   @doc false
-  def handle_call({:post, url, json}, _from, worker_state) do
-    result = HTTPoison.post(url, json)
+  def handle_call({:post, json}, _from, worker_state) do
+    result = HTTPoison.post(get_url(), json)
     {:reply, result, worker_state}
   end
 
   @doc """
   Gets a message.
   """
-  @spec post(pid, String.t(), String.t()) :: atom
-  def post(pid, url, json) do
-    GenServer.call(pid, {:post, url, json}, :infinity)
+  @spec post(pid, String.t()) :: atom
+  def post(pid, json) do
+    GenServer.call(pid, {:post, json}, :infinity)
+  end
+
+  defp get_url() do
+    case System.get_env(@env_webhook) do
+      nil -> Application.get_env(:slack_logger_backend, :slack_webhook, nil)
+      url -> url
+    end
   end
 end

test/slack_logger_backend/pool_worker_test.exs

@@ -1,27 +1,26 @@
-ExUnit.start
+ExUnit.start()
 
 defmodule SlackLoggerBackend.PoolWorkerTest do
   use ExUnit.Case
   alias SlackLoggerBackend.{PoolWorker}
 
   setup do
-    bypass = Bypass.open
+    bypass = Bypass.open()
     url = "http://localhost:#{bypass.port}/hook"
-    {:ok, %{bypass: bypass, url: url}}
+    Application.put_env(:slack_logger_backend, :slack_webhook, url)
+    {:ok, %{bypass: bypass}}
   end
 
   test "posts the error to the Slack incoming webhook", %{
-    bypass: bypass,
-    url: url
- } do
-    Bypass.expect bypass, fn conn ->
+    bypass: bypass
+  } do
+    Bypass.expect(bypass, fn conn ->
       assert "/hook" == conn.request_path
       assert "POST" == conn.method
       Plug.Conn.resp(conn, 200, "ok")
-    end
+    end)
 
     {:ok, pid} = PoolWorker.start_link([])
-    {:ok, _} = PoolWorker.post(pid, url, "test")
+    {:ok, _} = PoolWorker.post(pid, "test")
   end
-
 end