Use Application.get_env/3 at runtime

Author: bruce

lib/segment.ex

@@ -155,25 +155,29 @@ defmodule Segment do
           | Segment.Analytics.Alias.t()
           | Segment.Analytics.Group.t()
           | Segment.Analytics.Page.t()
-  require Logger
-  @service Application.get_env(:segment, :sender_impl, Segment.Analytics.Batcher)
 
   @doc """
   Start the configured GenServer for handling Segment events with the Segment HTTP Source API Write Key
 
   By default if nothing is configured it will start `Segment.Analytics.Batcher`
   """
   @spec start_link(String.t()) :: GenServer.on_start()
-  defdelegate start_link(api_key), to: @service
+  def start_link(api_key) do
+    Segment.Config.service().start_link(api_key)
+  end
 
   @doc """
   Start the configured GenServer for handling Segment events with the Segment HTTP Source API Write Key and a custom Tesla Adapter.
 
   By default if nothing is configured it will start `Segment.Analytics.Batcher`
   """
   @spec start_link(String.t(), Telsa.adapter()) :: GenServer.on_start()
-  defdelegate start_link(api_key, adapter), to: @service
+  def start_link(api_key, adapter) do
+    Segment.Config.service().start_link(api_key, adapter)
+  end
 
   @spec child_spec(map()) :: map()
-  defdelegate child_spec(opts), to: @service
+  def child_spec(opts) do
+    Segment.Config.service().child_spec(opts)
+  end
 end

lib/segment/analytics.ex

@@ -12,8 +12,6 @@ defmodule Segment.Analytics do
 
   @type segment_id :: String.t() | integer()
 
-  @service Application.get_env(:segment, :sender_impl, Segment.Analytics.Batcher)
-
   @doc """
     Make a call to Segment with an event. Should be of type `Track, Identify, Screen, Alias, Group or Page`
   """
@@ -165,5 +163,7 @@ defmodule Segment.Analytics do
   end
 
   @spec call(Segment.segment_event()) :: :ok
-  defdelegate call(event), to: @service
+  def call(event) do
+    Segment.Config.service().call(event)
+  end
 end

lib/segment/batcher.ex

@@ -22,9 +22,6 @@ defmodule Segment.Analytics.Batcher do
   use GenServer
   alias Segment.Analytics.{Track, Identify, Screen, Alias, Group, Page}
 
-  @max_batch_size Application.get_env(:segment, :max_batch_size, 100)
-  @batch_every_ms Application.get_env(:segment, :batch_every_ms, 2000)
-
   @doc """
     Start the `Segment.Analytics.Batcher` GenServer with an Segment HTTP Source API Write Key
   """
@@ -96,7 +93,7 @@ defmodule Segment.Analytics.Batcher do
 
   # Helpers
   defp schedule_batch_send do
-    Process.send_after(self(), :process_batch, @batch_every_ms)
+    Process.send_after(self(), :process_batch, Segment.Config.batch_every_ms())
   end
 
   defp enqueue(event) do
@@ -106,13 +103,16 @@ defmodule Segment.Analytics.Batcher do
   defp extract_batch(queue, 0),
     do: {[], queue}
 
-  defp extract_batch(queue, length) when length >= @max_batch_size do
-    :queue.split(@max_batch_size, queue)
-    |> split_result()
-  end
+  defp extract_batch(queue, length) do
+    max_batch_size = Segment.Config.max_batch_size()
 
-  defp extract_batch(queue, length),
-    do: :queue.split(length, queue) |> split_result()
+    if length >= max_batch_size do
+      :queue.split(max_batch_size, queue)
+      |> split_result()
+    else
+      :queue.split(length, queue) |> split_result()
+    end
+  end
 
   defp split_result({q1, q2}), do: {:queue.to_list(q1), q2}
 end

lib/segment/client/http.ex

@@ -41,18 +41,14 @@ defmodule Segment.Http do
   use Retry
 
   @segment_api_url "https://api.segment.io/v1/"
-  @send_to_http Application.get_env(:segment, :send_to_http, true)
-  @retry_attempts Application.get_env(:segment, :retry_attempts, 3)
-  @retry_expiry Application.get_env(:segment, :retry_expiry, 10_000)
-  @retry_start Application.get_env(:segment, :retry_start, 100)
 
   @doc """
     Create a Tesla client with the Segment Source Write API Key
   """
   @spec client(String.t()) :: client()
   def client(api_key) do
     adapter =
-      case @send_to_http do
+      case Segment.Config.send_to_http() do
         true ->
           Application.get_env(:segment, :tesla)[:adapter] ||
             {Tesla.Adapter.Hackney, [recv_timeout: 30_000]}
@@ -89,7 +85,7 @@ defmodule Segment.Http do
   """
   @spec send(String.t(), Segment.segment_event()) :: :ok | :error
   def send(client, event) do
-    case make_request(client, event.type, prepare_events(event), @retry_attempts) do
+    case make_request(client, event.type, prepare_events(event), Segment.Config.retry_attempts()) do
       {:ok, %{status: status}} when status == 200 ->
         :ok
 
@@ -98,7 +94,10 @@ defmodule Segment.Http do
         :error
 
       {:error, err} ->
-        Logger.error("[Segment] Call Failed after #{@retry_attempts} retries. #{inspect(err)}")
+        Logger.error(
+          "[Segment] Call Failed after #{Segment.Config.retry_attempts()} retries. #{inspect(err)}"
+        )
+
         :error
 
       err ->
@@ -120,7 +119,7 @@ defmodule Segment.Http do
       |> add_if(:context, context)
       |> add_if(:integrations, integrations)
 
-    case make_request(client, "batch", data, @retry_attempts) do
+    case make_request(client, "batch", data, Segment.Config.retry_attempts()) do
       {:ok, %{status: status}} when status == 200 ->
         :ok
 
@@ -133,9 +132,9 @@ defmodule Segment.Http do
 
       {:error, err} ->
         Logger.error(
-          "[Segment] Batch call of #{length(events)} events failed after #{@retry_attempts} retries. #{
-            inspect(err)
-          }"
+          "[Segment] Batch call of #{length(events)} events failed after #{
+            Segment.Config.retry_attempts()
+          } retries. #{inspect(err)}"
         )
 
         :error
@@ -147,7 +146,10 @@ defmodule Segment.Http do
   end
 
   defp make_request(client, url, data, retries) when retries > 0 do
-    retry with: linear_backoff(@retry_start, 2) |> cap(@retry_expiry) |> Stream.take(retries) do
+    retry with:
+            linear_backoff(Segment.Config.retry_start(), 2)
+            |> cap(Segment.Config.retry_expiry())
+            |> Stream.take(retries) do
       Tesla.post(client, url, data)
     after
       result -> result

lib/segment/config.ex

@@ -0,0 +1,31 @@
+defmodule Segment.Config do
+  @moduledoc false
+
+  def service do
+    Application.get_env(:segment, :sender_impl, Segment.Analytics.Batcher)
+  end
+
+  def max_batch_size() do
+    Application.get_env(:segment, :max_batch_size, 100)
+  end
+
+  def batch_every_ms() do
+    Application.get_env(:segment, :batch_every_ms, 2000)
+  end
+
+  def send_to_http() do
+    Application.get_env(:segment, :send_to_http, true)
+  end
+
+  def retry_attempts() do
+    Application.get_env(:segment, :retry_attempts, 3)
+  end
+
+  def retry_expiry() do
+    Application.get_env(:segment, :retry_expiry, 10_000)
+  end
+
+  def retry_start() do
+    Application.get_env(:segment, :retry_start, 100)
+  end
+end