Make function in Mailings.SenderAdapters.SES for caching keys public

This allows for less code duplication in the SES adapter and webhook tests
and ensures well-defined behavior in the tests.

lib/keila/mailings/sender_adapters/ses.ex

@@ -92,15 +92,27 @@ defmodule Keila.Mailings.SenderAdapters.SES do
     end
   end
 
-  defp put_cached_key(url, key) do
+  @doc """
+  Put the key from the given URL in an in-memory cache.
+
+  This function is public to allow testing this module.
+  """
+  @spec put_cached_key(String.t(), :public_key.public_key()) :: :ok
+  def put_cached_key(url, key) do
     if is_nil(Process.whereis(__MODULE__.Cache)) do
       Agent.start_link(fn -> %{} end, name: __MODULE__.Cache)
     end
 
     Agent.update(__MODULE__.Cache, &Map.put(&1, url, key))
   end
 
-  defp extract_key(pem_file) do
+  @doc """
+  Extract the public key from a PEM file.
+
+  This function is public to allow testing this module.
+  """
+  @spec extract_key(Path.t()) :: :public_key.public_key()
+  def extract_key(pem_file) do
     pem_file
     |> :public_key.pem_decode()
     |> then(fn [{_, cert, _}] -> :public_key.pkix_decode_cert(cert, :otp) end)

test/keila/mailings/ses/mailings_senders_ses_test.exs

@@ -2,6 +2,24 @@ defmodule Keila.Mailings.SendersSESTest do
   use Keila.DataCase, async: true
   alias Keila.Mailings
 
+  @aws_key "SimpleNotificationService-7ff5318490ec183fbaddaa2a969abfda.pem"
+
+  setup do
+    # Add AWS key to cache because otherwise test data might go stale when
+    # AWS cycles keys
+    Path.join(:code.priv_dir(:keila), "vendor/aws/#{@aws_key}")
+    |> File.read!()
+    |> Keila.Mailings.SenderAdapters.SES.extract_key()
+    |> then(fn key ->
+      Keila.Mailings.SenderAdapters.SES.put_cached_key(
+        "https://sns.eu-central-1.amazonaws.com/#{@aws_key}",
+        key
+      )
+    end)
+
+    :ok
+  end
+
   @tag :mailings_ses
   test "validate signature from SES/SNS notification" do
     notification =

test/keila_web/controllers/ses_webhook_controller_test.exs

@@ -11,16 +11,21 @@ defmodule KeilaWeb.SESWebhookControllerTest do
 
     # Add AWS key to cache because otherwise test data might go stale when
     # AWS cycles keys
-    File.read!(Path.join(:code.priv_dir(:keila), "vendor/aws/#{@aws_key}"))
-    |> extract_key()
+    Path.join(:code.priv_dir(:keila), "vendor/aws/#{@aws_key}")
+    |> File.read!()
+    |> Keila.Mailings.SenderAdapters.SES.extract_key()
     |> then(fn key ->
-      put_cached_key("https://sns.eu-central-1.amazonaws.com/#{@aws_key}", key)
+      Keila.Mailings.SenderAdapters.SES.put_cached_key(
+        "https://sns.eu-central-1.amazonaws.com/#{@aws_key}",
+        key
+      )
     end)
 
     %{project: project}
   end
 
-  @tag :ses_webhook_controller
+  :ses_webhook_controller
+
   test "handle bounces from SES", %{conn: conn, project: project} do
     contact = insert!(:contact, project_id: project.id)
     campaign = insert!(:mailings_campaign, project_id: project.id)
@@ -59,26 +64,4 @@ defmodule KeilaWeb.SESWebhookControllerTest do
 
     assert 200 == conn.status
   end
-
-  # Functions taken from Keila.Mailings.SenderAdapters.SES
-  defp put_cached_key(url, key) do
-    if is_nil(Process.whereis(Keila.Mailings.SenderAdapters.SES.Cache)) do
-      Agent.start_link(fn -> %{} end, name: Keila.Mailings.SenderAdapters.SES.Cache)
-    end
-
-    Agent.update(Keila.Mailings.SenderAdapters.SES.Cache, &Map.put(&1, url, key))
-  end
-
-  defp extract_key(pem_file) do
-    pem_file
-    |> :public_key.pem_decode()
-    |> then(fn [{_, cert, _}] -> :public_key.pkix_decode_cert(cert, :otp) end)
-    |> fetch_record_field(:OTPTBSCertificate)
-    |> fetch_record_field(:OTPSubjectPublicKeyInfo)
-    |> fetch_record_field(:RSAPublicKey)
-  end
-
-  defp fetch_record_field(record, key) do
-    record |> Tuple.to_list() |> Enum.find(fn el -> is_tuple(el) && elem(el, 0) == key end)
-  end
 end