Add ability to handle malformed Check files

lib/wanda/catalog.ex

@@ -32,14 +32,21 @@ defmodule Wanda.Catalog do
   """
   @spec get_check(String.t()) :: {:ok, Check.t()} | {:error, any}
   def get_check(check_id) do
-    case get_catalog_path()
-         |> Path.join("#{check_id}.yaml")
-         |> YamlElixir.read_from_file() do
-      {:ok, file_content} ->
-        {:ok, map_check(file_content)}
+    with path <- Path.join(get_catalog_path(), "#{check_id}.yaml"),
+         {:ok, file_content} <- YamlElixir.read_from_file(path),
+         {:ok, check} <-
+           map_check(file_content) do
+      {:ok, check}
+    else
+      {:error, :malformed_error} = error ->
+        Logger.error(
+          "Check with ID #{check_id} is malformed. Check if all the required fields are present."
+        )
+
+        error
 
       {:error, reason} = error ->
-        Logger.error("Error getting file with ID #{check_id}: #{inspect(reason)}")
+        Logger.error("Error getting Check with ID #{check_id}: #{inspect(reason)}")
         error
     end
   end
@@ -72,17 +79,22 @@ defmodule Wanda.Catalog do
            "expectations" => expectations
          } = check
        ) do
-    %Check{
-      id: id,
-      name: name,
-      group: group,
-      description: description,
-      remediation: remediation,
-      severity: map_severity(check),
-      facts: Enum.map(facts, &map_fact/1),
-      values: map_values(check),
-      expectations: Enum.map(expectations, &map_expectation/1)
-    }
+    {:ok,
+     %Check{
+       id: id,
+       name: name,
+       group: group,
+       description: description,
+       remediation: remediation,
+       severity: map_severity(check),
+       facts: Enum.map(facts, &map_fact/1),
+       values: map_values(check),
+       expectations: Enum.map(expectations, &map_expectation/1)
+     }}
+  end
+
+  defp map_check(_) do
+    {:error, :malformed_check}
   end
 
   defp map_severity(%{"severity" => "critical"}), do: :critical

test/catalog_test.exs

@@ -15,17 +15,18 @@ defmodule Wanda.CatalogTest do
     test "should return the whole catalog" do
       catalog_path = Application.fetch_env!(:wanda, Wanda.Catalog)[:catalog_path]
 
-      files =
+      valid_files =
         catalog_path
         |> File.ls!()
         |> Enum.sort()
+        |> Enum.filter(fn file -> file != "malformed_check.yaml" end)
 
       catalog = Catalog.get_catalog()
-      assert length(files) == length(catalog)
+      assert length(valid_files) == length(catalog)
 
       Enum.with_index(catalog, fn check, index ->
         file_name =
-          files
+          valid_files
           |> Enum.at(index)
           |> Path.basename(".yaml")
 
@@ -108,6 +109,10 @@ defmodule Wanda.CatalogTest do
       assert {:error, _} = Catalog.get_check("non_existent_check")
     end
 
+    test "should return an error for malformed check" do
+      assert {:error, :malformed_check} = Catalog.get_check("malformed_check")
+    end
+
     test "should load multiple checks" do
       assert [%Check{id: "expect_check"}, %Check{id: "expect_same_check"}] =
                Catalog.get_checks(["expect_check", "non_existent_check", "expect_same_check"])

test/fixtures/catalog/malformed_check.yaml

@@ -0,0 +1,11 @@
+id: malformed_check
+name: Malformed check
+group: Test
+description: |
+  A malformed check
+remediation: |
+  ## Remediation
+  Remediation text
+expectations:
+  - name: some_expectation
+    expect_same: facts.jedi