Handle binwrite failures in installer

Since Elixir 1.16, the IO.binwrite/2 function no longer returns an :ok- or :error tuple. Instead, it simply raises an error when it fails. To keep compatibility with previous versions of Elixir, this patch implements binwrite_with_result, which is a delegate of IO.binwrite/2 on versions before 1.16, and a try-catch wrapper for Elixir 1.16 and above. With that function in place, the precious implementation is restored, which prints "Failure!" before the error message in the unlikely event that the write fails. Co-authored-by: Tom de Bruijn <tom@tomdebruijn.com>
appsignal · Jun 26, 2024 · a4095cf · a4095cf
1 parent b65751f
commit a4095cf
Showing 1 changed file with 21 additions and 2 deletions.
diff --git a/lib/mix/tasks/appsignal.install.ex b/lib/mix/tasks/appsignal.install.ex
@@ -183,8 +183,15 @@ defmodule Mix.Tasks.Appsignal.Install do
 
     case File.open(appsignal_config_file_path(), [:write]) do
       {:ok, file} ->
-        IO.binwrite(file, appsignal_config_file_contents(config))
-        IO.puts("Success!")
+        case binwrite_with_result(file, appsignal_config_file_contents(config)) do
+          :ok ->
+            IO.puts("Success!")
+
+          {:error, reason} ->
+            IO.puts("Failure! #{inspect(reason)}")
+            exit(:shutdown)
+        end
+
         File.close(file)
 
       {:error, reason} ->
@@ -193,6 +200,18 @@ defmodule Mix.Tasks.Appsignal.Install do
     end
   end
 
+  if Version.match?(System.version(), ">= 1.16.0") do
+    defp binwrite_with_result(path, contents) do
+      try do
+        IO.binwrite(path, contents)
+      catch
+        {:error, reason} -> {:error, reason}
+      end
+    end
+  else
+    defdelegate binwrite_with_result(path, contents), to: IO, as: :binwrite
+  end
+
   # Link the config/appsignal.exs config file to the config/config.exs file.
   # If already linked, it's ignored.
   defp link_config_file do