Harden OpenAI api layer

- Support rate limiting
- Add proper error handling (don't rely on exceptions)

Closes #147

config/config.exs

@@ -72,7 +72,9 @@ config :music_library, BraveSearch,
   user_agent: user_agent,
   api_cooldown: 1000
 
-config :music_library, OpenAI, api_key: "change me"
+config :music_library, OpenAI,
+  api_key: "change me",
+  api_cooldown: 250
 
 # Configure esbuild (the version is required)
 config :esbuild,

config/test.exs

@@ -96,7 +96,8 @@ config :music_library, OpenAI,
   req_options: [
     plug: {Req.Test, OpenAI.API},
     max_retries: 0
-  ]
+  ],
+  api_cooldown: 0
 
 config :phoenix_test, :endpoint, MusicLibraryWeb.Endpoint
 

lib/open_ai/api.ex

@@ -3,8 +3,7 @@ defmodule OpenAI.API do
 
   @spec gpt(OpenAI.Completion.t(), OpenAI.Config.t()) :: {:ok, map()} | {:error, term()}
   def gpt(completion, config) do
-    resp =
-      config
+    case config
          |> new_request()
          |> Req.merge(
            url: "/v1/chat/completions",
@@ -17,13 +16,16 @@ defmodule OpenAI.API do
              temperature: completion.temperature
            }
          )
-      |> Req.post!()
+         |> Req.post() do
+      {:ok, %{status: status, body: body}} when status in 200..299 ->
+        content = get_in(body, ["choices", Access.at(0), "message", "content"])
+        JSON.decode(content)
 
-    if resp.status in 200..299 do
-      content = get_in(resp.body, ["choices", Access.at(0), "message", "content"])
-      {:ok, JSON.decode!(content)}
-    else
-      {:error, resp.body}
+      {:ok, %{body: body}} ->
+        {:error, "OpenAI API error: #{inspect(body)}"}
+
+      {:error, exception} ->
+        {:error, "Connection error: #{Exception.message(exception)}"}
     end
   end
 
@@ -92,6 +94,7 @@ defmodule OpenAI.API do
       auth: {:bearer, config.api_key}
     )
     |> Req.Request.merge_options(config.req_options)
+    |> Req.RateLimiter.attach(name: :open_ai, cooldown: config.api_cooldown)
     |> Req.Request.append_request_steps(log_attempt: &log_attempt/1)
     |> Req.Request.append_response_steps(log_error: &log_error/1)
   end

lib/open_ai/config.ex

@@ -1,12 +1,14 @@
 defmodule OpenAI.Config do
   @type t :: %__MODULE__{
           api_key: String.t(),
-          req_options: Keyword.t()
+          req_options: Keyword.t(),
+          api_cooldown: non_neg_integer()
         }
 
   @enforce_keys [:api_key]
   defstruct api_key: "",
-            req_options: []
+            req_options: [],
+            api_cooldown: 500
 
   @schema NimbleOptions.new!(
             api_key: [
@@ -17,6 +19,11 @@ defmodule OpenAI.Config do
               type: :keyword_list,
               required: false,
               default: []
+            ],
+            api_cooldown: [
+              type: :integer,
+              required: false,
+              default: 500
             ]
           )