Allow Logger middleware to configured at runtime

lib/tesla/middleware/logger.ex

@@ -53,6 +53,7 @@ defmodule Tesla.Middleware.Logger do
   ## Options
   - `:log_level` - custom function for calculating log level (see below)
   - `:filter_headers` - sanitizes sensitive headers before logging in debug mode (see below)
+  - `:debug` - show detailed request/response logging
 
   ## Custom log format
 
@@ -106,6 +107,23 @@ defmodule Tesla.Middleware.Logger do
   # config/dev.local.exs
   config :tesla, Tesla.Middleware.Logger, debug: false
   ```
+
+  This config will be fetched at compile-time.
+
+  In order to be able to set `:debug` at runtime we can
+  pass it as a option to the middleware at runtime.
+
+  ```elixir
+  def client do
+    middleware = [
+      # ...
+      {Tesla.Middleware.Logger, debug: false}
+    ]
+
+    Tesla.client(middleware)
+  end
+  ```
+
   ### Filter headers
 
   To sanitize sensitive headers such as `authorization` in
@@ -133,20 +151,23 @@ defmodule Tesla.Middleware.Logger do
   @impl Tesla.Middleware
   def call(env, next, opts) do
     {time, response} = :timer.tc(Tesla, :run, [env, next])
-    level = log_level(response, opts)
+
+    config = Keyword.merge(@config, opts)
+
+    level = log_level(response, config)
     Logger.log(level, fn -> Formatter.format(env, response, time, @format) end)
 
-    if Keyword.get(@config, :debug, true) do
-      Logger.debug(fn -> debug(env, response, opts) end)
+    if Keyword.get(config, :debug, true) do
+      Logger.debug(fn -> debug(env, response, config) end)
     end
 
     response
   end
 
   defp log_level({:error, _}, _), do: :error
 
-  defp log_level({:ok, env}, opts) do
-    case Keyword.get(opts, :log_level) do
+  defp log_level({:ok, env}, config) do
+    case Keyword.get(config, :log_level) do
       nil ->
         default_log_level(env)
 
@@ -175,28 +196,28 @@ defmodule Tesla.Middleware.Logger do
   @debug_no_body "(no body)"
   @debug_stream "[Elixir.Stream]"
 
-  defp debug(request, {:ok, response}, opts) do
+  defp debug(request, {:ok, response}, config) do
     [
       "\n>>> REQUEST >>>\n",
       debug_query(request.query),
       ?\n,
-      debug_headers(request.headers, opts),
+      debug_headers(request.headers, config),
       ?\n,
       debug_body(request.body),
       ?\n,
       "\n<<< RESPONSE <<<\n",
-      debug_headers(response.headers, opts),
+      debug_headers(response.headers, config),
       ?\n,
       debug_body(response.body)
     ]
   end
 
-  defp debug(request, {:error, error}, opts) do
+  defp debug(request, {:error, error}, config) do
     [
       "\n>>> REQUEST >>>\n",
       debug_query(request.query),
       ?\n,
-      debug_headers(request.headers, opts),
+      debug_headers(request.headers, config),
       ?\n,
       debug_body(request.body),
       ?\n,
@@ -213,10 +234,10 @@ defmodule Tesla.Middleware.Logger do
     |> Enum.map(fn {k, v} -> ["Query: ", to_string(k), ": ", to_string(v), ?\n] end)
   end
 
-  defp debug_headers([], _opts), do: @debug_no_headers
+  defp debug_headers([], _config), do: @debug_no_headers
 
-  defp debug_headers(headers, opts) do
-    filtered = Keyword.get(opts, :filter_headers, [])
+  defp debug_headers(headers, config) do
+    filtered = Keyword.get(config, :filter_headers, [])
 
     Enum.map(headers, fn {k, v} ->
       v = if k in filtered, do: "[FILTERED]", else: v

test/tesla/middleware/logger_test.exs

@@ -93,6 +93,16 @@ defmodule Tesla.Middleware.LoggerTest do
       assert log =~ "/ok -> 200"
       assert log =~ "Stream"
     end
+
+    test "config at runtime" do
+      client =
+        Tesla.client([{Tesla.Middleware.Logger, debug: false}], fn env ->
+          {:ok, %{env | body: "response"}}
+        end)
+
+      log = capture_log(fn -> Tesla.get(client, "/ok", query: %{"test" => "true"}) end)
+      refute log =~ "Query: test: true"
+    end
   end
 
   describe "Debug mode with custom structs" do