allow to set json encoder

lib/plug/logger_json.ex

@@ -21,7 +21,13 @@ defmodule Plug.LoggerJSON do
   }
   ```
 
-  To use it, just plug it into the desired module.
+  To use it, set json_encoder parameter in your config:
+
+  ```
+  config :plug_logger_json, json_encoder: Jason
+  ```
+
+  and plug it into the desired module:
   plug Plug.LoggerJSON, log: :debug
   ## Options
   * `:log` - The log level at which this plug should log its request info.
@@ -105,12 +111,11 @@ defmodule Plug.LoggerJSON do
   def log_error(kind, reason, stacktrace) do
     _ =
       Logger.log(:error, fn ->
-        %{
+        encode!(%{
           "log_type" => "error",
           "message" => Exception.format(kind, reason, stacktrace),
           "request_id" => Logger.metadata()[:request_id]
-        }
-        |> Poison.encode!()
+        })
       end)
   end
 
@@ -122,7 +127,7 @@ defmodule Plug.LoggerJSON do
       |> Map.merge(debug_logging(conn, opts))
       |> Map.merge(phoenix_attributes(conn))
       |> Map.merge(extra_attributes(conn, opts))
-      |> Poison.encode!()
+      |> encode!()
     end)
   end
 
@@ -254,4 +259,9 @@ defmodule Plug.LoggerJSON do
     num = Integer.to_string(val)
     :binary.copy("0", count - byte_size(num)) <> num
   end
+
+  def encode!(value) do
+    encoder = Application.get_env(:plug_logger_json, :json_encoder)
+    encoder.encode!(value)
+  end
 end

mix.exs

@@ -15,7 +15,12 @@ defmodule PlugLoggerJson.Mixfile do
       homepage_url: "https://github.com/bleacherreport/plug_logger_json",
       name: "Plug Logger JSON",
       package: package(),
-      preferred_cli_env: [coveralls: :test, "coveralls.detail": :test, "coveralls.post": :test, "coveralls.html": :test],
+      preferred_cli_env: [
+        coveralls: :test,
+        "coveralls.detail": :test,
+        "coveralls.post": :test,
+        "coveralls.html": :test
+      ],
       source_url: "https://github.com/bleacherreport/plug_logger_json",
       start_permanent: Mix.env() == :prod,
       test_coverage: [tool: ExCoveralls],
@@ -35,7 +40,8 @@ defmodule PlugLoggerJson.Mixfile do
       {:ex_doc, "~> 0.19.3", only: [:dev]},
       {:excoveralls, "~> 0.10.5", only: [:test]},
       {:plug, "~> 1.0"},
-      {:poison, "~> 1.5 or ~> 2.0 or ~> 3.0 or ~> 4.0"}
+      {:poison, "~> 1.5 or ~> 2.0 or ~> 3.0 or ~> 4.0", optional: true},
+      {:jason, "~> 1.1", optional: true}
     ]
   end
 

mix.lock

@@ -24,3 +24,4 @@
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
 }
+

test/plug/logger_json_test.exs

@@ -94,6 +94,10 @@ defmodule Plug.LoggerJSONTest do
     {Process.get(:get_log), data}
   end
 
+  setup do
+    Application.put_env(:plug_logger_json, :json_encoder, Jason)
+  end
+
   test "correct output - no params or headers" do
     {_conn, message} =
       conn(:get, "/")