Add new/1 to Redactor

Closes #151

Author: AndrewDryga

lib/logger_json/formatter.ex

@@ -8,7 +8,14 @@ defmodule LoggerJSON.Formatter do
 
   @type encoder_opts :: JSON.encoder() | [Jason.encode_opt()] | term()
 
-  @callback new(opts) :: {module, :logger.formatter_config()}
+  @doc """
+  Creates a new configuration for the formatter.
+  """
+  @callback new(opts) :: {module, term()}
+
+  @doc """
+  Formats a log event.
+  """
   @callback format(event :: :logger.log_event(), opts :: opts()) :: iodata()
 
   @encoder Application.compile_env(:logger_json, :encoder, Jason)

lib/logger_json/redactor.ex

@@ -6,10 +6,18 @@ defmodule LoggerJSON.Redactor do
   For more information about encoding and redacting see `LoggerJSON.Formatter.RedactorEncoder.encode/2`.
   """
 
+  @doc """
+  Creates a new redactor.
+  """
+  @callback new(opts :: term()) :: {module(), term()}
+
   @doc """
   Takes a key and a value and returns a redacted value.
 
   This callback will be applied on key-value pairs, like elements of structs, maps or keyword lists.
   """
   @callback redact(key :: String.t(), value :: term(), opts :: term()) :: term()
+
+  # TODO: Make it required in a future version
+  @optional_callbacks new: 1
 end

lib/logger_json/redactors/redact_keys.ex

@@ -8,7 +8,7 @@ defmodule LoggerJSON.Redactors.RedactKeys do
     formatter:
       LoggerJSON.Formatters.Basic.new(
         redactors: [
-          {LoggerJSON.Redactors.RedactKeys, ["password"]}
+          LoggerJSON.Redactors.RedactKeys.new(["password"])
         ]
       )
   ```
@@ -18,6 +18,12 @@ defmodule LoggerJSON.Redactors.RedactKeys do
 
   @behaviour LoggerJSON.Redactor
 
+  @impl LoggerJSON.Redactor
+  def new(keys) do
+    {__MODULE__, keys}
+  end
+
+  @impl LoggerJSON.Redactor
   def redact(key, value, keys) do
     if key in keys do
       "[REDACTED]"

test/logger_json/formatter/redactor_encoder_test.exs

@@ -8,7 +8,7 @@ defmodule LoggerJSON.Formatter.RedactorEncoderTest do
   defmodule PasswordStruct, do: defstruct(password: "foo")
 
   @encoder LoggerJSON.Formatter.encoder()
-  @redactors [{LoggerJSON.Redactors.RedactKeys, ["password"]}]
+  @redactors [LoggerJSON.Redactors.RedactKeys.new(["password"])]
 
   describe "encode/2" do
     test "allows nils" do