Setup Dialyxir and Credo code analyzers:

- Refactor codebase according to analyzers

.credo.exs

@@ -0,0 +1,15 @@
+%{
+  configs: [
+    %{
+      name: "default",
+      files: %{
+        included: ["lib/", "test/", "config/"],
+        excluded: []
+      },
+      checks: [
+        {Credo.Check.Refactor.MapInto, false},
+        {Credo.Check.Warning.LazyLogging, false}
+      ]
+    }
+  ]
+}

Makefile

@@ -1,16 +1,17 @@
-.PHONY: all build clean install start test
+.PHONY: all build clean install lint start test
 
-build: install test clean
+build: install lint test clean
 	docker build -t shortnr:latest .
 
 clean:
-	mix clean --deps
+	mix clean
 
 install:
 	mix deps.get
 
-install-prod:
-	mix deps.get --only prod
+lint:
+	mix dialyzer
+	mix credo --strict
 
 start:
 	iex -S mix run --no-halt

config/config.exs

@@ -16,3 +16,9 @@ config :logger, :console,
        :prod -> :info
        _ -> :debug
      end).(Mix.env())
+
+config :credo,
+  checks: [
+    {Credo.Check.Refactor.MapInto, false},
+    {Credo.Check.Warning.LazyLogging, false}
+  ]

lib/router.ex

@@ -1,10 +1,14 @@
 defmodule Shortnr.Router do
+  @moduledoc """
+  This module contains the Router for the Shortnr application. Do not import, other than
+  Application entry.
+  """
   use Plug.ErrorHandler
   use Plug.Router
 
   require Logger
 
-  alias Shortnr.Transport.{Text, HTTP}
+  alias Shortnr.Transport.{HTTP, Text}
   alias Shortnr.URL
 
   plug(Plug.Logger, log: :debug)

lib/shortnr.ex

@@ -1,6 +1,6 @@
 defmodule Shortnr do
   @moduledoc """
-  Documentation for Shortnr.
+  The Shortnr application entry point. Check README for usage documenation.
   """
 
   use Application

lib/transport/http.ex

@@ -1,8 +1,13 @@
 defmodule Shortnr.Transport.HTTP do
+  @moduledoc """
+  This module contains functions that can be used to handle HTTP requests and send responses, by
+  manipulating Plug.Conn.
+  """
+
   import Plug.Conn
 
-  @type ok_error :: {:ok, term(), Plug.Conn.t()} | error()
   @type error :: {:error, {atom(), String.t()}, Plug.Conn.t()}
+  @type ok_error :: {:ok, term(), Plug.Conn.t()} | error()
 
   @spec handle(ok_error(), (... -> ok_error())) :: ok_error()
   def handle(error = {:error, _sub_error, _conn}, _func), do: error

lib/transport/json.ex

@@ -1,28 +0,0 @@
-defmodule Shortnr.Transport.Json do
-  import Plug.Conn
-  alias Shortnr.Transport.HTTP
-
-  @spec decode_request(Plug.Conn.t(), module()) :: HTTP.ok_error()
-  def decode_request(conn, struct_module) do
-    {:ok, body, conn} = read_body(conn)
-    {:ok, params} = Jason.decode(body)
-
-    params_list =
-      params
-      |> Map.to_list()
-      |> Enum.map(fn {key, value} -> {String.to_atom(key), value} end)
-
-    {:ok, struct(struct_module, params_list), conn}
-  end
-
-  @spec encode_response(HTTP.ok_error()) :: HTTP.ok_error()
-  def encode_response({:error, {status, response}, conn}) do
-    {:ok, json_body} = Jason.encode(%{data: response})
-    {:error, {status, json_body}, conn}
-  end
-
-  def encode_response({:ok, response, conn}) do
-    {:ok, json_body} = Jason.encode(%{data: response})
-    {:ok, json_body, conn}
-  end
-end

lib/transport/text.ex

@@ -1,4 +1,8 @@
 defmodule Shortnr.Transport.Text do
+  @moduledoc """
+  This modules contains functions to decode and encode text formatted http requests and responses.
+  """
+
   import Plug.Conn
   alias Shortnr.Transport.HTTP
   alias Shortnr.URL

lib/transport/transport.ex

@@ -1,4 +1,7 @@
 defmodule Shortnr.Transport do
+  @moduledoc """
+  This module houses generic Transport types.
+  """
   @type error :: {:error, {atom(), String.t()}}
   @type ok_error :: {:ok, term()} | error()
 end

lib/url/repo/ets.ex

@@ -1,4 +1,8 @@
 defmodule Shortnr.URL.Repo.ETS do
+  @moduledoc """
+  This module is an implemention of the Repo behaviour using the Erlang ETS library.
+  """
+
   @behaviour Shortnr.URL.Repo
 
   @impl true
@@ -16,7 +20,7 @@ defmodule Shortnr.URL.Repo.ETS do
   end
 
   @impl true
-  def list() do
+  def list do
     resp = ets().select(:urls, [{:"$1", [], [:"$1"]}])
     {:ok, resp |> Enum.map(&elem(&1, 1))}
   end

lib/url/repo/repo.ex

@@ -1,6 +1,11 @@
 defmodule Shortnr.URL.Repo do
-  alias Shortnr.URL
+  @moduledoc """
+  This module defines the Repo behaviour for the URL service. All Repos must implement this
+  entire behaviour.
+  """
+
   alias Shortnr.Transport
+  alias Shortnr.URL
 
   @callback put(URL.t()) :: :ok | Transport.error()
   @callback get(String.t()) :: {:ok, URL.t()} | Transport.error()

lib/url/url.ex

@@ -1,6 +1,9 @@
 defmodule Shortnr.URL do
+  @moduledoc """
+  This module represents both the URL data object, in the form of a struct, and the URL business
+  domain service.
+  """
   alias Shortnr.Transport
-  alias Shortnr.URL
   alias Shortnr.URL.Util
 
   defstruct id: "",
@@ -17,7 +20,7 @@ defmodule Shortnr.URL do
 
   @spec create(String.t(), module()) :: {:ok, String.t()} | Transport.error()
   def create(url, repo) do
-    url_struct = %URL{id: Util.gen_id(), url: URI.parse(url)}
+    url_struct = %__MODULE__{id: Util.gen_id(), url: URI.parse(url)}
 
     {:ok, extant_url} = repo.get(url_struct.id)
 
@@ -29,17 +32,17 @@ defmodule Shortnr.URL do
     end
   end
 
-  @spec get(String.t(), module()) :: {:ok, URL.t()} | Transport.error()
+  @spec get(String.t(), module()) :: {:ok, t()} | Transport.error()
   def get(key, repo) do
     {:ok, _} = repo.get(key)
   end
 
-  @spec list(module()) :: {:ok, list(URL.t())} | Transport.error()
+  @spec list(module()) :: {:ok, list(t())} | Transport.error()
   def list(repo) do
     {:ok, _} = repo.list
   end
 
-  @spec delete(String.t(), module()) :: {:ok, :ignore} | Tranpsport.error()
+  @spec delete(String.t(), module()) :: {:ok, String.t()} | Transport.error()
   def delete(key, repo) do
     :ok = repo.delete(key)
     {:ok, "Success"}

lib/url/util.ex

@@ -1,4 +1,7 @@
 defmodule Shortnr.URL.Util do
+  @moduledoc """
+  URL module utility functions.
+  """
   @id_chars String.codepoints("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXWYZ0123456789")
   @spec gen_id() :: String.t()
   def gen_id do

mix.exs

@@ -24,7 +24,9 @@ defmodule Shortnr.MixProject do
     [
       {:plug_cowboy, "~> 2.0"},
       {:elixir_uuid, "~> 1.2"},
-      {:jason, "~> 1.1"}
+      {:jason, "~> 1.1"},
+      {:dialyxir, "~> 0.5.1", only: [:dev], runtime: false},
+      {:credo, "~> 1.1.5", only: [:dev, :test], runtime: false}
       # {:dep_from_hexpm, "~> 0.3.0"},
       # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
     ]

mix.lock

@@ -1,6 +1,9 @@
 %{
+  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm"},
   "cowboy": {:hex, :cowboy, "2.7.0", "91ed100138a764355f43316b1d23d7ff6bdb0de4ea618cb5d8677c93a7a2f115", [:rebar3], [{:cowlib, "~> 2.8.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "2.8.0", "fd0ff1787db84ac415b8211573e9a30a3ebe71b5cbff7f720089972b2319c8a4", [:rebar3], [], "hexpm"},
+  "credo": {:hex, :credo, "1.1.5", "caec7a3cadd2e58609d7ee25b3931b129e739e070539ad1a0cd7efeeb47014f4", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "0.5.1", "b331b091720fd93e878137add264bac4f644e1ddae07a70bf7062c7862c4b952", [:mix], [], "hexpm"},
   "elixir_uuid": {:hex, :elixir_uuid, "1.2.1", "dce506597acb7e6b0daeaff52ff6a9043f5919a4c3315abb4143f0b00378c097", [:mix], [], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},