Add user_id to log.

config/config.exs

@@ -17,7 +17,7 @@ config :hello_phoenix, HelloPhoenix.Endpoint,
 # Configures Elixir's Logger
 config :logger, :console,
   format: "$time $metadata[$level] $message\n",
-  metadata: [:request_id]
+  metadata: [:request_id, :user_id]
 
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.

web/controllers/session_controller.ex

@@ -0,0 +1,19 @@
+defmodule HelloPhoenix.SessionController do
+  use HelloPhoenix.Web, :controller
+  require Logger
+
+  def index(conn, _params) do
+    render conn, "index.html"
+  end
+
+  def create(conn, %{"login" => %{"email" => email, "password" => _}}) do
+    # dummy login
+    user_id = email
+
+    Logger.info("login: user_id=" <> user_id)
+
+    conn
+    |> put_session(:user_id, user_id)
+    |> redirect(to: "/")
+  end
+end

web/plugs/log_user_id.ex

@@ -0,0 +1,13 @@
+defmodule HelloPhoenix.Plugs.LogUserId do
+  import Plug.Conn
+  require Logger
+
+  def init(default), do: default
+
+  def call(conn, _default) do
+    user_id = Plug.Conn.get_session(conn, :user_id)
+    Logger.metadata(user_id: user_id)
+    # IO.puts(user_id)
+    conn
+  end
+end

web/router.ex

@@ -1,7 +1,6 @@
 defmodule HelloPhoenix.Router do
   use HelloPhoenix.Web, :router
 
-
   pipeline :browser do
     plug :accepts, ["html"]
     plug :fetch_session
@@ -10,15 +9,22 @@ defmodule HelloPhoenix.Router do
   end
 
   pipeline :api do
+    plug :fetch_session
+    plug HelloPhoenix.Plugs.LogUserId
     plug :accepts, ["json"]
   end
 
   scope "/", HelloPhoenix do
     pipe_through :browser
 
-    get "/",                 PageController,  :index
-    get "/hello",            HelloController, :index
-    get "/hello/:messenger", HelloController, :show
+    get    "/",                 PageController,    :index
+
+    get    "/hello",            HelloController,   :index
+    get    "/hello/:messenger", HelloController,   :show
+
+    get    "/login",            SessionController, :index
+    post   "/login",            SessionController, :create
+    delete "/login",            SessionController, :delete
 
   end
 

web/templates/session/index.html.eex

@@ -0,0 +1,5 @@
+<%= form_for @conn, session_path(@conn, :create), [name: :login], fn form -> %>
+  <%= text_input form, :email %>
+  <%= password_input form, :password %>
+  <%= submit "Login" %>
+<% end %>

web/views/hello_view.ex

@@ -1,3 +1,3 @@
-defmodule HelloPhoenix.HelloView do
+defmodule HelloPhoenix.SessionView do
   use HelloPhoenix.Web, :view
 end

web/views/session_view.ex

@@ -0,0 +1,3 @@
+defmodule HelloPhoenix.HelloView do
+  use HelloPhoenix.Web, :view
+end