lecture 06

lectures/06/counter/lib/counter_web/controllers/counter_controller.ex

@@ -0,0 +1,18 @@
+defmodule CounterWeb.CounterController do
+  use CounterWeb, :controller
+
+  def new(conn, %{"name" => name}) do
+	Counter.DynamicSupervisor.start_worker(name)
+	render(conn, :new)
+  end
+
+  def value(conn, %{"name" => name}) do
+	value = Counter.Worker.value(name)
+	render(conn, :value, value: value)
+  end
+
+  def inc(conn, %{"name" => name, "amt" => amt}) when is_integer(amt) do
+	Counter.Worker.inc(name, amt)
+	render(conn, :inc)
+  end
+end

lectures/06/counter/lib/counter_web/controllers/counter_json.ex

@@ -0,0 +1,13 @@
+defmodule CounterWeb.CounterJSON do
+  def value(assigns) do
+	%{value: assigns.value}
+  end
+
+  def new(_assigns) do
+	%{status: "ok"}
+  end
+
+  def inc(_assigns) do
+	%{status: "ok"}
+  end
+end

lectures/06/counter/lib/counter_web/controllers/error_json.ex

@@ -0,0 +1,21 @@
+defmodule CounterWeb.ErrorJSON do
+  @moduledoc """
+  This module is invoked by your endpoint in case of errors on JSON requests.
+
+  See config/config.exs.
+  """
+
+  # If you want to customize a particular status code,
+  # you may add your own clauses, such as:
+  #
+  # def render("500.json", _assigns) do
+  #   %{errors: %{detail: "Internal Server Error"}}
+  # end
+
+  # By default, Phoenix returns the status message from
+  # the template name. For example, "404.json" becomes
+  # "Not Found".
+  def render(template, _assigns) do
+    %{errors: %{detail: Phoenix.Controller.status_message_from_template(template)}}
+  end
+end

lectures/06/counter/lib/counter_web/endpoint.ex

@@ -0,0 +1,52 @@
+defmodule CounterWeb.Endpoint do
+  use Phoenix.Endpoint, otp_app: :counter
+
+  # The session will be stored in the cookie and signed,
+  # this means its contents can be read but not tampered with.
+  # Set :encryption_salt if you would also like to encrypt it.
+  @session_options [
+    store: :cookie,
+    key: "_counter_key",
+    signing_salt: "u8wt1XSs",
+    same_site: "Lax"
+  ]
+
+  socket "/live", Phoenix.LiveView.Socket,
+    websocket: [connect_info: [session: @session_options]],
+    longpoll: [connect_info: [session: @session_options]]
+
+  # Serve at "/" the static files from "priv/static" directory.
+  #
+  # When code reloading is disabled (e.g., in production),
+  # the `gzip` option is enabled to serve compressed
+  # static files generated by running `phx.digest`.
+  plug Plug.Static,
+    at: "/",
+    from: :counter,
+    gzip: not code_reloading?,
+    only: CounterWeb.static_paths(),
+    raise_on_missing_only: code_reloading?
+
+  # Code reloading can be explicitly enabled under the
+  # :code_reloader configuration of your endpoint.
+  if code_reloading? do
+    plug Phoenix.CodeReloader
+  end
+
+  plug Phoenix.LiveDashboard.RequestLogger,
+    param_key: "request_logger",
+    cookie_key: "request_logger"
+
+  plug Plug.RequestId
+  plug Plug.Telemetry, event_prefix: [:phoenix, :endpoint]
+
+  plug Plug.Parsers,
+    parsers: [:urlencoded, :multipart, :json],
+    pass: ["*/*"],
+    json_decoder: Phoenix.json_library()
+
+  plug Plug.MethodOverride
+  plug Plug.Head
+  plug Plug.Session, @session_options
+  plug CounterWeb.Router
+end

lectures/06/counter/lib/counter_web/gettext.ex

@@ -0,0 +1,25 @@
+defmodule CounterWeb.Gettext do
+  @moduledoc """
+  A module providing Internationalization with a gettext-based API.
+
+  By using [Gettext](https://gettext.hexdocs.pm), your module compiles translations
+  that you can use in your application. To use this Gettext backend module,
+  call `use Gettext` and pass it as an option:
+
+      use Gettext, backend: CounterWeb.Gettext
+
+      # Simple translation
+      gettext("Here is the string to translate")
+
+      # Plural translation
+      ngettext("Here is the string to translate",
+               "Here are the strings to translate",
+               3)
+
+      # Domain-based translation
+      dgettext("errors", "Here is the error message to translate")
+
+  See the [Gettext Docs](https://gettext.hexdocs.pm) for detailed usage.
+  """
+  use Gettext.Backend, otp_app: :counter
+end

lectures/06/counter/lib/counter_web/router.ex

@@ -0,0 +1,31 @@
+defmodule CounterWeb.Router do
+  use CounterWeb, :router
+
+  pipeline :api do
+	plug :accepts, ["json"]
+  end
+
+  scope "/api", CounterWeb do
+	pipe_through :api
+
+	post "/counter/new/:name", CounterController, :new
+	get "/counter/value/:name", CounterController, :value
+	post "/counter/inc/:name", CounterController, :inc
+  end
+
+  # Enable LiveDashboard in development
+  if Application.compile_env(:counter, :dev_routes) do
+	# If you want to use the LiveDashboard in production, you should put
+	# it behind authentication and allow only admins to access it.
+	# If your application does not have an admins-only section yet,
+	# you can use Plug.BasicAuth to set up some basic authentication
+	# as long as you are also using SSL (which you should anyway).
+	import Phoenix.LiveDashboard.Router
+
+	scope "/dev" do
+	  pipe_through [:fetch_session, :protect_from_forgery]
+
+	  live_dashboard "/dashboard", metrics: CounterWeb.Telemetry
+	end
+  end
+end

lectures/06/counter/lib/counter_web/telemetry.ex

@@ -0,0 +1,70 @@
+defmodule CounterWeb.Telemetry do
+  use Supervisor
+  import Telemetry.Metrics
+
+  def start_link(arg) do
+    Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
+  end
+
+  @impl true
+  def init(_arg) do
+    children = [
+      # Telemetry poller will execute the given period measurements
+      # every 10_000ms. Learn more here: https://telemetry-metrics.hexdocs.pm
+      {:telemetry_poller, measurements: periodic_measurements(), period: 10_000}
+      # Add reporters as children of your supervision tree.
+      # {Telemetry.Metrics.ConsoleReporter, metrics: metrics()}
+    ]
+
+    Supervisor.init(children, strategy: :one_for_one)
+  end
+
+  def metrics do
+    [
+      # Phoenix Metrics
+      summary("phoenix.endpoint.start.system_time",
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.endpoint.stop.duration",
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.router_dispatch.start.system_time",
+        tags: [:route],
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.router_dispatch.exception.duration",
+        tags: [:route],
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.router_dispatch.stop.duration",
+        tags: [:route],
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.socket_connected.duration",
+        unit: {:native, :millisecond}
+      ),
+      sum("phoenix.socket_drain.count"),
+      summary("phoenix.channel_joined.duration",
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.channel_handled_in.duration",
+        tags: [:event],
+        unit: {:native, :millisecond}
+      ),
+
+      # VM Metrics
+      summary("vm.memory.total", unit: {:byte, :kilobyte}),
+      summary("vm.total_run_queue_lengths.total"),
+      summary("vm.total_run_queue_lengths.cpu"),
+      summary("vm.total_run_queue_lengths.io")
+    ]
+  end
+
+  defp periodic_measurements do
+    [
+      # A module, function and arguments to be invoked periodically.
+      # This function must call :telemetry.execute/3 and a metric must be added above.
+      # {CounterWeb, :count_users, []}
+    ]
+  end
+end