Enable heartbeat on application start

Author: aaronrenner

freezer_eye/config/test.exs

@@ -1 +1,9 @@
 use Mix.Config
+
+config :freezer_eye,
+  enable_heartbeat_on_startup: true
+
+config :fe_reporting, :adafruit_io,
+  username: "foo",
+  secret_key: "bar",
+  heartbeat_feed: "test-feed"

freezer_eye/lib/freezer_eye/config.ex

@@ -5,10 +5,11 @@ defmodule FreezerEye.Config do
 
   @behaviour __MODULE__.Impl
 
-  defstruct [:heartbeat_interval]
+  defstruct [:heartbeat_interval, :enable_heartbeat_on_startup?]
 
   @type t :: %__MODULE__{
-          heartbeat_interval: pos_integer()
+          heartbeat_interval: pos_integer(),
+          enable_heartbeat_on_startup?: boolean
         }
 
   @impl true

freezer_eye/lib/freezer_eye/config/env_impl.ex

@@ -9,7 +9,9 @@ defmodule FreezerEye.Config.EnvImpl do
   @spec fetch!() :: Config.t() | none
   def fetch! do
     %Config{
-      heartbeat_interval: Application.fetch_env!(:freezer_eye, :heartbeat_interval)
+      heartbeat_interval: Application.fetch_env!(:freezer_eye, :heartbeat_interval),
+      enable_heartbeat_on_startup?:
+        Application.get_env(:freezer_eye, :enable_heartbeat_on_startup, true)
     }
   end
 end

freezer_eye/lib/freezer_eye/default_impl/manager.ex

@@ -0,0 +1,27 @@
+defmodule FreezerEye.DefaultImpl.Manager do
+  @moduledoc false
+  use GenServer
+
+  alias FreezerEye.Config
+  alias FreezerEye.DefaultImpl.Heartbeats
+
+  def start_link(opts) when is_list(opts) do
+    GenServer.start_link(__MODULE__, opts)
+  end
+
+  @impl true
+  def init(_init_opts) do
+    {:ok, [], {:continue, :start}}
+  end
+
+  @impl true
+  def handle_continue(:start, state) do
+    %Config{enable_heartbeat_on_startup?: enable_heartbeat_on_startup?} = Config.fetch!()
+
+    if enable_heartbeat_on_startup? do
+      Heartbeats.start_default()
+    end
+
+    {:noreply, state}
+  end
+end

freezer_eye/lib/freezer_eye/default_impl/supervisor.ex

@@ -3,6 +3,7 @@ defmodule FreezerEye.DefaultImpl.Supervisor do
   use Supervisor
 
   alias FreezerEye.DefaultImpl.Heartbeats
+  alias FreezerEye.DefaultImpl.Manager
 
   def start_link(opts) when is_list(opts) do
     Supervisor.start_link(__MODULE__, opts, name: __MODULE__)
@@ -11,7 +12,8 @@ defmodule FreezerEye.DefaultImpl.Supervisor do
   @impl true
   def init(_init_opts) do
     children = [
-      Heartbeats
+      Heartbeats,
+      Manager
     ]
 
     Supervisor.init(children, strategy: :one_for_one)

freezer_eye/test/freezer_eye/config/env_impl_test.exs

@@ -11,7 +11,8 @@ defmodule FreezerEye.Config.EnvImplTest do
 
   property "fetch!/0 returns a config struct with the proper values" do
     config_value_generators = [
-      heartbeat_interval: positive_integer()
+      heartbeat_interval: positive_integer(),
+      enable_heartbeat_on_startup: boolean()
     ]
 
     check all config <-
@@ -28,7 +29,9 @@ defmodule FreezerEye.Config.EnvImplTest do
 
       if has_required_keys?(config, [:heartbeat_interval]) do
         assert %Config{
-                 heartbeat_interval: Keyword.fetch!(config, :heartbeat_interval)
+                 heartbeat_interval: Keyword.fetch!(config, :heartbeat_interval),
+                 enable_heartbeat_on_startup?:
+                   Keyword.get(config, :enable_heartbeat_on_startup, true)
                } == EnvImpl.fetch!()
       else
         assert_raise ArgumentError, fn ->

integration_tester/config/config.exs

@@ -2,29 +2,4 @@
 # and its dependencies with the aid of the Mix.Config module.
 use Mix.Config
 
-# This configuration is loaded before any dependency and is restricted
-# to this project. If another project depends on this project, this
-# file won't be loaded nor affect the parent project. For this reason,
-# if you want to provide default values for your application for
-# third-party users, it should be done in your "mix.exs" file.
-
-# You can configure your application as:
-#
-#     config :integration_tester, key: :value
-#
-# and access this configuration in your application as:
-#
-#     Application.get_env(:integration_tester, :key)
-#
-# You can also configure a third-party app:
-#
-#     config :logger, level: :info
-#
-
-# It is also possible to import configuration files, relative to this
-# directory. For example, you can emulate configuration per environment
-# by uncommenting the line below and defining dev.exs, test.exs and such.
-# Configuration from the imported file will override the ones defined
-# here (which is why it is important to import them last).
-#
-#     import_config "#{Mix.env()}.exs"
+import_config "#{Mix.env()}.exs"

integration_tester/config/dev.exs

@@ -0,0 +1 @@
+use Mix.Config

integration_tester/config/prod.exs

@@ -0,0 +1 @@
+use Mix.Config

integration_tester/config/test.exs

@@ -0,0 +1,5 @@
+use Mix.Config
+
+config :freezer_eye,
+  heartbeat_interval: 200,
+  enable_heartbeat_on_startup: false