feat(agent): supervisor boots reporter when config is present

agent/config/config.exs

@@ -0,0 +1,7 @@
+import Config
+
+config :logger, :default_formatter, format: "$time [$level] $message\n"
+
+if File.exists?(Path.join([__DIR__, "#{config_env()}.exs"])) do
+  import_config "#{config_env()}.exs"
+end

agent/config/runtime.exs

@@ -0,0 +1,5 @@
+import Config
+
+if path = System.get_env("AGENT_CONFIG") do
+  config :agent, :config_path, path
+end

agent/lib/proxmox_agent/application.ex

@@ -1,20 +1,32 @@
 defmodule ProxmoxAgent.Application do
-  # See https://hexdocs.pm/elixir/Application.html
-  # for more information on OTP Applications
   @moduledoc false
-
   use Application
+  require Logger
 
   @impl true
   def start(_type, _args) do
-    children = [
-      # Starts a worker by calling: ProxmoxAgent.Worker.start_link(arg)
-      # {ProxmoxAgent.Worker, arg}
-    ]
+    children =
+      case load_config() do
+        {:ok, cfg} ->
+          Logger.info("agent: starting with host_id=#{cfg.host_id}")
+          [{ProxmoxAgent.Reporter, cfg}]
 
-    # See https://hexdocs.pm/elixir/Supervisor.html
-    # for other strategies and supported options
-    opts = [strategy: :one_for_one, name: ProxmoxAgent.Supervisor]
-    Supervisor.start_link(children, opts)
+        {:error, reason} ->
+          Logger.error("agent: no config loaded (#{inspect(reason)}); running in idle mode")
+          []
+      end
+
+    Supervisor.start_link(children, strategy: :one_for_one, name: ProxmoxAgent.Supervisor)
+  end
+
+  defp load_config do
+    path =
+      System.get_env("AGENT_CONFIG") ||
+        Application.get_env(:agent, :config_path, "/etc/proxmox-monitor/agent.toml")
+
+    case File.exists?(path) do
+      true -> ProxmoxAgent.Config.load(path)
+      false -> {:error, {:file_missing, path}}
+    end
   end
 end