feat(agent): slipstream reporter — join, push, auto-reconnect

agent/lib/proxmox_agent/reporter.ex

@@ -0,0 +1,75 @@
+defmodule ProxmoxAgent.Reporter do
+  @moduledoc """
+  Maintains a persistent Phoenix Channel connection to the server, joins
+  `host:<host_id>`, and pushes metric samples on the configured fast interval.
+  """
+
+  use Slipstream, restart: :permanent
+  require Logger
+
+  alias ProxmoxAgent.Collectors.Host
+
+  def start_link(%ProxmoxAgent.Config{} = cfg) do
+    Slipstream.start_link(__MODULE__, cfg, name: __MODULE__)
+  end
+
+  @impl Slipstream
+  def init(cfg) do
+    socket =
+      new_socket()
+      |> assign(:cfg, cfg)
+      |> assign(:topic, "host:" <> cfg.host_id)
+      |> connect!(uri: cfg.server_url)
+
+    {:ok, socket}
+  end
+
+  @impl Slipstream
+  def handle_connect(socket) do
+    topic = socket.assigns.topic
+    cfg = socket.assigns.cfg
+
+    payload = %{"token" => cfg.token, "agent_version" => ProxmoxAgent.version()}
+    Logger.info("reporter: connected, joining #{topic}")
+    {:ok, join(socket, topic, payload)}
+  end
+
+  @impl Slipstream
+  def handle_join(topic, _reply, socket) do
+    Logger.info("reporter: joined #{topic}")
+    send(self(), :collect_fast)
+    {:ok, socket}
+  end
+
+  @impl Slipstream
+  def handle_info(:collect_fast, socket) do
+    sample = Host.collect()
+    payload = %{collected_at: DateTime.utc_now() |> DateTime.to_iso8601(), data: sample}
+    :ok = push_metric(socket, "metric:fast", payload)
+    Process.send_after(self(), :collect_fast, socket.assigns.cfg.fast_seconds * 1000)
+    {:ok, socket}
+  end
+
+  @impl Slipstream
+  def handle_disconnect(reason, socket) do
+    Logger.warning("reporter: disconnected — #{inspect(reason)}; reconnecting")
+    reconnect(socket)
+  end
+
+  @impl Slipstream
+  def handle_topic_close(topic, reason, socket) do
+    Logger.warning("reporter: topic #{topic} closed: #{inspect(reason)}; rejoining")
+    rejoin(socket, topic)
+  end
+
+  defp push_metric(socket, event, payload) do
+    case push(socket, socket.assigns.topic, event, payload) do
+      {:ok, _ref} ->
+        :ok
+
+      {:error, reason} ->
+        Logger.warning("reporter: push failed: #{inspect(reason)}")
+        :ok
+    end
+  end
+end