proxMon/agent/lib/proxmox_agent/diagnostics/writer.ex

95 lines
2.5 KiB
Elixir

defmodule ProxmoxAgent.Diagnostics.Writer do
@moduledoc """
Serializes diagnostic dump writes. Owns two append-only file handles
for commands.log and samples.log under a configured directory.
Started only when the agent's dump_dir is set. All writes are cast-based
to keep the caller path free of file I/O latency.
"""
use GenServer
require Logger
@spec start_link(keyword()) :: GenServer.on_start()
def start_link(opts) do
GenServer.start_link(__MODULE__, opts, name: __MODULE__)
end
@impl true
def init(opts) do
dir = Keyword.fetch!(opts, :dir)
with {:ok, commands} <- open(Path.join(dir, "commands.log")),
{:ok, samples} <- open(Path.join(dir, "samples.log")) do
{:ok, %{dir: dir, commands: commands, samples: samples}}
else
{:error, reason} ->
{:stop, {:open_failed, reason}}
end
end
@impl true
def handle_cast({:command, cmd, args, result, duration_us}, state) do
write(state.commands, format_command(cmd, args, result, duration_us))
{:noreply, state}
end
def handle_cast({:sample, kind, payload}, state) do
write(state.samples, format_sample(kind, payload))
{:noreply, state}
end
@impl true
def handle_call(:flush, _from, state) do
{:reply, :ok, state}
end
@impl true
def terminate(_reason, state) do
File.close(state.commands)
File.close(state.samples)
:ok
end
# --- private ----------------------------------------------------------
defp open(path), do: File.open(path, [:append, :utf8])
defp write(io, data) do
case IO.write(io, data) do
:ok ->
:ok
{:error, reason} ->
Logger.warning("diagnostics writer: write failed (#{inspect(reason)})")
:ok
end
end
defp format_command(cmd, args, result, duration_us) do
header = "===== #{now_iso()} =====\n$ #{cmd} #{Enum.join(args, " ")}\n"
status =
case result do
{:ok, body} ->
"exit=0 duration=#{ms(duration_us)}ms size=#{byte_size(body)}\n\n#{body}\n\n"
{:error, {:nonzero_exit, code, body}} ->
"exit=#{code} duration=#{ms(duration_us)}ms size=#{byte_size(body)}\n\n#{body}\n\n"
{:error, reason} ->
"error=#{inspect(reason)} duration=#{ms(duration_us)}ms\n\n"
end
header <> status
end
defp format_sample(kind, payload) do
body = Jason.encode!(payload, pretty: true)
"===== #{now_iso()} kind=#{kind} =====\n#{body}\n\n"
end
defp now_iso, do: DateTime.utc_now() |> DateTime.to_iso8601()
defp ms(us) when is_integer(us), do: div(us, 1_000)
end