Carsten
3367b95b91
Addresses final code review: - Host collector's /proc reads now go through Diagnostics.log_read/3, appearing in commands.log formatted as `$ cat /proc/loadavg` - configure/1 logs an info line on successful enable so the operator has a breadcrumb in the journal - Writer.init/1 documents the deliberate trap_exit omission
98 lines
2.8 KiB
Elixir
98 lines
2.8 KiB
Elixir
defmodule ProxmoxAgent.Diagnostics.Writer do
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@moduledoc """
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Serializes diagnostic dump writes. Owns two append-only file handles
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for commands.log and samples.log under a configured directory.
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Started only when the agent's dump_dir is set. All writes are cast-based
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to keep the caller path free of file I/O latency.
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"""
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use GenServer
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require Logger
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@spec start_link(keyword()) :: GenServer.on_start()
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def start_link(opts) do
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GenServer.start_link(__MODULE__, opts, name: __MODULE__)
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end
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@impl true
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def init(opts) do
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dir = Keyword.fetch!(opts, :dir)
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# No trap_exit: the Writer owns no linked processes other than the supervisor.
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# If you add a linked port/task, restore Process.flag(:trap_exit, true) and
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# add a matching handle_info({:EXIT, _, _}, state) clause.
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with {:ok, commands} <- open(Path.join(dir, "commands.log")),
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{:ok, samples} <- open(Path.join(dir, "samples.log")) do
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{:ok, %{dir: dir, commands: commands, samples: samples}}
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else
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{:error, reason} ->
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{:stop, {:open_failed, reason}}
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end
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end
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@impl true
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def handle_cast({:command, cmd, args, result, duration_us}, state) do
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write(state.commands, format_command(cmd, args, result, duration_us))
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{:noreply, state}
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end
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def handle_cast({:sample, kind, payload}, state) do
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write(state.samples, format_sample(kind, payload))
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{:noreply, state}
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end
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@impl true
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def handle_call(:flush, _from, state) do
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{:reply, :ok, state}
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end
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@impl true
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def terminate(_reason, state) do
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File.close(state.commands)
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File.close(state.samples)
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:ok
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end
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# --- private ----------------------------------------------------------
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defp open(path), do: File.open(path, [:append, :utf8])
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defp write(io, data) do
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case IO.write(io, data) do
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:ok ->
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:ok
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{:error, reason} ->
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Logger.warning("diagnostics writer: write failed (#{inspect(reason)})")
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:ok
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end
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end
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defp format_command(cmd, args, result, duration_us) do
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header = "===== #{now_iso()} =====\n$ #{cmd} #{Enum.join(args, " ")}\n"
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status =
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case result do
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{:ok, body} ->
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"exit=0 duration=#{ms(duration_us)}ms size=#{byte_size(body)}\n\n#{body}\n\n"
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{:error, {:nonzero_exit, code, body}} ->
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"exit=#{code} duration=#{ms(duration_us)}ms size=#{byte_size(body)}\n\n#{body}\n\n"
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{:error, reason} ->
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"error=#{inspect(reason)} duration=#{ms(duration_us)}ms\n\n"
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end
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header <> status
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end
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defp format_sample(kind, payload) do
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body = Jason.encode!(payload, pretty: true)
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"===== #{now_iso()} kind=#{kind} =====\n#{body}\n\n"
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end
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defp now_iso, do: DateTime.utc_now() |> DateTime.to_iso8601()
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defp ms(us) when is_integer(us), do: div(us, 1_000)
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end
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