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
70 lines
2 KiB
Elixir
70 lines
2 KiB
Elixir
defmodule ProxmoxAgent.Diagnostics do
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@moduledoc """
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Optional diagnostic dump of external commands and outgoing samples.
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Controlled by `:dump_dir` in the application env. When unset or nil,
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`log_command/4` and `log_sample/2` are no-ops and incur no I/O.
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When set, they cast to `ProxmoxAgent.Diagnostics.Writer` (if running)
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which serializes appends to `commands.log` and `samples.log`.
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"""
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require Logger
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@type command_result ::
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{:ok, String.t()}
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| {:error, term()}
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@spec configure(String.t() | nil) :: :ok
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def configure(nil), do: disable()
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def configure(""), do: disable()
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def configure(dir) when is_binary(dir) do
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case File.mkdir_p(dir) do
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:ok ->
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Application.put_env(:agent, :dump_dir, dir)
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Logger.info("diagnostics: enabled, writing to #{dir}")
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:ok
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{:error, reason} ->
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Logger.warning("diagnostics: mkdir_p #{dir} failed (#{inspect(reason)}); dumping disabled")
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disable()
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end
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end
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@spec enabled?() :: boolean()
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def enabled?, do: not is_nil(Application.get_env(:agent, :dump_dir))
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@spec dump_dir() :: String.t() | nil
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def dump_dir, do: Application.get_env(:agent, :dump_dir)
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@spec log_command(String.t(), [String.t()], command_result(), non_neg_integer()) :: :ok
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def log_command(cmd, args, result, duration_us) do
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cast({:command, cmd, args, result, duration_us})
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end
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@spec log_sample(String.t(), map()) :: :ok
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def log_sample(kind, payload) when is_binary(kind) and is_map(payload) do
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cast({:sample, kind, payload})
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end
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@spec log_read(Path.t(), command_result(), non_neg_integer()) :: :ok
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def log_read(path, result, duration_us) do
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log_command("cat", [to_string(path)], result, duration_us)
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end
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defp disable do
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Application.delete_env(:agent, :dump_dir)
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:ok
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end
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defp cast(msg) do
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if enabled?() do
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case Process.whereis(ProxmoxAgent.Diagnostics.Writer) do
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nil -> :ok
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pid -> GenServer.cast(pid, msg)
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end
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end
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:ok
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end
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end
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