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   1 # Pleroma: A lightweight social networking server
   2 # Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
   3 # SPDX-License-Identifier: AGPL-3.0-only
   4
   5 defmodule Pleroma.Healthcheck do
   6   @moduledoc """
   7   Module collects metrics about app and assign healthy status.
   8   """
   9   alias Pleroma.Healthcheck
  10   alias Pleroma.Repo
  11
  12   @derive Jason.Encoder
  13   defstruct pool_size: 0,
  14             active: 0,
  15             idle: 0,
  16             memory_used: 0,
  17             healthy: true
  18
  19   @type t :: %__MODULE__{
  20           pool_size: non_neg_integer(),
  21           active: non_neg_integer(),
  22           idle: non_neg_integer(),
  23           memory_used: number(),
  24           healthy: boolean()
  25         }
  26
  27   @spec system_info() :: t()
  28   def system_info do
  29     %Healthcheck{
  30       memory_used: Float.round(:erlang.memory(:total) / 1024 / 1024, 2)
  31     }
  32     |> assign_db_info()
  33     |> check_health()
  34   end
  35
  36   defp assign_db_info(healthcheck) do
  37     database = Pleroma.Config.get([Repo, :database])
  38
  39     query =
  40       "select state, count(pid) from pg_stat_activity where datname = '#{database}' group by state;"
  41
  42     result = Repo.query!(query)
  43     pool_size = Pleroma.Config.get([Repo, :pool_size])
  44
  45     db_info =
  46       Enum.reduce(result.rows, %{active: 0, idle: 0}, fn [state, cnt], states ->
  47         if state == "active" do
  48           Map.put(states, :active, states.active + cnt)
  49         else
  50           Map.put(states, :idle, states.idle + cnt)
  51         end
  52       end)
  53       |> Map.put(:pool_size, pool_size)
  54
  55     Map.merge(healthcheck, db_info)
  56   end
  57
  58   @spec check_health(Healthcheck.t()) :: Healthcheck.t()
  59   def check_health(%{pool_size: pool_size, active: active} = check)
  60       when active >= pool_size do
  61     %{check | healthy: false}
  62   end
  63
  64   def check_health(check), do: check
  65 end