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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   defstruct pool_size: 0,
  13             active: 0,
  14             idle: 0,
  15             memory_used: 0,
  16             healthy: true
  17
  18   @type t :: %__MODULE__{
  19           pool_size: non_neg_integer(),
  20           active: non_neg_integer(),
  21           idle: non_neg_integer(),
  22           memory_used: number(),
  23           healthy: boolean()
  24         }
  25
  26   @spec system_info() :: t()
  27   def system_info do
  28     %Healthcheck{
  29       memory_used: Float.round(:erlang.memory(:total) / 1024 / 1024, 2)
  30     }
  31     |> assign_db_info()
  32     |> check_health()
  33   end
  34
  35   defp assign_db_info(healthcheck) do
  36     database = Pleroma.Config.get([Repo, :database])
  37
  38     query =
  39       "select state, count(pid) from pg_stat_activity where datname = '#{database}' group by state;"
  40
  41     result = Repo.query!(query)
  42     pool_size = Pleroma.Config.get([Repo, :pool_size])
  43
  44     db_info =
  45       Enum.reduce(result.rows, %{active: 0, idle: 0}, fn [state, cnt], states ->
  46         if state == "active" do
  47           Map.put(states, :active, states.active + cnt)
  48         else
  49           Map.put(states, :idle, states.idle + cnt)
  50         end
  51       end)
  52       |> Map.put(:pool_size, pool_size)
  53
  54     Map.merge(healthcheck, db_info)
  55   end
  56
  57   @spec check_health(Healthcheck.t()) :: Healthcheck.t()
  58   def check_health(%{pool_size: pool_size, active: active} = check)
  59       when active >= pool_size do
  60     %{check | healthy: false}
  61   end
  62
  63   def check_health(check), do: check
  64 end