ecto_logger_json

defmodule Ecto.LoggerJSON do
  @moduledoc """
  Keep in sync with https://github.com/elixir-ecto/ecto/blob/master/lib/ecto/log_entry.ex

  Struct used for logging entries.
  It is composed of the following fields:
    * query - the query as string or a function that when invoked resolves to string;
    * source - the query data source;
    * params - the query parameters;
    * result - the query result as an `:ok` or `:error` tuple;
    * query_time - the time spent executing the query in native units;
    * decode_time - the time spent decoding the result in native units (it may be nil);
    * queue_time - the time spent to check the connection out in native units (it may be nil);
    * connection_pid - the connection process that executed the query;
    * ansi_color - the color that chould be used when logging the entry.
  Notice all times are stored in native unit. You must convert them to
  the proper unit by using `System.convert_time_unit/3` before logging.
  """

  require Logger

  @doc """
  Overwritten to use JSON
  Logs the given entry in debug mode.
  The logger call will be removed at compile time if
  `compile_time_purge_level` is set to higher than debug.
  """
  @spec log(%{}) :: %{}
  def log(entry) do
    _ = Logger.debug(fn ->
      %{query_time: query_time, decode_time: decode_time, queue_time: queue_time, query: query} = entry
      [query_time, decode_time, queue_time] =
        [query_time, decode_time, queue_time]
        |> Enum.map(&format_time/1)

      %{
        "decode_time" => decode_time,
        "duration"    => Float.round(query_time + decode_time + queue_time, 3),
        "log_type"    => "persistence",
        "request_id"  => Logger.metadata[:request_id],
        "query"       => query,
        "query_time"  => query_time,
        "queue_time"  => queue_time
      }
      |> Poison.encode!
    end)
  entry
  end

  @doc """
  Overwritten to use JSON
  Logs the given entry in the given level.
  The logger call won't be removed at compile time as
  custom level is given.
  """
  @spec log(%{}, atom) :: %{}
  def log(entry, level) do
    _ = Logger.log(level, fn ->
      %{query_time: query_time, decode_time: decode_time, queue_time: queue_time, query: query} = entry
      [query_time, decode_time, queue_time] =
        [query_time, decode_time, queue_time]
        |> Enum.map(&format_time/1)

      %{
        "decode_time" => decode_time,
        "duration"    => Float.round(query_time + decode_time + queue_time, 3),
        "log_type"    => "persistence",
        "request_id"  => Logger.metadata[:request_id],
        "query"       => query,
        "query_time"  => query_time,
        "queue_time"  => queue_time
      }
      |> Poison.encode!
    end)
    entry
  end

  ## Helpers

  defp format_time(nil), do: 0.0
  defp format_time(time) do
    ms = System.convert_time_unit(time, :native, :micro_seconds) / 1000
    Float.round(ms, 3)
  end
end