surgeventures/surgex

if Code.ensure_loaded?(Plug) do
  defmodule Surgex.Sentry do
    @moduledoc """
    Extensions to the official Sentry package.

    **NOTE: Deprecated in favor of Elixir 1.9 runtime configuration.**
    """

    alias Mix.Project

    @doc """
    Patches Sentry environment name and release version from env vars.

    By default, Sentry package only allows to fetch DSN from env var. This function extends that
    with environment name and release version set on runtime, thus enabling deployments on Heroku
    where application slug is compiled without final env vars.

    ## Examples

    In order to execute this extension on application start, set an appropriate config key:

        config :surgex,
          sentry_patch_enabled: true

    """
    def init do
      if Application.get_env(:surgex, :sentry_patch_enabled, false), do: do_init()
    end

    defp do_init do
      require Logger

      env = get_env()
      release = get_release()

      Logger.info(fn ->
        "Patching Sentry config (environment: #{inspect(env)}, release: #{inspect(release)})"
      end)

      :ok =
        Application.put_all_env(
          sentry: [
            release: release,
            environment_name: env,
            included_environments: [env]
          ]
        )
    end

    defp get_env do
      case Application.get_env(:surgex, :sentry_environment, :mix_env) do
        :mix_env ->
          Mix.env()

        value ->
          Confix.parse(value)
      end
    end

    defp get_release do
      case Application.get_env(:surgex, :sentry_release, :mix_version) do
        :mix_version ->
          Project.config()[:version]

        value ->
          Confix.parse(value)
      end
    end

    @scrubbed_param_keys Application.compile_env(:surgex, :sentry_scrubbed_param_keys, ~w{password})
    @scrubbed_value Application.compile_env(:surgex, :sentry_scrubbed_value, "[Filtered]")

    @doc """
    Deeply scrubs params, obfuscating those with blacklisted names.

    By default, Sentry package only offers flat scrubbing of params. This won't work with nested
    params or JSON objects, so here's deep recursive equivalent of such scrubber.

    ## Examples

    In order to use this extension, pass `Surgex.Sentry.scrub_params/1` to `Sentry.Plug` like this:

        use Sentry.Plug, body_scrubber: &Surgex.Sentry.scrub_params/1

    """
    def scrub_params(%Plug.Conn{params: params}), do: scrub_map(params)

    defp scrub_map(map = %{}) do
      map
      |> Enum.map(&scrub_map_item/1)
      |> Map.new()
    end

    defp scrub_list(list), do: Enum.map(list, &scrub_value/1)

    defp scrub_map_item({key, _value}) when key in @scrubbed_param_keys, do: {key, @scrubbed_value}
    defp scrub_map_item({key, value}), do: {key, scrub_value(value)}

    defp scrub_value(value) when is_map(value), do: scrub_map(value)
    defp scrub_value(value) when is_list(value), do: scrub_list(value)
    defp scrub_value(value), do: value
  end
end