who_need_help/lib/who_need_help/tracking_presence_cleanup.ex

60 lines
1.6 KiB
Elixir

defmodule WhoNeedHelp.TrackingPresenceCleanup do
@moduledoc false
use GenServer
alias WhoNeedHelp.Tracking
alias WhoNeedHelpWeb.Presence
def start_link(options), do: GenServer.start_link(__MODULE__, options, name: __MODULE__)
def maybe_stop(key, assignment_id, user_id, tracking_session_id) do
GenServer.cast(
__MODULE__,
{:maybe_stop, key, assignment_id, user_id, tracking_session_id}
)
end
@impl GenServer
def init(_options) do
# Phoenix 1.8.9's locked browser client can wait up to 5 seconds between
# reconnect attempts. Waiting for that same interval prevents a serving
# node replacement from being mistaken for the user closing the last tab.
grace_ms =
Application.fetch_env!(:who_need_help, :tracking_presence_cleanup_grace_ms)
if not is_integer(grace_ms) or grace_ms < 0 do
raise ArgumentError,
":tracking_presence_cleanup_grace_ms must be a non-negative integer"
end
{:ok, %{grace_ms: grace_ms}}
end
@impl GenServer
def handle_cast(
{:maybe_stop, key, assignment_id, user_id, tracking_session_id},
state
) do
Process.send_after(
self(),
{:maybe_stop_after_grace, key, assignment_id, user_id, tracking_session_id},
state.grace_ms
)
{:noreply, state}
end
@impl GenServer
def handle_info(
{:maybe_stop_after_grace, key, assignment_id, user_id, tracking_session_id},
state
) do
if Presence.get_by_key(Presence.tracking_topic(), key) == [] do
Tracking.stop_browser_session(assignment_id, user_id, tracking_session_id)
end
{:noreply, state}
end
end