agala v3.0.0 Agala

Link to this section Summary

Functions

Gets the value, stored under the given key across bot’s supervisor lifetime. Can be usefull to reveal some state across restarting handlers, responsers and receivers

This method is used to show bot’s receive <-> handle load

TODO: Docs and examples

TODO: Docs and examples

Sets given value under given key across bot’s supervisor lifetime. Can be usefull to store some state across restarting handlers, responsers and receivers

Called when an application is started

Link to this section Functions

Link to this function get(bot_params, key)

Gets the value, stored under the given key across bot’s supervisor lifetime. Can be usefull to reveal some state across restarting handlers, responsers and receivers.

Link to this function get_load(bot_name)
get_load(bot_name :: Agala.Bot.t()) :: {:ok, integer()} | {:error, any()}

This method is used to show bot’s receive <-> handle load.

  • Active Receivers can use this information in order to stop retrieving new updates from third-parties.
  • Passive Receivers can use this information to stop serving for a moment until load will not decrease.

Example:

# For active receivers

def get_updates() do
  # check if service is overloaded
  case Agala.Backbone.Foo.get_load(MyApp.MyBot) do
    {:ok, overload} when overload > 1000 ->
      # This server is overloaded
      # waiting a bit, to let handlers deal with overload
      :timer.sleep(10_000)
      download_updates()
    {:ok, normal} ->
      # We should not wait - load is normal
      download_updates()
  end
end

# For passive receivers
def call(conn, opts) do
  # check if service is overloaded
  case Agala.Backbone.Foo.get_load(MyApp.MyBot) do
    {:ok, overload} when overload > 1000 ->
      # This server is overloaded
      # Stop serving
      send_500_http_error(conn)
    {:ok, normal} ->
      # We should not wait - load is normal
      proceed_update(conn)
  end
end

TODO: Docs and examples

Link to this function push(bot_name, cid, value)

TODO: Docs and examples

Link to this function set(bot_params, key, value)

Sets given value under given key across bot’s supervisor lifetime. Can be usefull to store some state across restarting handlers, responsers and receivers.

Link to this function start(start_type, start_args)

Called when an application is started.

This function is called when an application is started using Application.start/2 (and functions on top of that, such as Application.ensure_started/2). This function should start the top-level process of the application (which should be the top supervisor of the application’s supervision tree if the application follows the OTP design principles around supervision).

start_type defines how the application is started:

  • :normal - used if the startup is a normal startup or if the application is distributed and is started on the current node because of a failover from another node and the application specification key :start_phases is :undefined.
  • {:takeover, node} - used if the application is distributed and is started on the current node because of a failover on the node node.
  • {:failover, node} - used if the application is distributed and is started on the current node because of a failover on node node, and the application specification key :start_phases is not :undefined.

start_args are the arguments passed to the application in the :mod specification key (e.g., mod: {MyApp, [:my_args]}).

This function should either return {:ok, pid} or {:ok, pid, state} if startup is successful. pid should be the PID of the top supervisor. state can be an arbitrary term, and if omitted will default to []; if the application is later stopped, state is passed to the stop/1 callback (see the documentation for the c:stop/1 callback for more information).

use Application provides no default implementation for the start/2 callback.

Callback implementation for Application.start/2.