@spec arguments(
  %Edeliver.Relup.Instructions{
    changed_modules: term(),
    down_instructions: term(),
    down_version: term(),
    up_instructions: term(),
    up_version: term()
  },
  Edeliver.Relup.Config.t()
) :: term()

Returns the name of the application.

This name is taken as argument for the run/1 function and is required to access the acceptor processes through the supervision tree

@spec call_this(arguments :: [term()]) ::
  Instruction.instruction() | Instruction.instructions()

Calls the run/1 function of this module

from the relup file during hot code upgrade

@spec dependencies() :: [instruction_module :: atom()]

Callback implementation for Edeliver.Relup.RunnableInstruction.dependencies/0.

@spec endpoint(otp_application_name :: atom()) :: pid()

Returns the pid of the phoenix endpoint supervisor

or throws and logs an error if it cannot be found. It supervises the Phoenix.Endpoint.Server which supervises the connections and acceptors, Phoenix.Config and the phoenix pubsub supervisor, e.g. Phoenix.PubSub.PG2.

@spec insert_where() :: Instruction.insert_fun()

Inserts the instruction before the point of no return.

This causes the release handler to abort the upgrade already when running :release_handler.check_install_release/1 if this instruction fails.

Callback implementation for Edeliver.Relup.Instruction.modify_relup/2.

@spec ranch_acceptors(ranch_acceptors_sup :: pid()) :: [:supervisor.child_id()]

Gets the supervisor child ids of the ranch socket accecptors

(ranch_acceptor) from the ranch acceptor supervisor or throws and logs an error if the acceptors cannot be found.

@spec ranch_acceptors_sup(ranch_listener_sup :: pid()) :: pid()

Gets the pid of the supervisor which supervises the ranch socket acceptors.

If it cannot be found as child of the given ranch listener supervisor it throws and logs an error.

@spec ranch_listener_sup(otp_application_name :: atom()) :: pid()

Gets the pid of the ranch listener supervisor

(:ranch_listener_sup) which supervises the ranch acceptors supervisor (:ranch_acceptors_sup) and the connections supervisor (:ranch_conns_sup). It throws and logs an error if they cannot be found in the supervison tree of the application.

@spec run(otp_application_name :: atom()) :: :ok

Checks whether the ranch acceptors can be found.

If not the upgrade will be canceled. This function runs twice because it is executed before the "point of no return", once when checking the relup and once when executing the relup.