Multitask

v0.1.0

Multitask v0.1.0 Multitask.Supervisor View Source

A multitask supervisor.

This module defines a supervisor which can be used to dynamically supervise Multitask.

start_link/1 can be used to start the supervisor. See the Multitask module for more examples.

Name registration

A Multitask.Supervisor is bound to the same name registration rules as a GenServer. Read more about them in the GenServer docs.

Link to this section Summary

Types

option()

Option values used by start_link

Functions

async(supervisor, functions)

Starts a multitask that can be awaited on

async_nolink(supervisor, functions)

Starts a multitask that can be awaited on

children(supervisor)

Returns all children PIDs

start_child(supervisor, functions)

Starts a multitask as a child of the given supervisor

start_link(opts \\ [])

Starts a new supervisor

terminate_child(supervisor, pid)

Terminates the child with the given pid

Link to this section Types

Link to this type option() View Source 
option ::
  Supervisor.option |
  {:restart, :supervisor.restart} |
  {:shutdown, :supervisor.shutdown}

Option values used by start_link

Link to this section Functions

Link to this function async(supervisor, functions) View Source 
async(Supervisor.supervisor, [function | mfa]) :: Multitask.t

Starts a multitask that can be awaited on.

The supervisor must be a reference as defined in Multitask.Supervisor. The multitask will still be linked to the caller, see Multitask.async/3 for more information and async_nolink/2 for a non-linked variant.

Note this function requires the multitask supervisor to have :temporary as the :restart option (the default), as async/2 keeps a direct reference to the multitask which is lost if the multitask is restarted.

Link to this function async_nolink(supervisor, functions) View Source 
async_nolink(Supervisor.supervisor, [function | mfa]) :: Multitask.t

Starts a multitask that can be awaited on.

The supervisor must be a reference as defined in Multitask.Supervisor. The multitask won’t be linked to the caller, see Multitask.async/3 for more information.

Note this function requires the multitask supervisor to have :temporary as the :restart option (the default), as async_nolink/2 keeps a direct reference to the multitask which is lost if the multitask is restarted.

Compatibility with OTP behaviours

If you create a task using async_nolink inside an OTP behaviour like GenServer, you should match on the message coming from the multitask inside your GenServer.handle_info/2 callback.

The reply sent by the multitask will be in the format {ref, result}, where ref is the monitor reference held by the multitask struct and result is the return value of the multitask functions.

Keep in mind that, regardless of how the multitask created with async_nolink terminates, the caller’s process will always receive a :DOWN message with the same ref value that is held by the multitask struct. If the multitask terminates normally, the reason in the :DOWN message will be :normal.

Link to this function children(supervisor) View Source 
children(Supervisor.supervisor) :: [pid]

Returns all children PIDs.

Link to this function start_child(supervisor, functions) View Source 
start_child(Supervisor.supervisor, [function | mfa]) :: {:ok, pid}

Starts a multitask as a child of the given supervisor.

Note that the spawned process is not linked to the caller, but only to the supervisor. This command is useful in case the multitask needs to perform side-effects (like I/O) and does not need to report back to the caller.

Link to this function start_link(opts \\ []) View Source 
start_link([option]) :: Supervisor.on_start

Starts a new supervisor.

The supported options are:

  • :name - used to register a supervisor name, the supported values are described under the Name Registration section in the GenServer module docs;

  • :restart - the restart strategy, may be :temporary (the default), :transient or :permanent. :temporary means the task is never restarted, :transient means it is restarted if the exit is not :normal, :shutdown or {:shutdown, reason}. A :permanent restart strategy means it is always restarted. It defaults to :temporary so multitasks aren’t automatically restarted when they complete nor in case of crashes. Note the :async functions in this module support only :temporary restarts;

  • :shutdown - :brutal_kill if the multitasks must be killed directly on shutdown or an integer indicating the timeout value, defaults to 5000 milliseconds;

  • :max_restarts and :max_seconds - as specified in Supervisor;

Link to this function terminate_child(supervisor, pid) View Source 
terminate_child(Supervisor.supervisor, pid) :: :ok

Terminates the child with the given pid.