lkn-core v0.4.3 Lkn.Core.Instance View Source

A Process to arbitrate the Systems of a given Map.

There are two things to remember about Instances:

  1. There can be several Instances of a single Map
  2. They are dynamically created by the Lkn.Core.Pool of a Map when required

In other words, it is not the developer job to spawn an Instance. You can see an instance as the entry point of a game scene. It acts as a proxy between Lkn.Core.Puppeteers and Lkn.Core.Systems.

An Instance will stay alive as long as it hosts at least one Lkn.Core.Puppeteer. Once it has became empty, it warns its Lkn.Core.Pool so that the Pool can kill it.

Link to this section Summary

Types

k()

A key to identify and reach an Instance

Functions

Returns a specification to start this module under a supervisor

Invoked when the server is started. start_link/3 or start/3 will block until it returns

Insert a new Puppet into an Instance

Remove a Puppet from an Instance

Notify an Instance that a given Puppeteer is leaving

Link to this section Types

A key to identify and reach an Instance.

Link to this section Functions

Returns a specification to start this module under a supervisor.

See Supervisor.

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

args is the argument term (second argument) passed to start_link/3.

Returning {:ok, state} will cause start_link/3 to return {:ok, pid} and the process to enter its loop.

Returning {:ok, state, timeout} is similar to {:ok, state} except handle_info(:timeout, state) will be called after timeout milliseconds if no messages are received within the timeout.

Returning {:ok, state, :hibernate} is similar to {:ok, state} except the process is hibernated before entering the loop. See c:handle_call/3 for more information on hibernation.

Returning :ignore will cause start_link/3 to return :ignore and the process will exit normally without entering the loop or calling c:terminate/2. If used when part of a supervision tree the parent supervisor will not fail to start nor immediately try to restart the GenServer. The remainder of the supervision tree will be (re)started and so the GenServer should not be required by other processes. It can be started later with Supervisor.restart_child/2 as the child specification is saved in the parent supervisor. The main use cases for this are:

  • The GenServer is disabled by configuration but might be enabled later.
  • An error occurred and it will be handled by a different mechanism than the Supervisor. Likely this approach involves calling Supervisor.restart_child/2 after a delay to attempt a restart.

Returning {:stop, reason} will cause start_link/3 to return {:error, reason} and the process to exit with reason reason without entering the loop or calling c:terminate/2.

Callback implementation for GenServer.init/1.

Link to this function notify_puppeteers(instance_key, notif) View Source
Link to this function register_puppet(instance_key, puppet_key, opts \\ %{}) View Source
register_puppet(k(), Lkn.Core.Puppet.k(), %{optional(Lkn.Core.System.m()) => Keyworld.t()}) :: boolean()

Insert a new Puppet into an Instance.

This function can be used by a Lkn.Core.Puppeteer to insert a new Puppet into an Instance. There is no notion of Puppet owner, from an Instance point of view. Therefore, any Puppeteer can send a command “on behalf of a given Puppet. This Puppeteer will have the obligation to unregister it.

Under the hood, this function dispatches the register event to each system the Puppet has a Component for.

Link to this function unregister_puppet(instance_key, puppet_key) View Source
unregister_puppet(k(), Lkn.Core.Puppet.k()) :: boolean()

Remove a Puppet from an Instance.

This function can be used by a Lkn.Core.Puppeteer to an Instance. An Instance will never do it by itself, so it needs to be done by the Puppeteer owner, e.g. before it registers istelf. Note that, if the Puppeteer forgets to unregister one of its Puppets, this Puppets will stay in this Instance as long as at least one Puppeteer stays registered (and it will probably do nothing at all).

Link to this function unregister_puppeteer(instance_key, puppeteer_key) View Source
unregister_puppeteer(k(), Lkn.Core.Puppeteer.k()) :: :ok

Notify an Instance that a given Puppeteer is leaving.

This function needs to be used by a Puppeteer, after it has removed all of its Puppets. Right now, a Puppeteer cannot choose its Instance to join, and the Lkn.Core.Pool.register_puppeteer is the function to use to join the Instance of a given Map.