Lofi Eldritch beings to study with

Simulation of a cosmos of eldritch beings trying to learn cooperation and social organization.

• The Cosmos application is a work-in-progress implementation of an entity component system (ECS) which will power the simulation.

• The Eldritch library application is used to construct and interact with specific kinds of entities such as Being or Node entity.

• The Lofi application is a simple cowboy and plug based server for interacting with the simulation.

TODO

• change the local persistance directory to use temporary one that will only exist during the life time of the Cosmos Application.

Release Road map

Release Gamigin

• User can create beings with a information incantation
• Entities push a message to user have the interval time has elapsed

Cosmos ECS and Eldritch library

Starting the Cosmos ECS application

The Cosmos application can be started using

iex -S mix

This will start the various processes required to build entities, start systems, and begin a simulation.

Basic interaction with the lofi-eldritch-cosmos

To create a new being (a standard one with only default values for it's components)

curl -X POST http://localhost:5454/being

This will return something like

{"being_id": "2enp3IaLemeeiMDZYj3oJ0ukJ9U"}

which is the entity id for the being created. Now we can query for all existing beings with

curl -X GET http://localhost:5454/beings

and can get the full state of the being with

curl -X GET http://localhost:5454/being?id=2enp3IaLemeeiMDZYj3oJ0ukJ9U

Creating new entities

Entities can be created using the a builder module. For example, the Eldritch.Being.Builder module can be used to create a new being entity, with some of the standard attributes, use the build function with argument {:new, :being, :standard}. For example, after the Cosmos supervisor has been started one can run

being_entity_id = Eldritch.Being.Builder.build({:new, :being, :standard}, %{"name" => "Gor'lop"})

to create and spawn an entity worker for a being entity named "Gor'lop". The being's entity_id is returned so that we can fetch it's worker process using Cosmos.Entity.Cache.server_process(being_entity_id). The build function called in this way adds the standard components for a being.

The second argument can overwrite the default values used to create the standard components of an entity.

Systems acting on entities

Each entity is comprised of components each of which have a attribute system whose value is an atom corresponding to one of the implemented systems in the Cosmos ECS. When adding or removing a component, the entity is subscribed or unsubscribed respectively from the associated system. For example, in the previous section a being with standard components whose name is "Gor'lop" was created. This being has the form:

%Cosmos.Entity{
  id: "2NzPp7iRNFaaC10VMTpAgWvLxPK",
  components: %{
    1 => %Cosmos.Entity.Component{
      name: "name",
      system: :attribute,
      value: "Gor'lop",
      id: 1
    },
    2 => %Cosmos.Entity.Component{
      name: "ichor",
      system: :temporal_decay,
      value: 100,
      id: 2
    },
    3 => %Cosmos.Entity.Component{
      name: "orichalcum",
      system: :quantity,
      value: 100,
      id: 3
    }
  },
  auto_component_id: 4
}

Since this being has a component with the :temporal_decay system, it is subscribed to that system and the value ichor will decrease at a specified interval in time whenever the :temporal_decay system is turned on.

Starting and stopping systems

Systems are controlled by GenServers (see Cosmos.System.TemporalDecay for an example). The GenServer that powers each system is started when the Cosmos application starts up, but will not act on components of entities until being turned on. Systems can be started or stopped using Cosmos.System.on/1 and Cosmos.System.off/1 where the argument is the system atom (e.g. :temporal_decay).

Dependencies

• quantum is used for systems that need to be run at intervals of minutes or hours (such as full backups and health checks).
• cowboy

Scripts for specific situations

In the scripts directory are some elixir scripts that we can use to run specific small scale situations. These can be run by launching an iex session then compiling the script file. For example, first start the iex session with

iex -S mix

then one can run the script with

iex> c "scripts/{path-to-script}.exs"

Testing

Testing database workers

Launch the elixir REPL with

iex -S mix

Then run something like to make sure that database workers are behaving as expected.

iex(1)> Cosmos.Entity.Cache.start_link()
{:ok, #PID<0.215.0>}
iex(2)> server = Cosmos.Entity.Server.start_link("jorsa")
{:ok, #PID<0.221.0>}
iex(3)> {_, server} = server
{:ok, #PID<0.221.0>}
iex(4)> entity = Cosmos.Entity.Server.get(server)
%Cosmos.Entity{
  id: "2MXHjNmnZAfLUZToIExXE5xrXiL",
  components: %{},
  auto_component_id: 1
}
iex(5)> comp = Cosmos.Entity.Component.new("name", :attribute, "johnson")
%Cosmos.Entity.Component{name: "name", system: :attribute, value: "johnson", id: nil}
iex(6)> Cosmos.Entity.Server.add_component(server, comp)
:ok
#PID<0.217.0> was chosen

Appendix

Naming convention for releases

Release names can be chosen from marquises from Ars Geotia