module arch.node.engines.router;

import arch.node.engines.router_messages open;
import arch.node.engines.router_config open;
import arch.node.engines.router_environment open;
import arch.node.engines.router_behaviour open;
import arch.node.types.basics open;
import arch.node.types.engine open;
import arch.node.types.anoma as Anoma open;

open router_config_example;
open router_environment_example;
open router_behaviour_example;

Router Engine¶

Purpose¶

The Router engine is responsible for routing messages between local engines and remote nodes.

Operation¶

The Router may operate in different modes depending on requirements and constraints of the implementation:

Centralized

A single Router engine instance forwards messages to & from local engines. It may integrate the functionality of Pub/Sub Topic engines as well.

Decentralized

A separate Router engine instance is spawned for each destination node, each of which forward messages for a single node only. The engine instance name is derived from NodeID of the destination, which allows local engines to forward outgoing messages via the router engine instance responsible for the destination.

Spawning of Router and Pub/Sub Topic engines may be implemented either manually when the first message is sent to the node or when the topic is subscribed, or automatically as soon as a NodeAdvert or TopicAdvert is known for the destination.

In the following we assume decentralized operation with automatic spawning for simplicity.

Engine components¶

• Router Messages
• Router Configuration
• Router Environment
• Router Behaviour

The type for a router engine¶

RouterEngine : Type :=
  Engine
    RouterLocalCfg
    RouterLocalState
    RouterMailboxState
    RouterTimerHandle
    RouterActionArguments
    Anoma.Msg
    Anoma.Cfg
    Anoma.Env;

Example of a router engine¶

exRouterEngine : RouterEngine :=
  mkEngine@{
    cfg := exRouterCfg;
    env := exRouterEnv;
    behaviour := exRouterBehaviour;
  };

Where exRouterCfg is defined as follows:

exRouterCfg : RouterCfg :=
  mkEngineCfg@{
    node := Curve25519PubKey "0xabcd1234";
    name := "router-0xab12cd34";
    cfg := mkRouterLocalCfg;
  };

exRouterEnv is defined as follows:

exRouterEnv : RouterEnv :=
  mkEngineEnv@{
    localState := mkRouterLocalState;
    mailboxCluster := Map.empty;
    acquaintances := Set.empty;
    timers := [];
  };

and exRouterBehaviour is defined as follows:

module router_behaviour_example;
  exRouterBehaviour : RouterBehaviour :=
    mkEngineBehaviour@{
      guards := First [exampleReplyGuard];
    };
end;