Tracks Legion agents from a PostgreSQL-backed Legion.Store.

This tracker rebuilds the dashboard from persisted conversations, so agents remain visible after their processes or the application stop. It also listens for PostgreSQL notifications and publishes live dashboard updates without polling.

Usage

Define a Legion.Store.Postgres store and configure it for Legion:

defmodule MyApp.AgentStore do
  use Legion.Store.Postgres, repo: MyApp.Repo
end

config :legion, :store, MyApp.AgentStore

Configure LegionWeb to use it:

config :legion_web, :agent_tracker,
  {LegionWeb.AgentTracker.Postgres, store: MyApp.AgentStore}

Requirements

The configured store must implement Legion.Store and expose the __repo__/0 and __table__/0 functions generated by Legion.Store.Postgres. The host application must provide an Ecto repo backed by Ecto.Adapters.Postgres and include Postgrex.

Tracking behavior

The tracker loads up to 100 persisted conversations. It resolves each agent_id through Legion.lookup/1 to distinguish live agents from stopped ones, and reconstructs durable user, assistant, eval-result, and error events from the stored conversation.

PostgreSQL notifications reload the affected conversation and broadcast its current status and usage. Historical events are loaded when an agent is opened; later notifications broadcast only newly appended events.

Usage comes from the store's usage column, which Legion appends to at the end of each turn, so usage updates arrive per turn rather than per request.