Supervision and OTP

GenServer Architecture

FlagsGG.Client is a GenServer that owns:

• An ETS table for the flag cache
• A circuit breaker for API failure tracking
• A background refresh loop driven by the API’s intervalAllowed value

By starting it under your application’s supervisor, OTP restarts the client automatically if it crashes — your flag cache rebuilds on the next refresh.

Adding to Your Supervision Tree

lib/my_app/application.ex

defmodule MyApp.Application do
  use Application

  def start(_type, _args) do
    children = [
      MyApp.Repo,
      {FlagsGG,
        project_id: "your-project-id",
        agent_id: "your-agent-id",
        environment_id: "your-environment-id"},
      MyAppWeb.Endpoint
    ]

    opts = [strategy: :one_for_one, name: MyApp.Supervisor]
    Supervisor.start_link(children, opts)
  end
end

Phoenix Integration

In a Phoenix controller or LiveView, just call FlagsGG.enabled?/1:

defmodule MyAppWeb.PageController do
  use MyAppWeb, :controller

  def index(conn, _params) do
    if FlagsGG.enabled?("new-homepage") do
      render(conn, :new_home)
    else
      render(conn, :home)
    end
  end
end

defmodule MyAppWeb.DashboardLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    {:ok, assign(socket, beta?: FlagsGG.enabled?("beta-dashboard"))}
  end
end

Concurrent Access

The cache is backed by ETS with :read_concurrency enabled, so flag lookups from many processes do not contend on the GenServer. Lookups are resolved directly against ETS — only refreshes go through the GenServer.

Releases

When building releases with mix release, no extra configuration is needed. The supervisor and child spec are picked up the same way as in development.