elixir--phoenixlisted

# Elixir + Phoenix ## When to activate - Building Phoenix web applications or APIs - Designing OTP supervision trees with GenServer and Supervisor - Implementing Phoenix LiveView for server-rendered reactive UIs - Writing Ecto changesets and database transactions - Configuring mix releases for production deployment - Using the pipe operator and pattern matching idioms ## When NOT to use - Non-Elixir Erlang/OTP work where Elixir syntax is irrelevant - Simple scripting tasks better handled by a shell script - When the codebase is Elixir but the question is purely about PostgreSQL query optimization with no Ecto involvement ## Instructions ### GenServer Skeleton A GenServer is a stateful process. Implement all standard callbacks explicitly: ```elixir defmodule MyApp.Cache do use GenServer require Logger # --- Client API --- def start_link(opts \\ []) do GenServer.start_link(__MODULE__, opts, name: __MODULE__) end def get(key), do: GenServer.call(__MODULE__, {:get, key}) def put(key, value), do: GenServer.cast(__MODULE__, {:put, key, value}) def delete(key), do: GenServer.cast(__MODULE__, {:delete, key}) # --- Server Callbacks --- @impl true def init(_opts) do {:ok, %{}} # initial state is an empty map end @impl true def handle_call({:get, key}, _from, state) do {:reply, Map.get(state, key), state} end @impl true def handle_cast({:put, key, value}, state) do {:noreply, Map.put(state, key, value)} end @impl true