neiam /gitgud

defmodule GitGud.Repo.Migrations.AddRunnerAgentLabels do
  use Ecto.Migration

  @moduledoc """
  Split `runners.labels` into two columns:

    * `labels`        — operator-assigned. Source of truth for which
                        jobs the runner picks up. Set via the
                        offline-mint UI / mix task; never touched by
                        the runner's `Declare` RPC.
    * `agent_labels`  — runner-self-reported. The runner tells us what
                        it can do on every `Declare`; we record but
                        don't use for routing. Surfaced in the UI for
                        operator visibility.

  Before this split, `Declare` overwrote `labels` with whatever the
  runner sent, which silently invalidated operator intent on the next
  runner restart.

  Backfill: copy existing `labels` to `agent_labels` so prior runners
  keep their (admittedly self-reported) labels until an operator
  re-mints. Same JSONB shape: `%{"labels" => [...]}`.
  """

  def up do
    alter table(:runners) do
      add :agent_labels, :map, default: %{"labels" => []}
    end

    execute "UPDATE runners SET agent_labels = labels"
  end

  def down do
    alter table(:runners) do
      remove :agent_labels
    end
  end
end