[#3213] Prototype of data migrations functionality / HashtagsTableMigrator.

priv/repo/migrations/20210105195018_create_data_migrations.exs

@@ -0,0 +1,17 @@
+defmodule Pleroma.Repo.Migrations.CreateDataMigrations do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists table(:data_migrations) do
+      add(:name, :string, null: false)
+      add(:state, :integer, default: 1)
+      add(:feature_lock, :boolean, default: false)
+      add(:params, :map, default: %{})
+      add(:data, :map, default: %{})
+
+      timestamps()
+    end
+
+    create_if_not_exists(unique_index(:data_migrations, [:name]))
+  end
+end

priv/repo/migrations/20210106183301_data_migration_create_populate_hashtags_table.exs

@@ -0,0 +1,14 @@
+defmodule Pleroma.Repo.Migrations.DataMigrationCreatePopulateHashtagsTable do
+  use Ecto.Migration
+
+  def up do
+    dt = NaiveDateTime.utc_now()
+
+    execute(
+      "INSERT INTO data_migrations(name, inserted_at, updated_at) " <>
+        "VALUES ('populate_hashtags_table', '#{dt}', '#{dt}') ON CONFLICT DO NOTHING;"
+    )
+  end
+
+  def down, do: :ok
+end

priv/repo/migrations/20210111172254_create_data_migration_failed_ids.exs

@@ -0,0 +1,14 @@
+defmodule Pleroma.Repo.Migrations.CreateDataMigrationFailedIds do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists table(:data_migration_failed_ids, primary_key: false) do
+      add(:data_migration_id, references(:data_migrations), null: false)
+      add(:record_id, :bigint, null: false)
+    end
+
+    create_if_not_exists(
+      unique_index(:data_migration_failed_ids, [:data_migration_id, :record_id])
+    )
+  end
+end