akkoma/lib/pleroma/migrators/support/base_migrator.ex

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# Pleroma: A lightweight social networking server
# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Migrators.Support.BaseMigrator do
@moduledoc """
Base background migrator functionality.
"""
@callback perform() :: any()
@callback retry_failed() :: any()
@callback feature_config_path() :: list(atom())
@callback query() :: Ecto.Query.t()
@callback fault_rate_allowance() :: integer() | float()
defmacro __using__(_opts) do
quote do
use GenServer
require Logger
import Ecto.Query
alias __MODULE__.State
alias Pleroma.Config
alias Pleroma.Repo
@behaviour Pleroma.Migrators.Support.BaseMigrator
defdelegate data_migration(), to: State
defdelegate data_migration_id(), to: State
defdelegate state(), to: State
defdelegate persist_state(), to: State, as: :persist_to_db
defdelegate get_stat(key, value \\ nil), to: State, as: :get_data_key
defdelegate put_stat(key, value), to: State, as: :put_data_key
defdelegate increment_stat(key, increment), to: State, as: :increment_data_key
@reg_name {:global, __MODULE__}
def whereis, do: GenServer.whereis(@reg_name)
def start_link(_) do
case whereis() do
nil ->
GenServer.start_link(__MODULE__, nil, name: @reg_name)
pid ->
{:ok, pid}
end
end
@impl true
def init(_) do
{:ok, nil, {:continue, :init_state}}
end
@impl true
def handle_continue(:init_state, _state) do
{:ok, _} = State.start_link(nil)
data_migration = data_migration()
manual_migrations = Config.get([:instance, :manual_data_migrations], [])
cond do
Config.get(:env) == :test ->
update_status(:noop)
is_nil(data_migration) ->
message = "Data migration does not exist."
update_status(:failed, message)
Logger.error("#{__MODULE__}: #{message}")
data_migration.state == :manual or data_migration.name in manual_migrations ->
message = "Data migration is in manual execution or manual fix mode."
update_status(:manual, message)
Logger.warn("#{__MODULE__}: #{message}")
data_migration.state == :complete ->
on_complete(data_migration)
true ->
send(self(), :perform)
end
{:noreply, nil}
end
@impl true
def handle_info(:perform, state) do
State.reinit()
update_status(:running)
put_stat(:iteration_processed_count, 0)
put_stat(:started_at, NaiveDateTime.utc_now())
perform()
fault_rate = fault_rate()
put_stat(:fault_rate, fault_rate)
fault_rate_allowance = fault_rate_allowance()
cond do
fault_rate == 0 ->
set_complete()
is_float(fault_rate) and fault_rate <= fault_rate_allowance ->
message = """
Done with fault rate of #{fault_rate} which doesn't exceed #{fault_rate_allowance}.
Putting data migration to manual fix mode. Try running `#{__MODULE__}.retry_failed/0`.
"""
Logger.warn("#{__MODULE__}: #{message}")
update_status(:manual, message)
on_complete(data_migration())
true ->
message = "Too many failures. Try running `#{__MODULE__}.retry_failed/0`."
Logger.error("#{__MODULE__}: #{message}")
update_status(:failed, message)
end
persist_state()
{:noreply, state}
end
defp on_complete(data_migration) do
if data_migration.feature_lock || feature_state() == :disabled do
Logger.warn(
"#{__MODULE__}: migration complete but feature is locked; consider enabling."
)
:noop
else
Config.put(feature_config_path(), :enabled)
:ok
end
end
@doc "Approximate count for current iteration (including processed records count)"
def count(force \\ false, timeout \\ :infinity) do
stored_count = get_stat(:count)
if stored_count && !force do
stored_count
else
processed_count = get_stat(:processed_count, 0)
max_processed_id = get_stat(:max_processed_id, 0)
query = where(query(), [entity], entity.id > ^max_processed_id)
count = Repo.aggregate(query, :count, :id, timeout: timeout) + processed_count
put_stat(:count, count)
persist_state()
count
end
end
def failures_count do
with {:ok, %{rows: [[count]]}} <-
Repo.query(
"SELECT COUNT(record_id) FROM data_migration_failed_ids WHERE data_migration_id = $1;",
[data_migration_id()]
) do
count
end
end
def feature_state, do: Config.get(feature_config_path())
def force_continue do
send(whereis(), :perform)
end
def force_restart do
:ok = State.reset()
force_continue()
end
def set_complete do
update_status(:complete)
persist_state()
on_complete(data_migration())
end
defp update_status(status, message \\ nil) do
put_stat(:state, status)
put_stat(:message, message)
end
defp fault_rate do
with failures_count when is_integer(failures_count) <- failures_count() do
failures_count / Enum.max([get_stat(:affected_count, 0), 1])
else
_ -> :error
end
end
defp records_per_second do
get_stat(:iteration_processed_count, 0) / Enum.max([running_time(), 1])
end
defp running_time do
NaiveDateTime.diff(
NaiveDateTime.utc_now(),
get_stat(:started_at, NaiveDateTime.utc_now())
)
end
end
end
end