honkoma/lib/pleroma/repo_streamer.ex

35 lines
746 B
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.RepoStreamer do
alias Pleroma.Repo
import Ecto.Query
def chunk_stream(query, chunk_size) do
Stream.unfold(0, fn
:halt ->
{[], :halt}
last_id ->
query
|> order_by(asc: :id)
|> where([r], r.id > ^last_id)
|> limit(^chunk_size)
|> Repo.all()
|> case do
[] ->
{[], :halt}
records ->
last_id = List.last(records).id
{records, last_id}
end
end)
|> Stream.take_while(fn
[] -> false
_ -> true
end)
end
end