akkoma/lib/pleroma/reverse_proxy/client/tesla.ex
rinpatch 58a4f350a8 Refactor gun pooling and simplify adapter option insertion
This patch refactors gun pooling to use Elixir process registry and
simplifies adapter option insertion.

Having the pool use process registry instead of a GenServer has a number of advantages:
- Simpler code: the initial implementation adds about half the lines of code it deletes
- Concurrency: unlike a GenServer, ETS-based registry can handle multiple checkout/checkin
requests at the same time
- Precise and easy idle connection clousure: current proposal for closing idle connections in
the GenServer-based pool needs to filter through all connections once a minute and compare their
last active time with closing time. With Elixir process registry this can be done
by just using `Process.send_after`/`Process.cancel_timer` in the worker process.
- Lower memory footprint: In my tests `gun-memory-leak` branch uses about 290mb on peak load (250 connections)
and 235mb on idle (5-10 connections). Registry-based pool uses 210mb on idle and 240mb on peak load
2020-07-15 15:17:27 +03:00

91 lines
2.4 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.ReverseProxy.Client.Tesla do
@behaviour Pleroma.ReverseProxy.Client
@type headers() :: [{String.t(), String.t()}]
@type status() :: pos_integer()
@spec request(atom(), String.t(), headers(), String.t(), keyword()) ::
{:ok, status(), headers}
| {:ok, status(), headers, map()}
| {:error, atom() | String.t()}
| no_return()
@impl true
def request(method, url, headers, body, opts \\ []) do
check_adapter()
opts = Keyword.put(opts, :body_as, :chunks)
with {:ok, response} <-
Pleroma.HTTP.request(
method,
url,
body,
headers,
Keyword.put(opts, :adapter, opts)
) do
if is_map(response.body) and method != :head do
{:ok, response.status, response.headers, response.body}
else
{:ok, response.status, response.headers}
end
else
{:error, error} -> {:error, error}
end
end
@impl true
@spec stream_body(map()) ::
{:ok, binary(), map()} | {:error, atom() | String.t()} | :done | no_return()
def stream_body(%{pid: pid, opts: opts, fin: true}) do
# if connection was reused, but in tesla were redirects,
# tesla returns new opened connection, which must be closed manually
if opts[:old_conn], do: Tesla.Adapter.Gun.close(pid)
# if there were redirects we need to checkout old conn
conn = opts[:old_conn] || opts[:conn]
if conn, do: :ok = Pleroma.Gun.ConnectionPool.release_conn(conn)
:done
end
def stream_body(client) do
case read_chunk!(client) do
{:fin, body} ->
{:ok, body, Map.put(client, :fin, true)}
{:nofin, part} ->
{:ok, part, client}
{:error, error} ->
{:error, error}
end
end
defp read_chunk!(%{pid: pid, stream: stream, opts: opts}) do
adapter = check_adapter()
adapter.read_chunk(pid, stream, opts)
end
@impl true
@spec close(map) :: :ok | no_return()
def close(%{pid: pid}) do
adapter = check_adapter()
adapter.close(pid)
end
defp check_adapter do
adapter = Application.get_env(:tesla, :adapter)
unless adapter == Tesla.Adapter.Gun do
raise "#{adapter} doesn't support reading body in chunks"
end
adapter
end
end