akkoma/lib/pleroma/pool/connections.ex
2020-03-03 09:29:51 +00:00

322 lines
8.3 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Pool.Connections do
use GenServer
alias Pleroma.Config
require Logger
@type domain :: String.t()
@type conn :: Pleroma.Gun.Conn.t()
@type t :: %__MODULE__{
conns: %{domain() => conn()},
opts: keyword()
}
defstruct conns: %{}, opts: []
alias Pleroma.Gun.API
@spec start_link({atom(), keyword()}) :: {:ok, pid()}
def start_link({name, opts}) do
GenServer.start_link(__MODULE__, opts, name: name)
end
@impl true
def init(opts), do: {:ok, %__MODULE__{conns: %{}, opts: opts}}
@spec checkin(String.t() | URI.t(), atom()) :: pid() | nil
def checkin(url, name)
def checkin(url, name) when is_binary(url), do: checkin(URI.parse(url), name)
def checkin(%URI{} = uri, name) do
timeout = Config.get([:connections_pool, :receive_connection_timeout], 250)
GenServer.call(
name,
{:checkin, uri},
timeout
)
end
@spec alive?(atom()) :: boolean()
def alive?(name) do
pid = Process.whereis(name)
if pid, do: Process.alive?(pid), else: false
end
@spec get_state(atom()) :: t()
def get_state(name) do
GenServer.call(name, :state)
end
@spec count(atom()) :: pos_integer()
def count(name) do
GenServer.call(name, :count)
end
@spec get_unused_conns(atom()) :: [{domain(), conn()}]
def get_unused_conns(name) do
GenServer.call(name, :unused_conns)
end
@spec checkout(pid(), pid(), atom()) :: :ok
def checkout(conn, pid, name) do
GenServer.cast(name, {:checkout, conn, pid})
end
@spec add_conn(atom(), String.t(), Pleroma.Gun.Conn.t()) :: :ok
def add_conn(name, key, conn) do
GenServer.cast(name, {:add_conn, key, conn})
end
@spec remove_conn(atom(), String.t()) :: :ok
def remove_conn(name, key) do
GenServer.cast(name, {:remove_conn, key})
end
@impl true
def handle_cast({:add_conn, key, conn}, state) do
state = put_in(state.conns[key], conn)
Process.monitor(conn.conn)
{:noreply, state}
end
@impl true
def handle_cast({:checkout, conn_pid, pid}, state) do
Logger.debug("checkout #{inspect(conn_pid)}")
state =
with true <- Process.alive?(conn_pid),
{key, conn} <- find_conn(state.conns, conn_pid),
used_by <- List.keydelete(conn.used_by, pid, 0) do
conn_state =
if used_by == [] do
:idle
else
conn.conn_state
end
put_in(state.conns[key], %{conn | conn_state: conn_state, used_by: used_by})
else
false ->
Logger.debug("checkout for closed conn #{inspect(conn_pid)}")
state
nil ->
Logger.debug("checkout for alive conn #{inspect(conn_pid)}, but is not in state")
state
end
{:noreply, state}
end
@impl true
def handle_cast({:remove_conn, key}, state) do
state = put_in(state.conns, Map.delete(state.conns, key))
{:noreply, state}
end
@impl true
def handle_call({:checkin, uri}, from, state) do
key = "#{uri.scheme}:#{uri.host}:#{uri.port}"
Logger.debug("checkin #{key}")
case state.conns[key] do
%{conn: conn, gun_state: :up} = current_conn ->
Logger.debug("reusing conn #{key}")
with time <- :os.system_time(:second),
last_reference <- time - current_conn.last_reference,
current_crf <- crf(last_reference, 100, current_conn.crf),
state <-
put_in(state.conns[key], %{
current_conn
| last_reference: time,
crf: current_crf,
conn_state: :active,
used_by: [from | current_conn.used_by]
}) do
{:reply, conn, state}
end
%{gun_state: gun_state} when gun_state == :down ->
{:reply, nil, state}
nil ->
{:reply, nil, state}
end
end
@impl true
def handle_call(:state, _from, state), do: {:reply, state, state}
@impl true
def handle_call(:count, _from, state) do
{:reply, Enum.count(state.conns), state}
end
@impl true
def handle_call(:unused_conns, _from, state) do
unused_conns =
state.conns
|> Enum.filter(fn {_k, v} ->
v.conn_state == :idle and v.used_by == []
end)
|> Enum.sort(fn {_x_k, x}, {_y_k, y} ->
x.crf <= y.crf and x.last_reference <= y.last_reference
end)
{:reply, unused_conns, state}
end
@impl true
def handle_info({:gun_up, conn_pid, _protocol}, state) do
state =
with conn_key when is_binary(conn_key) <- compose_key_gun_info(conn_pid),
{key, conn} <- find_conn(state.conns, conn_pid, conn_key),
{true, key} <- {Process.alive?(conn_pid), key},
time <- :os.system_time(:second),
last_reference <- time - conn.last_reference,
current_crf <- crf(last_reference, 100, conn.crf) do
put_in(state.conns[key], %{
conn
| gun_state: :up,
last_reference: time,
crf: current_crf,
conn_state: :active,
retries: 0
})
else
:error_gun_info ->
Logger.debug(":gun.info caused error")
state
{false, key} ->
Logger.debug(":gun_up message for closed conn #{inspect(conn_pid)}")
put_in(
state.conns,
Map.delete(state.conns, key)
)
nil ->
Logger.debug(":gun_up message for conn which is not found in state")
:ok = API.close(conn_pid)
state
end
{:noreply, state}
end
@impl true
def handle_info({:gun_down, conn_pid, _protocol, _reason, _killed}, state) do
retries = Config.get([:connections_pool, :retry], 0)
# we can't get info on this pid, because pid is dead
state =
with {key, conn} <- find_conn(state.conns, conn_pid),
{true, key} <- {Process.alive?(conn_pid), key} do
if conn.retries == retries do
Logger.debug("closing conn if retries is eq #{inspect(conn_pid)}")
:ok = API.close(conn.conn)
put_in(
state.conns,
Map.delete(state.conns, key)
)
else
put_in(state.conns[key], %{
conn
| gun_state: :down,
retries: conn.retries + 1
})
end
else
{false, key} ->
# gun can send gun_down for closed conn, maybe connection is not closed yet
Logger.debug(":gun_down message for closed conn #{inspect(conn_pid)}")
put_in(
state.conns,
Map.delete(state.conns, key)
)
nil ->
Logger.debug(":gun_down message for conn which is not found in state")
:ok = API.close(conn_pid)
state
end
{:noreply, state}
end
@impl true
def handle_info({:DOWN, _ref, :process, conn_pid, reason}, state) do
Logger.debug("received DOWM message for #{inspect(conn_pid)} reason -> #{inspect(reason)}")
state =
with {key, conn} <- find_conn(state.conns, conn_pid) do
Enum.each(conn.used_by, fn {pid, _ref} ->
Process.exit(pid, reason)
end)
put_in(
state.conns,
Map.delete(state.conns, key)
)
else
nil ->
Logger.debug(":DOWN message for conn which is not found in state")
state
end
{:noreply, state}
end
defp compose_key_gun_info(pid) do
try do
# sometimes :gun.info can raise MatchError, which lead to pool terminate
%{origin_host: origin_host, origin_scheme: scheme, origin_port: port} = API.info(pid)
host =
case :inet.ntoa(origin_host) do
{:error, :einval} -> origin_host
ip -> ip
end
"#{scheme}:#{host}:#{port}"
rescue
_ -> :error_gun_info
end
end
defp find_conn(conns, conn_pid) do
Enum.find(conns, fn {_key, conn} ->
conn.conn == conn_pid
end)
end
defp find_conn(conns, conn_pid, conn_key) do
Enum.find(conns, fn {key, conn} ->
key == conn_key and conn.conn == conn_pid
end)
end
def crf(current, steps, crf) do
1 + :math.pow(0.5, current / steps) * crf
end
def compose_uri_log(%URI{scheme: scheme, host: host, path: path}) do
"#{scheme}://#{host}#{path}"
end
end