akkoma/lib/pleroma/pool/connections.ex

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# 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
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
alias Pleroma.Gun.Conn
@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 = Pleroma.Config.get([:connections_pool, :receive_connection_timeout], 250)
GenServer.call(
name,
{:checkin, uri},
timeout
)
end
@spec open_conn(String.t() | URI.t(), atom(), keyword()) :: :ok
def open_conn(url, name, opts \\ [])
def open_conn(url, name, opts) when is_binary(url), do: open_conn(URI.parse(url), name, opts)
def open_conn(%URI{} = uri, name, opts) do
pool_opts = Pleroma.Config.get([:connections_pool], [])
opts =
opts
|> Enum.into(%{})
|> Map.put_new(:retry, pool_opts[:retry] || 0)
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|> Map.put_new(:retry_timeout, pool_opts[:retry_timeout] || 100)
|> Map.put_new(:await_up_timeout, pool_opts[:await_up_timeout] || 5_000)
GenServer.cast(name, {:open_conn, %{opts: opts, uri: uri}})
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 checkout(pid(), pid(), atom()) :: :ok
def checkout(conn, pid, name) do
GenServer.cast(name, {:checkout, conn, pid})
end
@impl true
def handle_cast({:open_conn, %{opts: opts, uri: uri}}, state) do
Logger.debug("opening new #{compose_uri(uri)}")
max_connections = state.opts[:max_connections]
key = compose_key(uri)
if Enum.count(state.conns) < max_connections do
open_conn(key, uri, state, opts)
else
try_to_open_conn(key, uri, state, opts)
end
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)}")
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state
nil ->
Logger.debug("checkout for alive conn #{inspect(conn_pid)}, but is not in state")
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state
end
{:noreply, state}
end
@impl true
def handle_call({:checkin, uri}, from, state) do
Logger.debug("checkin #{compose_uri(uri)}")
key = compose_key(uri)
case state.conns[key] do
%{conn: conn, gun_state: gun_state} = current_conn when gun_state == :up ->
Logger.debug("reusing conn #{compose_uri(uri)}")
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_info({:gun_up, conn_pid, _protocol}, state) do
state =
with true <- Process.alive?(conn_pid),
conn_key when is_binary(conn_key) <- compose_key_gun_info(conn_pid),
{key, conn} <- find_conn(state.conns, conn_pid, conn_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")
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state
false ->
Logger.debug(":gun_up message for closed conn #{inspect(conn_pid)}")
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state
nil ->
Logger.debug(
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":gun_up message for alive conn #{inspect(conn_pid)}, but deleted from 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
# we can't get info on this pid, because pid is dead
state =
with true <- Process.alive?(conn_pid),
{key, conn} <- find_conn(state.conns, conn_pid) do
if conn.retries == 5 do
Logger.debug("closing conn if retries is eq 5 #{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 ->
# 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)}")
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state
nil ->
Logger.debug(
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":gun_down message for alive conn #{inspect(conn_pid)}, but deleted from state"
)
:ok = API.close(conn_pid)
state
end
{:noreply, state}
end
defp compose_key(%URI{scheme: scheme, host: host, port: port}), do: "#{scheme}:#{host}:#{port}"
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
defp open_conn(key, uri, state, %{proxy: {proxy_host, proxy_port}} = opts) do
connect_opts =
uri
|> destination_opts()
|> add_http2_opts(uri.scheme, Map.get(opts, :tls_opts, []))
with open_opts <- Map.delete(opts, :tls_opts),
{:ok, conn} <- API.open(proxy_host, proxy_port, open_opts),
{:ok, _} <- API.await_up(conn),
stream <- API.connect(conn, connect_opts),
{:response, :fin, 200, _} <- API.await(conn, stream),
state <-
put_in(state.conns[key], %Conn{
conn: conn,
gun_state: :up,
conn_state: :active,
last_reference: :os.system_time(:second)
}) do
{:noreply, state}
else
error ->
Logger.warn(
"Received error on opening connection with http proxy #{uri.scheme}://#{
compose_uri(uri)
}: #{inspect(error)}"
)
{:noreply, state}
end
end
defp open_conn(key, uri, state, %{proxy: {proxy_type, proxy_host, proxy_port}} = opts) do
version =
proxy_type
|> to_string()
|> String.last()
|> case do
"4" -> 4
_ -> 5
end
socks_opts =
uri
|> destination_opts()
|> add_http2_opts(uri.scheme, Map.get(opts, :tls_opts, []))
|> Map.put(:version, version)
opts =
opts
|> Map.put(:protocols, [:socks])
|> Map.put(:socks_opts, socks_opts)
with {:ok, conn} <- API.open(proxy_host, proxy_port, opts),
{:ok, _} <- API.await_up(conn),
state <-
put_in(state.conns[key], %Conn{
conn: conn,
gun_state: :up,
conn_state: :active,
last_reference: :os.system_time(:second)
}) do
{:noreply, state}
else
error ->
Logger.warn(
"Received error on opening connection with socks proxy #{uri.scheme}://#{
compose_uri(uri)
}: #{inspect(error)}"
)
{:noreply, state}
end
end
defp open_conn(key, %URI{host: host, port: port} = uri, state, opts) do
Logger.debug("opening conn #{compose_uri(uri)}")
{_type, host} = Pleroma.HTTP.Adapter.domain_or_ip(host)
with {:ok, conn} <- API.open(host, port, opts),
{:ok, _} <- API.await_up(conn),
state <-
put_in(state.conns[key], %Conn{
conn: conn,
gun_state: :up,
conn_state: :active,
last_reference: :os.system_time(:second)
}) do
Logger.debug("new conn opened #{compose_uri(uri)}")
Logger.debug("replying to the call #{compose_uri(uri)}")
{:noreply, state}
else
error ->
Logger.warn(
"Received error on opening connection #{uri.scheme}://#{compose_uri(uri)}: #{
inspect(error)
}"
)
{:noreply, state}
end
end
defp destination_opts(%URI{host: host, port: port}) do
{_type, host} = Pleroma.HTTP.Adapter.domain_or_ip(host)
%{host: host, port: port}
end
defp add_http2_opts(opts, "https", tls_opts) do
Map.merge(opts, %{protocols: [:http2], transport: :tls, tls_opts: tls_opts})
end
defp add_http2_opts(opts, _, _), do: opts
@spec get_unused_conns(map()) :: [{domain(), conn()}]
def get_unused_conns(conns) do
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)
end
defp try_to_open_conn(key, uri, state, opts) do
Logger.debug("try to open conn #{compose_uri(uri)}")
with [{close_key, least_used} | _conns] <- get_unused_conns(state.conns),
:ok <- API.close(least_used.conn),
state <-
put_in(
state.conns,
Map.delete(state.conns, close_key)
) do
Logger.debug(
"least used conn found and closed #{inspect(least_used.conn)} #{compose_uri(uri)}"
)
open_conn(key, uri, state, opts)
else
[] -> {:noreply, state}
end
end
def crf(current, steps, crf) do
1 + :math.pow(0.5, current / steps) * crf
end
def compose_uri(%URI{} = uri), do: "#{uri.host}#{uri.path}"
end