Merge branch 'chores/bump-copyright' into 'develop'

[akkoma] / lib / pleroma / gun / connection_pool / worker.ex

diff --git a/lib/pleroma/gun/connection_pool/worker.ex b/lib/pleroma/gun/connection_pool/worker.ex
index 25fafc64c3c4de58f9db4f28f2874292f1ab27fb..02bfff2747ac3cfeaa1403aeb245a990b7c41bfa 100644 (file)
--- a/lib/pleroma/gun/connection_pool/worker.ex
+++ b/lib/pleroma/gun/connection_pool/worker.ex
@@ -1,42 +1,79 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2021 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
 defmodule Pleroma.Gun.ConnectionPool.Worker do
   alias Pleroma.Gun
   use GenServer, restart: :temporary
 
   @registry Pleroma.Gun.ConnectionPool
 
-  def start_link(opts) do
-    GenServer.start_link(__MODULE__, opts)
+  def start_link([key | _] = opts) do
+    GenServer.start_link(__MODULE__, opts, name: {:via, Registry, {@registry, key}})
+  end
+
+  @impl true
+  def init([_key, _uri, _opts, _client_pid] = opts) do
+    {:ok, nil, {:continue, {:connect, opts}}}
   end
 
   @impl true
-  def init([uri, key, opts, client_pid]) do
-    time = :os.system_time(:second)
-    # Register before opening connection to prevent race conditions
-    with {:ok, _owner} <- Registry.register(@registry, key, {nil, [client_pid], 1, time}),
-         {:ok, conn_pid} <- Gun.Conn.open(uri, opts),
+  def handle_continue({:connect, [key, uri, opts, client_pid]}, _) do
+    with {:ok, conn_pid, protocol} <- Gun.Conn.open(uri, opts),
          Process.link(conn_pid) do
+      time = :erlang.monotonic_time(:millisecond)
+
       {_, _} =
-        Registry.update_value(@registry, key, fn {_, used_by, crf, last_reference} ->
-          {conn_pid, used_by, crf, last_reference}
+        Registry.update_value(@registry, key, fn _ ->
+          {conn_pid, [client_pid], 1, time}
         end)
 
       send(client_pid, {:conn_pid, conn_pid})
-      {:ok, %{key: key, timer: nil}, :hibernate}
+
+      {:noreply,
+       %{
+         key: key,
+         timer: nil,
+         client_monitors: %{client_pid => Process.monitor(client_pid)},
+         protocol: protocol
+       }, :hibernate}
     else
-      err -> {:stop, err}
+      err ->
+        {:stop, {:shutdown, err}, nil}
+    end
+  end
+
+  @impl true
+  def handle_cast({:add_client, client_pid}, state) do
+    case handle_call(:add_client, {client_pid, nil}, state) do
+      {:reply, conn_pid, state, :hibernate} ->
+        send(client_pid, {:conn_pid, conn_pid})
+        {:noreply, state, :hibernate}
+    end
+  end
+
+  @impl true
+  def handle_cast({:remove_client, client_pid}, state) do
+    case handle_call(:remove_client, {client_pid, nil}, state) do
+      {:reply, _, state, :hibernate} ->
+        {:noreply, state, :hibernate}
     end
   end
 
   @impl true
-  def handle_cast({:add_client, client_pid, send_pid_back}, %{key: key} = state) do
-    time = :os.system_time(:second)
+  def handle_call(:add_client, {client_pid, _}, %{key: key, protocol: protocol} = state) do
+    time = :erlang.monotonic_time(:millisecond)
 
-    {{conn_pid, _, _, _}, _} =
+    {{conn_pid, used_by, _, _}, _} =
       Registry.update_value(@registry, key, fn {conn_pid, used_by, crf, last_reference} ->
         {conn_pid, [client_pid | used_by], crf(time - last_reference, crf), time}
       end)
 
-    if send_pid_back, do: send(client_pid, {:conn_pid, conn_pid})
+    :telemetry.execute(
+      [:pleroma, :connection_pool, :client, :add],
+      %{client_pid: client_pid, clients: used_by},
+      %{key: state.key, protocol: protocol}
+    )
 
     state =
       if state.timer != nil do
@@ -46,16 +83,23 @@ defmodule Pleroma.Gun.ConnectionPool.Worker do
         state
       end
 
-    {:noreply, state, :hibernate}
+    ref = Process.monitor(client_pid)
+
+    state = put_in(state.client_monitors[client_pid], ref)
+    {:reply, conn_pid, state, :hibernate}
   end
 
   @impl true
-  def handle_cast({:remove_client, client_pid}, %{key: key} = state) do
+  def handle_call(:remove_client, {client_pid, _}, %{key: key} = state) do
     {{_conn_pid, used_by, _crf, _last_reference}, _} =
       Registry.update_value(@registry, key, fn {conn_pid, used_by, crf, last_reference} ->
         {conn_pid, List.delete(used_by, client_pid), crf, last_reference}
       end)
 
+    {ref, state} = pop_in(state.client_monitors[client_pid])
+
+    Process.demonitor(ref, [:flush])
+
     timer =
       if used_by == [] do
         max_idle = Pleroma.Config.get([:connections_pool, :max_idle_time], 30_000)
@@ -64,7 +108,7 @@ defmodule Pleroma.Gun.ConnectionPool.Worker do
         nil
       end
 
-    {:noreply, %{state | timer: timer}, :hibernate}
+    {:reply, :ok, %{state | timer: timer}, :hibernate}
   end
 
   @impl true
@@ -74,20 +118,36 @@ defmodule Pleroma.Gun.ConnectionPool.Worker do
     {:stop, :normal, state}
   end
 
+  @impl true
+  def handle_info({:gun_up, _pid, _protocol}, state) do
+    {:noreply, state, :hibernate}
+  end
+
   # Gracefully shutdown if the connection got closed without any streams left
   @impl true
   def handle_info({:gun_down, _pid, _protocol, _reason, []}, state) do
     {:stop, :normal, state}
   end
 
-  # Otherwise, shutdown with an error
+  # Otherwise, wait for retry
+  @impl true
+  def handle_info({:gun_down, _pid, _protocol, _reason, _killed_streams}, state) do
+    {:noreply, state, :hibernate}
+  end
+
   @impl true
-  def handle_info({:gun_down, _pid, _protocol, _reason, _killed_streams} = down_message, state) do
-    {:stop, {:error, down_message}, state}
+  def handle_info({:DOWN, _ref, :process, pid, reason}, state) do
+    :telemetry.execute(
+      [:pleroma, :connection_pool, :client, :dead],
+      %{client_pid: pid, reason: reason},
+      %{key: state.key}
+    )
+
+    handle_cast({:remove_client, pid}, state)
   end
 
   # LRFU policy: https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.55.1478
   defp crf(time_delta, prev_crf) do
-    1 + :math.pow(0.5, time_delta / 100) * prev_crf
+    1 + :math.pow(0.5, 0.0001 * time_delta) * prev_crf
   end
 end