Merge branch 'features/add-credo-to-ci' into 'develop'
[akkoma] / lib / pleroma / web / federator / retry_queue.ex
index 06c094f265aa270ba2c62b0fa7a156e909a2d987..71e49494fd5a381616b6ed7a7eb324cba0112558 100644 (file)
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
 defmodule Pleroma.Web.Federator.RetryQueue do
   use GenServer
-  alias Pleroma.Web.{WebFinger, Websub}
-  alias Pleroma.Web.ActivityPub.ActivityPub
-  require Logger
 
-  @websub Application.get_env(:pleroma, :websub)
-  @ostatus Application.get_env(:pleroma, :websub)
-  @httpoison Application.get_env(:pleroma, :websub)
-  @instance Application.get_env(:pleroma, :websub)
-  # initial timeout, 5 min
-  @initial_timeout 30_000
-  @max_retries 5
+  require Logger
 
   def init(args) do
-    {:ok, args}
+    queue_table = :ets.new(:pleroma_retry_queue, [:bag, :protected])
+
+    {:ok, %{args | queue_table: queue_table, running_jobs: :sets.new()}}
   end
 
-  def start_link() do
-    GenServer.start_link(__MODULE__, %{delivered: 0, dropped: 0}, name: __MODULE__)
+  def start_link do
+    enabled =
+      if Mix.env() == :test, do: true, else: Pleroma.Config.get([__MODULE__, :enabled], false)
+
+    if enabled do
+      Logger.info("Starting retry queue")
+
+      linkres =
+        GenServer.start_link(
+          __MODULE__,
+          %{delivered: 0, dropped: 0, queue_table: nil, running_jobs: nil},
+          name: __MODULE__
+        )
+
+      maybe_kickoff_timer()
+      linkres
+    else
+      Logger.info("Retry queue disabled")
+      :ignore
+    end
   end
 
   def enqueue(data, transport, retries \\ 0) do
     GenServer.cast(__MODULE__, {:maybe_enqueue, data, transport, retries + 1})
   end
 
+  def get_stats do
+    GenServer.call(__MODULE__, :get_stats)
+  end
+
+  def reset_stats do
+    GenServer.call(__MODULE__, :reset_stats)
+  end
+
   def get_retry_params(retries) do
-    if retries > @max_retries do
+    if retries > Pleroma.Config.get([__MODULE__, :max_retries]) do
       {:drop, "Max retries reached"}
     else
       {:retry, growth_function(retries)}
     end
   end
 
-  def handle_cast({:maybe_enqueue, data, transport, retries}, %{dropped: drop_count} = state) do
+  def get_retry_timer_interval do
+    Pleroma.Config.get([:retry_queue, :interval], 1000)
+  end
+
+  defp ets_count_expires(table, current_time) do
+    :ets.select_count(
+      table,
+      [
+        {
+          {:"$1", :"$2"},
+          [{:"=<", :"$1", {:const, current_time}}],
+          [true]
+        }
+      ]
+    )
+  end
+
+  defp ets_pop_n_expired(table, current_time, desired) do
+    {popped, _continuation} =
+      :ets.select(
+        table,
+        [
+          {
+            {:"$1", :"$2"},
+            [{:"=<", :"$1", {:const, current_time}}],
+            [:"$_"]
+          }
+        ],
+        desired
+      )
+
+    popped
+    |> Enum.each(fn e ->
+      :ets.delete_object(table, e)
+    end)
+
+    popped
+  end
+
+  def maybe_start_job(running_jobs, queue_table) do
+    # we don't want to hit the ets or the DateTime more times than we have to
+    # could optimize slightly further by not using the count, and instead grabbing
+    # up to N objects early...
+    current_time = DateTime.to_unix(DateTime.utc_now())
+    n_running_jobs = :sets.size(running_jobs)
+
+    if n_running_jobs < Pleroma.Config.get([__MODULE__, :max_jobs]) do
+      n_ready_jobs = ets_count_expires(queue_table, current_time)
+
+      if n_ready_jobs > 0 do
+        # figure out how many we could start
+        available_job_slots = Pleroma.Config.get([__MODULE__, :max_jobs]) - n_running_jobs
+        start_n_jobs(running_jobs, queue_table, current_time, available_job_slots)
+      else
+        running_jobs
+      end
+    else
+      running_jobs
+    end
+  end
+
+  defp start_n_jobs(running_jobs, _queue_table, _current_time, 0) do
+    running_jobs
+  end
+
+  defp start_n_jobs(running_jobs, queue_table, current_time, available_job_slots)
+       when available_job_slots > 0 do
+    candidates = ets_pop_n_expired(queue_table, current_time, available_job_slots)
+
+    candidates
+    |> List.foldl(running_jobs, fn {_, e}, rj ->
+      {:ok, pid} = Task.start(fn -> worker(e) end)
+      mref = Process.monitor(pid)
+      :sets.add_element(mref, rj)
+    end)
+  end
+
+  def worker({:send, data, transport, retries}) do
+    case transport.publish_one(data) do
+      {:ok, _} ->
+        GenServer.cast(__MODULE__, :inc_delivered)
+        :delivered
+
+      {:error, _reason} ->
+        enqueue(data, transport, retries)
+        :retry
+    end
+  end
+
+  def handle_call(:get_stats, _from, %{delivered: delivery_count, dropped: drop_count} = state) do
+    {:reply, %{delivered: delivery_count, dropped: drop_count}, state}
+  end
+
+  def handle_call(:reset_stats, _from, %{delivered: delivery_count, dropped: drop_count} = state) do
+    {:reply, %{delivered: delivery_count, dropped: drop_count},
+     %{state | delivered: 0, dropped: 0}}
+  end
+
+  def handle_cast(:reset_stats, state) do
+    {:noreply, %{state | delivered: 0, dropped: 0}}
+  end
+
+  def handle_cast(
+        {:maybe_enqueue, data, transport, retries},
+        %{dropped: drop_count, queue_table: queue_table, running_jobs: running_jobs} = state
+      ) do
     case get_retry_params(retries) do
       {:retry, timeout} ->
-        Process.send_after(
-          __MODULE__,
-          {:send, data, transport, retries},
-          growth_function(retries)
-        )
-
-        {:noreply, state}
+        :ets.insert(queue_table, {timeout, {:send, data, transport, retries}})
+        running_jobs = maybe_start_job(running_jobs, queue_table)
+        {:noreply, %{state | running_jobs: running_jobs}}
 
       {:drop, message} ->
         Logger.debug(message)
@@ -49,23 +173,65 @@ defmodule Pleroma.Web.Federator.RetryQueue do
     end
   end
 
+  def handle_cast(:kickoff_timer, state) do
+    retry_interval = get_retry_timer_interval()
+    Process.send_after(__MODULE__, :retry_timer_run, retry_interval)
+    {:noreply, state}
+  end
+
+  def handle_cast(:inc_delivered, %{delivered: delivery_count} = state) do
+    {:noreply, %{state | delivered: delivery_count + 1}}
+  end
+
+  def handle_cast(:inc_dropped, %{dropped: drop_count} = state) do
+    {:noreply, %{state | dropped: drop_count + 1}}
+  end
+
   def handle_info({:send, data, transport, retries}, %{delivered: delivery_count} = state) do
     case transport.publish_one(data) do
       {:ok, _} ->
         {:noreply, %{state | delivered: delivery_count + 1}}
 
-      {:error, reason} ->
+      {:error, _reason} ->
         enqueue(data, transport, retries)
         {:noreply, state}
     end
   end
 
+  def handle_info(
+        :retry_timer_run,
+        %{queue_table: queue_table, running_jobs: running_jobs} = state
+      ) do
+    maybe_kickoff_timer()
+    running_jobs = maybe_start_job(running_jobs, queue_table)
+    {:noreply, %{state | running_jobs: running_jobs}}
+  end
+
+  def handle_info({:DOWN, ref, :process, _pid, _reason}, state) do
+    %{running_jobs: running_jobs, queue_table: queue_table} = state
+    running_jobs = :sets.del_element(ref, running_jobs)
+    running_jobs = maybe_start_job(running_jobs, queue_table)
+    {:noreply, %{state | running_jobs: running_jobs}}
+  end
+
   def handle_info(unknown, state) do
     Logger.debug("RetryQueue: don't know what to do with #{inspect(unknown)}, ignoring")
     {:noreply, state}
   end
 
-  defp growth_function(retries) do
-    round(@initial_timeout * :math.pow(retries, 3))
+  if Mix.env() == :test do
+    defp growth_function(_retries) do
+      _shutit = Pleroma.Config.get([__MODULE__, :initial_timeout])
+      DateTime.to_unix(DateTime.utc_now()) - 1
+    end
+  else
+    defp growth_function(retries) do
+      round(Pleroma.Config.get([__MODULE__, :initial_timeout]) * :math.pow(retries, 3)) +
+        DateTime.to_unix(DateTime.utc_now())
+    end
+  end
+
+  defp maybe_kickoff_timer do
+    GenServer.cast(__MODULE__, :kickoff_timer)
   end
 end