From b4ff63d020293bd633bc9c01af1078cacf7f90ed Mon Sep 17 00:00:00 2001
From: Alexander Strizhakov <alex.strizhakov@gmail.com>
Date: Sat, 9 Jan 2021 18:52:40 +0300
Subject: [PATCH] configurable limits for ConcurrentLimiter

Pleroma.Web.RichMedia.Helpers & Pleroma.Web.MediaProxy
---
 config/config.exs                |  5 +++++
 config/description.exs           | 48 ++++++++++++++++++++++++++++++++++++++++
 docs/configuration/cheatsheet.md | 12 ++++++++++
 lib/pleroma/application.ex       | 11 ++++++++-
 4 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/config/config.exs b/config/config.exs
index 70d0c2c2b..e07e67de9 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -832,6 +832,11 @@ config :pleroma, Pleroma.User.Backup,
   limit_days: 7,
   dir: nil
 
+config :pleroma, ConcurrentLimiter, [
+  {Pleroma.Web.RichMedia.Helpers, [max_running: 5, max_waiting: 5]},
+  {Pleroma.Web.MediaProxy, [max_running: 5, max_waiting: 5]}
+]
+
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{Mix.env()}.exs"
diff --git a/config/description.exs b/config/description.exs
index 493d362d3..49fea4234 100644
--- a/config/description.exs
+++ b/config/description.exs
@@ -3330,5 +3330,53 @@ config :pleroma, :config_description, [
         suggestions: [:text, :protobuf]
       }
     ]
+  },
+  %{
+    group: :pleroma,
+    key: ConcurrentLimiter,
+    type: :group,
+    description: "Limits configuration for background tasks.",
+    children: [
+      %{
+        key: Pleroma.Web.RichMedia.Helpers,
+        type: :keyword,
+        description: "Concurrent limits configuration for getting RichMedia for activities.",
+        suggestions: [max_running: 5, max_waiting: 5],
+        children: [
+          %{
+            key: :max_running,
+            type: :integer,
+            description: "Max running concurrently jobs.",
+            suggestion: [5]
+          },
+          %{
+            key: :max_waiting,
+            type: :integer,
+            description: "Max waiting jobs.",
+            suggestion: [5]
+          }
+        ]
+      },
+      %{
+        key: Pleroma.Web.MediaProxy,
+        type: :keyword,
+        description: "Concurrent limits configuration for MediaProxyWarmingPolicy.",
+        suggestions: [max_running: 5, max_waiting: 5],
+        children: [
+          %{
+            key: :max_running,
+            type: :integer,
+            description: "Max running concurrently jobs.",
+            suggestion: [5]
+          },
+          %{
+            key: :max_waiting,
+            type: :integer,
+            description: "Max waiting jobs.",
+            suggestion: [5]
+          }
+        ]
+      }
+    ]
   }
 ]
diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index c7d8a2dae..c7ff8687e 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -1110,3 +1110,15 @@ Settings to enable and configure expiration for ephemeral activities
 
 * `:enabled` - enables ephemeral activities creation
 * `:min_lifetime` - minimum lifetime for ephemeral activities (in seconds). Default: 10 minutes.
+
+## ConcurrentLimiter
+
+Settings allow configuring restrictions for concurrently running jobs. Jobs, which can be configured:
+
+* `Pleroma.Web.RichMedia.Helpers` - configuration for getting RichMedia for activities.
+* `Pleroma.Web.MediaProxy` - configuration for MediaProxyWarmingPolicy.
+
+Each job has these settings:
+
+* `:max_running` - max concurrently runnings jobs
+* `:max_waiting` - max waiting jobs
diff --git a/lib/pleroma/application.ex b/lib/pleroma/application.ex
index 203a95004..4742a3ecb 100644
--- a/lib/pleroma/application.ex
+++ b/lib/pleroma/application.ex
@@ -297,7 +297,16 @@ defmodule Pleroma.Application do
 
   @spec limiters_setup() :: :ok
   def limiters_setup do
+    config = Config.get(ConcurrentLimiter, [])
+
     [Pleroma.Web.RichMedia.Helpers, Pleroma.Web.MediaProxy]
-    |> Enum.each(&ConcurrentLimiter.new(&1, 1, 0))
+    |> Enum.each(fn module ->
+      mod_config = Keyword.get(config, module, [])
+
+      max_running = Keyword.get(mod_config, :max_running, 5)
+      max_waiting = Keyword.get(mod_config, :max_waiting, 5)
+
+      ConcurrentLimiter.new(module, max_running, max_waiting)
+    end)
   end
 end