[#2497] Customized `exexec` launch to support root operation (currently required by Gitlab CI).

.gitlab-ci.yml

@@ -6,6 +6,7 @@ variables: &global_variables
   POSTGRES_PASSWORD: postgres
   DB_HOST: postgres
   MIX_ENV: test
+  USER: root
 
 cache: &global_cache_policy
   key: ${CI_COMMIT_REF_SLUG}

config/config.exs

@@ -681,6 +681,10 @@
 
 config :pleroma, Pleroma.Web.ApiSpec.CastAndValidate, strict: false
 
+config :pleroma, :exexec,
+  root_mode: false,
+  options: %{}
+
 # 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"

lib/pleroma/exec.ex

+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Exec do
+  @moduledoc "Pleroma wrapper around Exexec commands."
+
+  alias Pleroma.Config
+
+  def ensure_started(options_overrides \\ %{}) do
+    options =
+      if Config.get([:exexec, :root_mode]) || System.get_env("USER") == "root" do
+        # Note: running as `root` is discouraged (yet Gitlab CI does that by default)
+        %{root: true, user: "root", limit_users: ["root"]}
+      else
+        %{}
+      end
+
+    options =
+      options
+      |> Map.merge(Config.get([:exexec, :options], %{}))
+      |> Map.merge(options_overrides)
+
+    with {:error, {:already_started, pid}} <- Exexec.start(options) do
+      {:ok, pid}
+    end
+  end
+
+  def run(cmd, options \\ %{}) do
+    ensure_started()
+    Exexec.run(cmd, options)
+  end
+
+  def cmd(cmd, options \\ %{}) do
+    options = Map.merge(%{sync: true, stdout: true}, options)
+    run(cmd, options)
+  end
+end

lib/pleroma/helpers/media_helper.ex

@@ -7,8 +7,6 @@ defmodule Pleroma.Helpers.MediaHelper do
   Handles common media-related operations.
   """
 
-  @ffmpeg_opts [{:sync, true}, {:stdout, true}]
-
   def ffmpeg_resize_remote(uri, %{max_width: max_width, max_height: max_height}) do
     cmd = ~s"""
     curl -L "#{uri}" |
@@ -20,7 +18,7 @@ def ffmpeg_resize_remote(uri, %{max_width: max_width, max_height: max_height}) d
     cat
     """
 
-    with {:ok, [stdout: stdout_list]} <- Exexec.run(cmd, @ffmpeg_opts) do
+    with {:ok, [stdout: stdout_list]} <- Pleroma.Exec.cmd(cmd) do
       {:ok, Enum.join(stdout_list)}
     end
   end

mix.exs

@@ -197,7 +197,8 @@ defp deps do
        ref: "e0f16822d578866e186a0974d65ad58cddc1e2ab"},
       {:mox, "~> 0.5", only: :test},
       {:restarter, path: "./restarter"},
-      {:exexec, "~> 0.2"},
+      # Note: `runtime: true` for :exexec makes CI fail due to `root` user (see Pleroma.Exec)
+      {:exexec, "~> 0.2", runtime: false},
       {:open_api_spex,
        git: "https://git.pleroma.social/pleroma/elixir-libraries/open_api_spex.git",
        ref: "f296ac0924ba3cf79c7a588c4c252889df4c2edd"}

test/exec_test.exs

+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.ExecTest do
+  alias Pleroma.Exec
+
+  use Pleroma.DataCase
+
+  test "it starts" do
+    assert {:ok, _} = Exec.ensure_started()
+  end
+end