commit: 0ac010ba3fa41c9bd06565259de57f2a5b5bb8ad
parent 548434f85ccaa4a77c460fb5bda37153ea6e9c39
Author: Mark Felder <feld@feld.me>
Date: Mon, 22 Jan 2024 10:01:29 -0500
Replace custom fifo implementation with Exile
This is for streaming media to ffmpeg thumbnailer. The existing implementation relies on undocumented behavior.
Erlang open_port/2 does not officially support passing a string of a file path for opening. The specs clearly state you are to provide one of the following for open_port/2:
{spawn, Command :: string() | binary()} |
{spawn_driver, Command :: string() | binary()} |
{spawn_executable, FileName :: file:name_all()} |
{fd, In :: integer() >= 0, Out :: integer() >= 0}
Our method technically works but is strongly discouraged as it can block the scheduler and dialyzer throws errors as it recognizes we're breaking the contract and some of the functions we wrote may never return.
This is indirectly covered by the Erlang FAQ section "9.12 Why can't I open devices (e.g. a serial port) like normal files?"
https://www.erlang.org/faq/problems#idm1127
Diffstat:
4 files changed, 21 insertions(+), 80 deletions(-)
diff --git a/changelog.d/exile.skip b/changelog.d/exile.skip
diff --git a/lib/pleroma/helpers/media_helper.ex b/lib/pleroma/helpers/media_helper.ex
@@ -43,89 +43,28 @@ defmodule Pleroma.Helpers.MediaHelper do
def video_framegrab(url) do
with executable when is_binary(executable) <- System.find_executable("ffmpeg"),
{:ok, env} <- HTTP.get(url, [], pool: :media),
- {:ok, fifo_path} <- mkfifo(),
- args = [
- "-y",
- "-i",
- fifo_path,
- "-vframes",
- "1",
- "-f",
- "mjpeg",
- "-loglevel",
- "error",
- "-"
- ] do
- run_fifo(fifo_path, env, executable, args)
+ {:ok, pid} <- StringIO.open(env.body) do
+ body_stream = IO.binstream(pid, 1)
+
+ Exile.stream!(
+ [
+ executable,
+ "-i",
+ "pipe:0",
+ "-vframes",
+ "1",
+ "-f",
+ "mjpeg",
+ "pipe:1"
+ ],
+ input: body_stream,
+ ignore_epipe: true,
+ stderr: :disable
+ )
+ |> Enum.into(<<>>)
else
nil -> {:error, {:ffmpeg, :command_not_found}}
{:error, _} = error -> error
end
end
-
- defp run_fifo(fifo_path, env, executable, args) do
- pid =
- Port.open({:spawn_executable, executable}, [
- :use_stdio,
- :stream,
- :exit_status,
- :binary,
- args: args
- ])
-
- fifo = Port.open(to_charlist(fifo_path), [:eof, :binary, :stream, :out])
- fix = Pleroma.Helpers.QtFastStart.fix(env.body)
- true = Port.command(fifo, fix)
- :erlang.port_close(fifo)
- loop_recv(pid)
- after
- File.rm(fifo_path)
- end
-
- defp mkfifo do
- path = Path.join(System.tmp_dir!(), "pleroma-media-preview-pipe-#{Ecto.UUID.generate()}")
-
- case System.cmd("mkfifo", [path]) do
- {_, 0} ->
- spawn(fifo_guard(path))
- {:ok, path}
-
- {_, err} ->
- {:error, {:fifo_failed, err}}
- end
- end
-
- defp fifo_guard(path) do
- pid = self()
-
- fn ->
- ref = Process.monitor(pid)
-
- receive do
- {:DOWN, ^ref, :process, ^pid, _} ->
- File.rm(path)
- end
- end
- end
-
- defp loop_recv(pid) do
- loop_recv(pid, <<>>)
- end
-
- defp loop_recv(pid, acc) do
- receive do
- {^pid, {:data, data}} ->
- loop_recv(pid, acc <> data)
-
- {^pid, {:exit_status, 0}} ->
- {:ok, acc}
-
- {^pid, {:exit_status, status}} ->
- {:error, status}
- after
- 5000 ->
- :erlang.port_close(pid)
- {:error, :timeout}
- end
- end
end
diff --git a/mix.exs b/mix.exs
@@ -184,6 +184,7 @@ defmodule Pleroma.Mixfile do
{:vix, "~> 0.26.0"},
{:elixir_make, "~> 0.7.7", override: true},
{:blurhash, "~> 0.1.0", hex: :rinpatch_blurhash},
+ {:exile, "~> 0.8.0"},
## dev & test
{:ex_doc, "~> 0.22", only: :dev, runtime: false},
diff --git a/mix.lock b/mix.lock
@@ -46,6 +46,7 @@
"ex_doc": {:hex, :ex_doc, "0.29.4", "6257ecbb20c7396b1fe5accd55b7b0d23f44b6aa18017b415cb4c2b91d997729", [:mix], [{:earmark_parser, "~> 1.4.31", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "2c6699a737ae46cb61e4ed012af931b57b699643b24dabe2400a8168414bc4f5"},
"ex_machina": {:hex, :ex_machina, "2.7.0", "b792cc3127fd0680fecdb6299235b4727a4944a09ff0fa904cc639272cd92dc7", [:mix], [{:ecto, "~> 2.2 or ~> 3.0", [hex: :ecto, repo: "hexpm", optional: true]}, {:ecto_sql, "~> 3.0", [hex: :ecto_sql, repo: "hexpm", optional: true]}], "hexpm", "419aa7a39bde11894c87a615c4ecaa52d8f107bbdd81d810465186f783245bf8"},
"ex_syslogger": {:hex, :ex_syslogger, "1.5.2", "72b6aa2d47a236e999171f2e1ec18698740f40af0bd02c8c650bf5f1fd1bac79", [:mix], [{:poison, ">= 1.5.0", [hex: :poison, repo: "hexpm", optional: true]}, {:syslog, "~> 1.1.0", [hex: :syslog, repo: "hexpm", optional: false]}], "hexpm", "ab9fab4136dbc62651ec6f16fa4842f10cf02ab4433fa3d0976c01be99398399"},
+ "exile": {:hex, :exile, "0.8.0", "7287f76add343c5dcf5e5b46066ebb93b02b7e643cce7a1a1c5eab3e7d9eb5d8", [:make, :mix], [{:elixir_make, "~> 0.6", [hex: :elixir_make, repo: "hexpm", optional: false]}], "hexpm", "63309c36590f3a524f513255601404e6672be4c8bea0cc4420fbae02e7ffffac"},
"expo": {:hex, :expo, "0.4.1", "1c61d18a5df197dfda38861673d392e642649a9cef7694d2f97a587b2cfb319b", [:mix], [], "hexpm", "2ff7ba7a798c8c543c12550fa0e2cbc81b95d4974c65855d8d15ba7b37a1ce47"},
"fast_html": {:hex, :fast_html, "2.0.5", "c61760340606c1077ff1f196f17834056cb1dd3d5cb92a9f2cabf28bc6221c3c", [:make, :mix], [{:elixir_make, "~> 0.4", [hex: :elixir_make, repo: "hexpm", optional: false]}, {:nimble_pool, "~> 0.2.0", [hex: :nimble_pool, repo: "hexpm", optional: false]}], "hexpm", "605f4f4829443c14127694ebabb681778712ceecb4470ec32aa31012330e6506"},
"fast_sanitize": {:hex, :fast_sanitize, "0.2.3", "67b93dfb34e302bef49fec3aaab74951e0f0602fd9fa99085987af05bd91c7a5", [:mix], [{:fast_html, "~> 2.0", [hex: :fast_html, repo: "hexpm", optional: false]}, {:plug, "~> 1.8", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "e8ad286d10d0386e15d67d0ee125245ebcfbc7d7290b08712ba9013c8c5e56e2"},
