From 8e4985be246083b89cf11268b94dcb670f63ae3e Mon Sep 17 00:00:00 2001
From: Chris McCord <chris@chrismccord.com>
Date: Fri, 7 Jun 2024 14:58:48 -0400
Subject: [PATCH] Add FLAME support (#2629)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Jonatan Kłosko <jonatanklosko@gmail.com>
Co-authored-by: José Valim <jose.valim@gmail.com>
---
 Dockerfile                              |  2 +-
 rel/server/overlays/bin/server          | 11 +++++++
 rel/server/overlays/bin/start_flame.exs | 38 +++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100755 rel/server/overlays/bin/server
 create mode 100644 rel/server/overlays/bin/start_flame.exs

diff --git a/Dockerfile b/Dockerfile
index 4038253e0..1b6c1995f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -95,4 +95,4 @@ RUN chmod -R go=u $HOME
 
 HEALTHCHECK CMD wget --no-verbose --tries=1 --spider http://localhost:${LIVEBOOK_PORT-8080}/public/health || exit 1
 
-CMD [ "/app/bin/livebook", "start" ]
+CMD [ "/app/bin/server" ]
diff --git a/rel/server/overlays/bin/server b/rel/server/overlays/bin/server
new file mode 100755
index 000000000..0c5d34ff2
--- /dev/null
+++ b/rel/server/overlays/bin/server
@@ -0,0 +1,11 @@
+#!/bin/sh
+set -e
+
+cd -P -- "$(dirname -- "$0")"
+
+if [ -n "${FLAME_PARENT}" ]; then
+  epmd -daemon
+  elixir ./start_flame.exs
+else
+  exec ./livebook start
+fi
diff --git a/rel/server/overlays/bin/start_flame.exs b/rel/server/overlays/bin/start_flame.exs
new file mode 100644
index 000000000..d4135529b
--- /dev/null
+++ b/rel/server/overlays/bin/start_flame.exs
@@ -0,0 +1,38 @@
+flame_parent = System.fetch_env!("FLAME_PARENT") |> Base.decode64!() |> :erlang.binary_to_term()
+
+%{
+  pid: parent_pid,
+  flame_vsn: flame_parent_vsn,
+  backend: _backend,
+  backend_app: backend_app,
+  backend_vsn: backend_vsn,
+  node_base: node_base,
+  host_env: host_env
+} = flame_parent
+
+flame_node_name = :"#{node_base}@#{System.fetch_env!(host_env)}"
+flame_node_cookie = String.to_atom(System.fetch_env!("LIVEBOOK_COOKIE"))
+
+flame_dep =
+  if git_ref = System.get_env("FLAME_GIT_REF") do
+    {:flame, github: "phoenixframework/flame", ref: git_ref}
+  else
+    {:flame, flame_parent_vsn}
+  end
+
+flame_backend_deps =
+  case backend_app do
+    :flame -> []
+    _ -> [{backend_app, backend_vsn}]
+  end
+
+{:ok, _} = :net_kernel.start(flame_node_name, %{name_domain: :longnames})
+Node.set_cookie(flame_node_cookie)
+
+Mix.install([flame_dep | flame_backend_deps], consolidate_protocols: false)
+
+IO.puts(
+  "[Livebook] starting #{inspect(flame_node_name)} in FLAME mode with parent: #{inspect(parent_pid)}, backend: #{inspect(backend_app)}"
+)
+
+System.no_halt(true)