From 84b183dd5190d2ea540147d662d140279b216d61 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonatan=20K=C5=82osko?= <jonatanklosko@gmail.com>
Date: Thu, 13 Jun 2024 18:03:28 +0200
Subject: [PATCH] Defer distribution boot in releases (#2648)

---
 README.md                         |  6 ++++--
 elixirkit/lib/elixirkit/server.ex |  2 +-
 lib/livebook.ex                   |  4 +---
 rel/app/env.bat.eex               | 20 ++++++++------------
 rel/app/env.sh.eex                | 23 +++++++++++------------
 rel/app/vm.args.eex               |  3 ++-
 rel/server/env.bat.eex            | 23 +++++++++--------------
 rel/server/env.sh.eex             | 31 +++++++++++++++++++------------
 8 files changed, 55 insertions(+), 57 deletions(-)

diff --git a/README.md b/README.md
index ee7f19feb..565cc2312 100644
--- a/README.md
+++ b/README.md
@@ -256,8 +256,10 @@ The following environment variables can be used to configure Livebook on boot:
   * `LIVEBOOK_IP` - sets the ip address to start the web application on.
     Must be a valid IPv4 or IPv6 address.
 
-  * `LIVEBOOK_NODE` - sets the node name for running Livebook in a cluster. Note that
-    this sets RELEASE_NODE if present when creating a release.
+  * `LIVEBOOK_NODE` - sets the node name for running Livebook in a cluster.
+    Note that Livebook always runs using long names distrivution, so the
+    node host name must use a fully qualified domain name (FQDN) or an IP
+    address.
 
   * `LIVEBOOK_PASSWORD` - sets a password that must be used to access Livebook.
     Must be at least 12 characters. Defaults to token authentication.
diff --git a/elixirkit/lib/elixirkit/server.ex b/elixirkit/lib/elixirkit/server.ex
index 56caa9e5c..b1f58e441 100644
--- a/elixirkit/lib/elixirkit/server.ex
+++ b/elixirkit/lib/elixirkit/server.ex
@@ -10,7 +10,7 @@ defmodule ElixirKit.Server do
   @impl true
   def init(pid) do
     port = System.fetch_env!("ELIXIRKIT_PORT") |> String.to_integer()
-    {:ok, socket} = :gen_tcp.connect('localhost', port, mode: :binary, packet: 4)
+    {:ok, socket} = :gen_tcp.connect(~c"localhost", port, mode: :binary, packet: 4)
     {:ok, %{pid: pid, socket: socket}}
   end
 
diff --git a/lib/livebook.ex b/lib/livebook.ex
index 7052f8c1e..e207340d9 100644
--- a/lib/livebook.ex
+++ b/lib/livebook.ex
@@ -203,9 +203,7 @@ defmodule Livebook do
 
     config :livebook,
            :cookie,
-           Livebook.Config.cookie!("LIVEBOOK_COOKIE") ||
-             Livebook.Config.cookie!("RELEASE_COOKIE") ||
-             Livebook.Utils.random_cookie()
+           Livebook.Config.cookie!("LIVEBOOK_COOKIE") || Livebook.Utils.random_cookie()
 
     # TODO: remove in v1.0
     if System.get_env("LIVEBOOK_DISTRIBUTION") == "sname" do
diff --git a/rel/app/env.bat.eex b/rel/app/env.bat.eex
index 439c83a65..1c575f7da 100644
--- a/rel/app/env.bat.eex
+++ b/rel/app/env.bat.eex
@@ -6,19 +6,13 @@ if not defined LIVEBOOK_EPMDLESS set LIVEBOOK_EPMDLESS=true
 if "!LIVEBOOK_EPMDLESS!"=="1" goto epmdless
 if "!LIVEBOOK_EPMDLESS!"=="true" goto epmdless
 goto continue
-
 :epmdless
 set ELIXIR_ERL_OPTIONS=!ELIXIR_ERL_OPTIONS! -epmd_module Elixir.Livebook.EPMD -start_epmd false -erl_epmd_port 0
-
 :continue
-for /f "skip=1" %%X in ('wmic os get localdatetime') do if not defined TIMESTAMP set TIMESTAMP=%%X
 
-set RELEASE_DISTRIBUTION="name"
+set RELEASE_MODE="interactive"
+set RELEASE_DISTRIBUTION="none"
 
-if defined LIVEBOOK_NODE set RELEASE_NODE=!LIVEBOOK_NODE!
-if not defined RELEASE_NODE set RELEASE_NODE=livebook-app-!TIMESTAMP:~8,6!-!RANDOM!
-
-set RELEASE_MODE=interactive
 set MIX_ARCHIVES=!RELEASE_ROOT!\vendor\archives
 set MIX_REBAR3=!RELEASE_ROOT!\vendor\rebar3
 if not defined LIVEBOOK_SHUTDOWN_ENABLED set LIVEBOOK_SHUTDOWN_ENABLED=true
@@ -26,10 +20,12 @@ set LIVEBOOK_DESKTOP=true
 if not defined LIVEBOOK_PORT (set LIVEBOOK_PORT=0)
 set PATH=!RELEASE_ROOT!\vendor\otp\erts-<%= @release.erts_version%>\bin;!RELEASE_ROOT!\vendor\otp\bin;!RELEASE_ROOT!\vendor\elixir\bin;!PATH!
 
-set cookie_path=!RELEASE_ROOT!\releases\COOKIE
-if not exist %cookie_path% (
-  :: '| set /p=""' is so that we don't add ' \r\n' to the cookie
-  echo | set /p="cookie-!TIMESTAMP:~0,11!-!RANDOM!" > %cookie_path%
+if defined LIVEBOOK_NODE set RELEASE_NODE=!LIVEBOOK_NODE!
+if defined LIVEBOOK_COOKIE set RELEASE_COOKIE=!LIVEBOOK_COOKIE!
+
+if not defined RELEASE_COOKIE (
+  for /f "skip=1" %%X in ('wmic os get localdatetime') do if not defined TIMESTAMP set TIMESTAMP=%%X
+  set RELEASE_COOKIE=cookie-!TIMESTAMP:~0,11!-!RANDOM!
 )
 
 cd !HOMEDRIVE!!HOMEPATH!
diff --git a/rel/app/env.sh.eex b/rel/app/env.sh.eex
index eaebd1668..51a377f52 100644
--- a/rel/app/env.sh.eex
+++ b/rel/app/env.sh.eex
@@ -2,25 +2,24 @@ if [ -f "$HOME/.livebookdesktop.sh" ]; then
   . "$HOME/.livebookdesktop.sh"
 fi
 
-export RELEASE_DISTRIBUTION="name"
-export RELEASE_NODE=${LIVEBOOK_NODE:-${RELEASE_NODE:-"livebook-app-$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 8 | head -n 1)"}}
-export RELEASE_MODE=interactive
+export LIVEBOOK_EPMDLESS=${LIVEBOOK_EPMDLESS:-true}
+if [ "$LIVEBOOK_EPMDLESS" = "true" ] || [ "$LIVEBOOK_EPMDLESS" = "1" ]; then
+  export ELIXIR_ERL_OPTIONS="${ELIXIR_ERL_OPTIONS} -epmd_module Elixir.Livebook.EPMD -start_epmd false -erl_epmd_port 0"
+fi
+
+export RELEASE_MODE="interactive"
+export RELEASE_DISTRIBUTION="none"
+
 export MIX_ARCHIVES="${RELEASE_ROOT}/vendor/archives"
 export MIX_REBAR3="${RELEASE_ROOT}/vendor/rebar3"
-export LIVEBOOK_EPMDLESS=${LIVEBOOK_EPMDLESS:-true}
 export LIVEBOOK_SHUTDOWN_ENABLED=${LIVEBOOK_SHUTDOWN_ENABLED:-true}
 export LIVEBOOK_DESKTOP=true
 [ -z "$LIVEBOOK_PORT" ] && export LIVEBOOK_PORT=0
 export PATH="$RELEASE_ROOT/vendor/otp/erts-<%= @release.erts_version%>/bin:$RELEASE_ROOT/vendor/otp/bin:$RELEASE_ROOT/vendor/elixir/bin:$PATH"
 
-if [ "$LIVEBOOK_EPMDLESS" = "true" ] || [ "$LIVEBOOK_EPMDLESS" = "1" ]; then
-  export ELIXIR_ERL_OPTIONS="${ELIXIR_ERL_OPTIONS} -epmd_module Elixir.Livebook.EPMD -start_epmd false -erl_epmd_port 0"
-fi
+if [ ! -z "${LIVEBOOK_NODE}" ]; then export RELEASE_NODE=${LIVEBOOK_NODE}; fi
+if [ ! -z "${LIVEBOOK_COOKIE}" ]; then export RELEASE_COOKIE=${LIVEBOOK_COOKIE}; fi
 
-cookie_path="${RELEASE_ROOT}/releases/COOKIE"
-if [ ! -f $cookie_path ]; then
-  RELEASE_COOKIE=$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
-  echo "$RELEASE_COOKIE" > "$cookie_path" || export RELEASE_COOKIE
-fi
+export RELEASE_COOKIE="${RELEASE_COOKIE:-$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)}"
 
 cd $HOME
diff --git a/rel/app/vm.args.eex b/rel/app/vm.args.eex
index 67880f479..abd39f5ab 100644
--- a/rel/app/vm.args.eex
+++ b/rel/app/vm.args.eex
@@ -1,2 +1,3 @@
 # Disable busy waiting so that we don't waste resources
-+sbwt none +sbwtdcpu none +sbwtdio none
+# Limit the maximal number of ports for the same reason
++sbwt none +sbwtdcpu none +sbwtdio none +Q 65536
diff --git a/rel/server/env.bat.eex b/rel/server/env.bat.eex
index 3def5c56b..f6677c291 100644
--- a/rel/server/env.bat.eex
+++ b/rel/server/env.bat.eex
@@ -5,22 +5,17 @@ if exist "!RELEASE_ROOT!\user\env.bat" (
 if "!LIVEBOOK_EPMDLESS!"=="1" goto epmdless
 if "!LIVEBOOK_EPMDLESS!"=="true" goto epmdless
 goto continue
-
 :epmdless
 set ELIXIR_ERL_OPTIONS=!ELIXIR_ERL_OPTIONS! -epmd_module Elixir.Livebook.EPMD -start_epmd false -erl_epmd_port 0
-
 :continue
-set RELEASE_MODE=interactive
-if defined LIVEBOOK_NODE set RELEASE_NODE="!LIVEBOOK_NODE!"
-if not defined RELEASE_NODE set RELEASE_NODE=livebook_server
-set RELEASE_DISTRIBUTION="name"
 
-if defined LIVEBOOK_COOKIE set RELEASE_COOKIE="!LIVEBOOK_COOKIE!"
-set cookie_path="!RELEASE_ROOT!\releases\COOKIE"
-if not exist %cookie_path% (
-  if not defined RELEASE_COOKIE (
-    for /f "skip=1" %%X in ('wmic os get localdatetime') do if not defined TIMESTAMP set TIMESTAMP=%%X
-    :: '| set /p=""' is so that we don't add ' \r\n' to the cookie
-    echo | set /p="cookie-!TIMESTAMP:~0,11!-!RANDOM!" > %cookie_path%
-  )
+set RELEASE_MODE="interactive"
+set RELEASE_DISTRIBUTION="none"
+
+if defined LIVEBOOK_NODE set RELEASE_NODE=!LIVEBOOK_NODE!
+if defined LIVEBOOK_COOKIE set RELEASE_COOKIE=!LIVEBOOK_COOKIE!
+
+if not defined RELEASE_COOKIE (
+  for /f "skip=1" %%X in ('wmic os get localdatetime') do if not defined TIMESTAMP set TIMESTAMP=%%X
+  set RELEASE_COOKIE=cookie-!TIMESTAMP:~0,11!-!RANDOM!
 )
diff --git a/rel/server/env.sh.eex b/rel/server/env.sh.eex
index 6cc564e6e..7b2a03d08 100644
--- a/rel/server/env.sh.eex
+++ b/rel/server/env.sh.eex
@@ -1,26 +1,33 @@
-NODE_DEFAULT="livebook_server"
-
 if [ "$LIVEBOOK_CLUSTER" = "fly" ]; then
   export ERL_AFLAGS="-proto_dist inet6_tcp"
   export LIVEBOOK_CLUSTER="dns:${FLY_APP_NAME}.internal"
-  NODE_DEFAULT="${FLY_APP_NAME}-${FLY_IMAGE_REF##*-}@${FLY_PRIVATE_IP}"
+  if [ ! -z "${LIVEBOOK_NODE}" ];
+    then export LIVEBOOK_NODE="${FLY_APP_NAME}-${FLY_IMAGE_REF##*-}@${FLY_PRIVATE_IP}";
+  fi
 fi
 
 if [ -f "${RELEASE_ROOT}/user/env.sh" ]; then
   . "${RELEASE_ROOT}/user/env.sh"
 fi
 
-export RELEASE_MODE=interactive
-export RELEASE_NODE=${LIVEBOOK_NODE:-${RELEASE_NODE:-${NODE_DEFAULT}}}
-export RELEASE_DISTRIBUTION="name"
-
 if [ "$LIVEBOOK_EPMDLESS" = "true" ] || [ "$LIVEBOOK_EPMDLESS" = "1" ]; then
   export ELIXIR_ERL_OPTIONS="${ELIXIR_ERL_OPTIONS} -epmd_module Elixir.Livebook.EPMD -start_epmd false -erl_epmd_port 0"
 fi
 
+export RELEASE_MODE="interactive"
+export RELEASE_DISTRIBUTION="none"
+
+# Mirror these values, so that it is easier to use "bin/release rpc",
+# though it still requires setting RELEASE_DISTRIBUTION=name
+if [ ! -z "${LIVEBOOK_NODE}" ]; then export RELEASE_NODE=${LIVEBOOK_NODE}; fi
 if [ ! -z "${LIVEBOOK_COOKIE}" ]; then export RELEASE_COOKIE=${LIVEBOOK_COOKIE}; fi
-cookie_path="${RELEASE_ROOT}/releases/COOKIE"
-if [ ! -f $cookie_path ] && [ -z "$RELEASE_COOKIE" ]; then
-  RELEASE_COOKIE=$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)
-  echo "$RELEASE_COOKIE" > "$cookie_path" || export RELEASE_COOKIE
-fi
+
+# We remove the COOKIE file when assembling the release, because we
+# don't want to share the same cookie across users. The Elixir release
+# script attempts to read from that file, which would fail, therefore
+# we need to set it here. Also there is a very tiny time gap between we
+# start distribution and set the cookie during application boot, so we
+# specifically want the temporary node cookie to be random, rather than
+# a fixed value. Note that this value is overriden on boot, so other
+# than being the initial node cookie, we don't really use it.
+export RELEASE_COOKIE="${RELEASE_COOKIE:-$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)}"