Local file watcher to restart docker container.

app-restart-watcher.sh

#!/usr/bin/env bash

restart_app () {
  local app_name="$1"
  # consider pinging the server an only sending this if it is alive?
  docker kill --signal="SIGUSR1" "$app_name" &> /dev/null
}

# Note: using -qq option with inotify will kill all events. So don't do that :p
app_restart_watcher () {
  local app_name="$1"
  local dir_to_watch="$2"
  local pid_file="$3"
  mkdir -p "$(dirname "$pid_file")"
  (echo "$BASHPID" > "$pid_file"; \
    exec inotifywait -q --monitor --recursive --event modify "$dir_to_watch") | \
      while read event; do
        # echo "read event" "$event"
        # echo 'Trying to restart the app ...'
        restart_app "$app_name"
      done
}

Require some watcher for the SIGUSR1 signal.

E.g.

Signal.trap('USR1') do
  # If this signal is triggered before the server is up
  # it will kill the container.
  sleep 3
  puts 'Restarting ...'
  exec("bundle exec ruby #{__FILE__}")  # This replaces the current process with a new version of itself.
end