hot-swap

#!/bin/bash

# This script assumes you have an app running on 2 ports 4040 and 4041 
# and that you can restart your app with a single command

APP_RESTART_COMMAND="/your/app/control restart"

# Find out if the app is running
function app_up {
  port=$1

  # Give the app a minute to boot
  for i in {1..60}
  do
    # Use the app health check url
    curl -fsI 127.0.0.1:$port/okcomputer
    status=$?
    if test "$status" != "0"
    then
      sleep 1
    else
      break
    fi
  done

  return $status
}

# Uncomment any failed attempts at a hot-swap
sudo sed -i -r 's/#+(server 127.0.0.1)/server 127.0.0.1/g' /etc/nginx/nginx.conf

sudo sed -i -r 's/(server 127.0.0.1:4040)/#&/g' /etc/nginx/nginx.conf
sudo /etc/init.d/nginx reload

# Restart the process and let it spin back up
$APP_RESTART_COMMAND 4040

# If the app fails to boot exit this script non-zero
app_up 4040
status=$?
if test "$status" != "0"
then
  exit 1
fi

sudo sed -i -r 's/#(server 127.0.0.1:4040)/server 127.0.0.1:4040/g' /etc/nginx/nginx.conf
sudo /etc/init.d/nginx reload

sudo sed -i -r 's/(server 127.0.0.1:4041)/#&/g' /etc/nginx/nginx.conf
sudo /etc/init.d/nginx reload

# Restart the process and let it spin back up
$APP_RESTART_COMMAND 4041

# If the app fails to boot exit this script non-zero
app_up 4041
status=$?
if test "$status" != "0"
then
  exit 1
fi

sudo sed -i -r 's/#(server 127.0.0.1:4041)/server 127.0.0.1:4041/g' /etc/nginx/nginx.conf
sudo /etc/init.d/nginx reload