Preventing yourself from accidentally breaking production with Drush

For all the sites I maintain, I have at least a local and production environment. Some projects warrant a dev, qa, etc. as well, but for the purposes of this post, let's just assume you often run drush commands on local or development environments during development, and eventually run a similar command on production during a deployment.

What happens if, at some point, you are churning through some Drush commands, using aliases (e.g. drush @site.local break-all-the-things to break things for testing), and you accidentally enter @site.prod instead of @site.local? Or what if you were doing something potentially disastrous, like deleting a database table locally so you can test a module install file, using drush sqlq to run a query?

$ drush @site.prod break-all-the-things -y
Everything is broken!                                    [sadpanda]

Most potentially-devastating drush commands will ask for confirmation (which could be overridden with a -y in the command), but I like having an extra layer of protection to make sure I don't do something dumb. If you use Bash for your shell session, you can put the following into your .profile or .bash_profile, and Bash will warn you whenever the string .prod is in one of your commands:

prod_command_trap () {
  if [[ $BASH_COMMAND == *.prod* ]]
  then
    read -p "Are you sure you want to run this command on prod [Y/n]? " -n 1 -r
    if [[ $REPLY =~ ^[Yy]$ ]]
    then
      echo -e "\nRunning command \"$BASH_COMMAND\" \n"
    else
      echo -e "\nCommand was not run.\n"
      return 1
    fi
  fi
}
shopt -s extdebug
trap prod_command_trap DEBUG

Now if I accidentally run a command on production I get a warning/confirmation before the command is run:

$ drush @site.prod break-all-the-things -y
Are you sure you want to run this command on prod [Y/n]?

This code, as well as other aliases and configuration I use to help my command-line usage more efficient, is also viewable in my Dotfiles repository on GitHub.