bootstrap

#!/bin/bash

# bootstrap: Script to resolve all dependencies that the application requires to run.
#

# Drop out if one of the commands fails
set -e

# Common function to output important messages
function output_message {
  message=$1
  if [[ -z $message ]]
  then
    echo "output_message called without a message?"
    exit
  fi

  echo
  echo "==> $message"
}

output_message "Bootstrapping dependencies…"

# Ensure we are working from the top of the project
cd "$(dirname "$0")/../.."
echo "Change directory to: $(pwd)"

# Install linux distro specific packages
package_manager=unknown
packages_updated=false

function update_packages {
  if [[ $packages_updated = true ]]
  then
    return
  fi

  case $package_manager in
    apt)
      output_message "Updating apt packages…"
      sudo apt update
      sudo apt -y upgrade
      sudo apt -y auto-remove
      ;;
    yum)
      output_message "Updating yum packages…"
      sudo yum update
      ;;
  esac
  packages_updated=true
}

function install_apt_packages {
  if [[ -f apt-packages ]]
  then
    update_packages
    output_message "Installing apt packages…"
    # We need word splitting to install multiple packages on a single line
    # shellcheck disable=SC2046
    sudo apt -y install $(< apt-packages)
  fi
}

function install_yum_packages {
  if [[ -f yum-packages ]]
  then
    update_packages
    output_message "Installing yum packages…"
    # We need word splitting to install multiple packages on a single line
    # shellcheck disable=SC2046
    sudo yum -y install $(< yum-packages)
  fi
}

function install_linux_packages {
  case $package_manager in
    apt)
      install_apt_packages
      ;;
    yum)
      install_yum_packages
      ;;
    *)
      echo "Not sure which package manager this distro uses so cannot install packages"
      ;;
  esac
}

# Check whether this is Windows Subsystem for Linux
is_wsl=false
if uname -a | grep -q "icrosoft"
then
  is_wsl=true
fi

# Work out what type of OS we are running on
is_linux=false
is_mac=false
if [[ $(uname -s) = "Linux" ]]
then
  echo "This appears to be a Linux based system"
  is_linux=true

  # shellcheck disable=SC1091
  . /etc/os-release

  distro=$ID
  echo -n "Current distro is: $distro"
  if [[ $is_wsl = true ]]
  then
    echo -n " (WSL)"
  fi
  echo

  case $distro in
    centos | rhel | fedora)
      package_manager=yum
      ;;
    ubuntu | debian)
      package_manager=apt
      ;;
  esac
  install_linux_packages
elif [[ $(uname -s) = "Darwin" ]]
then
  echo "This appears to be a Mac"
  is_mac=true
else
  echo "This script only runs on Linux or Mac systems"
  exit 1
fi

# If Brewfile exists then make sure dependencies are all installed and up to date
if [[ -f Brewfile ]]
then
  if command -v brew > /dev/null
  then
    output_message "Updating Homebrew…"
    brew update
  else
    output_message "Installing Homebrew…"
    bash <(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)

    if [[ $is_linux = true ]]
    then
      # Install recommended packages
      update_packages
      case $package_manager in
        apt)
          sudo apt -y install build-essential
          ;;
        yum)
          sudo yum -y groupinstall 'Development Tools'
          ;;
      esac

      # Add Homebrew environment variables to current shell
      eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"

      # Add Homebrew environment variables to local users profile
      {
        echo
        echo "# Homebrew environment variables"
        /home/linuxbrew/.linuxbrew/bin/brew shellenv
      } >> "$HOME/.bashrc"
    elif [[ $is_mac = true ]]
    then
      echo "TODO - automatic install of Homebrew on a Mac???"
    fi

    # Install gcc as recommended in the next steps
    brew install gcc
  fi

  if brew bundle check > /dev/null 2>&1
  then
    echo "Homebrew dependencies are up to date"
  else
    output_message "Installing Homebrew dependencies…"
    brew bundle
  fi
fi