common.sh

#!/usr/bin/env bash

################################################################################
################################################################################
# Name:            common.sh
# Usage:           n/a
# Description:     Common functions useful to the other scripts
# Created:         n/a
# Last Modified:   n/a
################################################################################
################################################################################

# stop the script when an error occurs
# and cause a pipeline (for example, curl -s https://sipb.mit.edu/ | grep foo)
# to produce a failure return code if any command errors.
# Normally, pipelines only return a failure if the last command errors
set -eo pipefail

export DEBIAN_FRONTEND=noninteractive

LOG_DIRECTORY='logs'
LOG_FILE="${LOG_DIRECTORY}/"$(date +%Y-%m-%d).log

# app versions and other useful shortcuts
SDKMAN_URL="https://get.sdkman.io"
JAVA_VERSION_ARCH="jdk8"
JAVA_VERSION_DEBIAN="openjdk-11-jdk"
JAVA_VERSION_FEDORA="java-11-openjdk"
RBENV_REPO="git://github.com/sstephenson/ruby-build.git"
RUBY_VERSION="2.6.1"
RAILS_VERSION="5.2.2"

# Usage: _outputMessage <message>
#
# Outputs <message> to the terminal
# And also logs to the current LOG_FILE value
_outputMessage() {
  if [[ "$#" -ne 1 ]]; then
    _errorExit "Function _outputMessage expected 1 (one) parameter but got $#: '$*'.  Usage: _outputMessage <message>"
  fi

  local fmt="$1"
  shift
  date=$(/bin/date "+%F %T")
  outputMessage="$fmt\n" "$@"
  _logMessage "$outputMessage"
  printf "$date: $outputMessage"
}

# Usage _logMessage <message>
#
# Append string to the end of the timestamped log file
_logMessage() {
  if [[ "$#" -ne 1 ]]; then
    _errorExit "Function _logMessage expected 1 (one) parameter but got $#: '$*'.  Usage: _logMessage <message>"
  fi

  if [[ ! -d "$LOG_DIRECTORY" ]]; then
    mkdir ${LOG_DIRECTORY}
  fi

  if [[ ! -e "$LOG_FILE" ]]; then
    touch "${LOG_FILE}"
  fi

  date=$(/bin/date "+%F %T")

  printf "$date: $1" >>$LOG_FILE 2>&1
}

# Usage: _scriptCompletedMessage
#
# Prints some finishing statistics
# Currently shows how long a script took to run based on when it started
_scriptCompletedMessage() {
  if [[ "$#" -ne 1 ]]; then
    _errorExit "Function _scriptCompletedMessage expected 1 (one) parameter but got $#: '$*'.  Usage: _scriptCompletedMessage <start_time_in_sec>"
  fi

  local start_sec=$1
  local end_sec=$(/bin/date +%s.%N)

  # shellcheck disable=SC2154
  elapsed_seconds=$(echo "$end_sec" "$start_sec" | awk '{ print $1 - $2 }')

  _outputMessage "Finished execution of $(basename "$0") in $elapsed_seconds seconds\n"
}

# Usage: _errorExit <message>
#
# Writes <message> to screen and logfile as a "fatal"
# And immediately exits the currently running script
_errorExit() {
  if [[ "$#" -ne 1 ]]; then
    _outputMessage "[FATAL] Function _errorExit expected 1 (one) parameter but got $#: '$*'.  Usage: _errorExit <message>"
    exit 1
  fi

  local date=$(/bin/date "+%F %T")
  local message=$1

  printf "$date: [FATAL] $message\n" "$@" | tee -a ${LOG_FILE}
  exit 1
}

# Usage: _getLinuxVersion
#
# Determines linux-flavor running on the machine in use
_getLinuxVersion() {
  # Fedora stores the distro id as ID under /etc/os-release
  # Ubuntu and Arch store the distro id as ID_LIKE under /etc/os-release
  #
  # TODO: find how to make this into an elegant one liner
  # $(cat /etc/*-release | grep -we "ID" -we "ID_LIKE" | awk -F '=' '{print $2}')

  if [[ $(grep -r "ID_LIKE" /etc/os-release) ]]; then
    dist=$(grep -w "ID_LIKE" /etc/os-release | awk -F '=' '{print $2}')
  else
    dist=$(grep -w "ID" /etc/os-release | awk -F '=' '{print $2}')
  fi

  echo "$dist"
}

# Usage _ask <question> <response> eg _ask "Install package?" "N"
# https://github.com/minamarkham/formation/blob/master/twirl#L445
#
# Displays a yes/no prompt, and only allows input of Y or N
_ask() {
  if [[ "$#" -ne 2 ]]; then
    _errorExit "Function _ask expected 2 (two) parameters but got $#: '$*'.  Usage: _ask <question> <Y/N>"
  fi

  local prompt default reply

  shopt -s nocasematch
  if [[ "${2}" =~ "y" ]]; then
    prompt="Y/n"
    default=Y
  elif [[ "${2}" =~ "n" ]]; then
    prompt="y/N"
    default=N
  else
    prompt="y/n"
    default=
  fi
  shopt -u nocasematch

  if [[ ${AUTO_ANSWER} ]]; then
    _logMessage " [?] $1 [$prompt]: $default\n"
    case "${2:-}" in
    Y* | y*) return 0 ;;
    N* | n*) return 1 ;;
    esac
  else
    while true; do
      # Ask the question (not using "read -p" as it uses stderr not stdout)
      echo -n "  [?] $1 [$prompt] "

      # Read the answer (use /dev/tty in case stdin is redirected from somewhere else)
      read reply </dev/tty

      # Default?
      if [[ -z "$reply" ]]; then
        reply=$default
      fi

      _logMessage " [?] $1 [$prompt]: $reply\n"

      # Check if the reply is valid
      case "$reply" in
      Y* | y*) return 0 ;;
      N* | n*) return 1 ;;
      esac
    done
  fi
}

# Usage _hasSudo
#
# Ensure user has root access and also that the script is not running as root
# Halts all activity if running as root
_hasSudo() {
  isRoot=$(id -u)
  if [[ ! ${CIRCLECI} && ${isRoot} = 0 ]]; then
    _errorExit "Please run scripts as a normal user and not as root"
  fi
  if ! sudo -n true 2>/dev/null; then
    # prompt for password and elevate privilege
    printf "\nPlease provide your root password to allow this script to work as intended\n"
    sudo -v
  fi
}

# Usage _installPackage <package-name>
#
# Based on the OS in use, install the specified package
_installPackage() {
  if [[ "$#" -ne 1 ]]; then
    _errorExit "Function _installPackage expected 1 (one) parameter but got $#: '$*'.  Usage: _installPackage '<package-name>'"
  fi

  _isOnline
  _hasSudo
  _outputMessage "Trying to install $1"

  case $(_getLinuxVersion) in
  arch)
    yay -S --noconfirm --needed --overwrite '*' "${1}"
    ;;
  debian)
    sudo apt install -y "${1}"
    ;;
  fedora)
    sudo dnf install -y "${1}"
    ;;
  *)
    _errorExit "Could not determine OS/distro in use to install $1. Parser found $(_getLinuxVersion)"
    ;;
  esac

  _outputMessage "Successfully installed $1"
}

# Usage _isOnline
#
# Ensure Internet connection, exits if there's no connection
_isOnline() {
  # circleci will not run ping, and will fail with a socket error
  # so if circleci, assume we have an internet connection
  if [[ ! ${CIRCLECI} ]]; then
    isOnline=$(ping -q -w1 -c1 google.com &>/dev/null && echo online || echo offline)
    if [[ ${isOnline} == "offline" ]]; then
      _errorExit "Cannot install packages when offline"
    else
      _outputMessage "Internet connection verified successfully"
    fi
  else
    _outputMessage "Skipping internet connection check"
  fi
}

# Display header message, mostly used for a nice separator between "execution phases"
#
# $1 - message
_writeHeader() {
  local h="$@"

  echo "---------------------------------------------------------------"
  echo "     ${h}"
  echo "---------------------------------------------------------------"
}