helper

#!/bin/bash
# 
# A helper script to simplify the collection of a few host-specific items...
#
# ./helper -a
#   - returns the appropriate hardware architecture for use with open-horizon
# ./helper -g
#   - returns the IP address of the first default gateway for this host
# ./helper -i
#   - returns one of the IP address on the first default interface for this host
# ./helper -z
#   - returns all of the above (really just for development convenience)
#

DEBUG=0
if [ ${DEBUG} -gt 0 ]; then echo "DEBUG is on."; fi


# Return the Horizon architecture string for this platform
show_architecture () {
  if [ ${DEBUG} -gt 0 ]; then echo "Architecture."; fi
  RAW_ARCH=$(uname -m)
  if [[ "$RAW_ARCH" == "x86_64" ]]; then
    ARCH=amd64
  elif [[ "$RAW_ARCH" == "i386" ]]; then
    ARCH=amd64
  elif [[ "$RAW_ARCH" == "aarch64" ]]; then
    ARCH=arm64
  elif [[ "$RAW_ARCH" == "arm"* ]]; then
    ARCH=arm
  else
    # Other. Fail!
    ARCH=error
  fi
  echo "${ARCH}"
}

# Return the default gateway address for this host
show_gateway () {
  if [ ${DEBUG} -gt 0 ]; then echo "Gateway Address."; fi
  if [[ "$OSTYPE" == "linux-"* ]]; then
    # Linux
    GATEWAY=$(ip route | grep default | head -1 | cut -d' ' -f3)
  elif [[ "$OSTYPE" == "darwin"* ]]; then
    # MacOSX
    GATEWAY=$(netstat -nr | grep default | head -1 | awk '{print$2}')
  else
    # Other. Best guess:
    GATEWAY=$(ip route | grep default | head -1 | cut -d' ' -f3)
  fi
  echo "${GATEWAY}"
}

# Return the default interface's IP address for this host
show_ip () {
  if [ ${DEBUG} -gt 0 ]; then echo "IP Address."; fi
  if [[ "$OSTYPE" == "linux-"* ]]; then
    # Linux
    CIDR=$(ip route | grep default | head -1 | sed 's/ proto dhcp / /' | cut -d' ' -f3 | cut -d'.' -f1-3)'.0/24'
    if [ ${DEBUG} -gt 0 ]; then echo "CIDR=${CIDR}"; fi
    HOST_IP=$(ip route | grep "${CIDR}" | head -1 | sed 's/ proto [a-z]*//' | cut -d' ' -f7)
  elif [[ "$OSTYPE" == "darwin"* ]]; then
    # MacOSX
    HOST_IP=$(host `hostname` | head -1 | sed 's/.* //')
  else
    # Other. Best guess:
    CIDR=$(ip route | grep default | head -1 | sed 's/ proto dhcp / /' | cut -d' ' -f3 | cut -d'.' -f1-3)'.0/24'
    if [ ${DEBUG} -gt 0 ]; then echo "CIDR=${CIDR}"; fi
    HOST_IP=$(ip route | grep "${CIDR}" | head -1 | sed 's/ proto [a-z]*//' | cut -d' ' -f7)
  fi
  echo "${HOST_IP}"
}

while getopts ":agiz" opt; do
  case ${opt} in
    a )
      show_architecture;
      exit 0;
      ;;
    g )
      show_gateway;
      exit 0;
      ;;
    i )
      show_ip;
      exit 0;
      ;;
    z )
      echo -n "Architecture:   ";
      show_architecture;
      echo -n "Gateway:        ";
      show_gateway;
      echo -n "IP Address:     ";
      show_ip;
      exit 0;
      ;;
    \? ) echo "Usage: $0 [-a|-g|-i|-z]"
      ;;
  esac
done