get_aws_unique_id

#!/bin/bash

#
# get_aws_unique_id: prints a unique id for an AWS instance suitable for use with SignalFx.
# exits with 0 if the unique id was generated succesfully
# exits with 1 if the curl for data succeeded but the parsing of the information failed.
# exits with 28 if there was a timeout talking to AWS to get information
# all other exit codes come from curl
#
DOC="$(curl -s --connect-timeout 1 http://169.254.169.254/2014-11-05/dynamic/instance-identity/document)"
status=$?
if [ $status -eq 0 ]; then
   eval "$(echo "$DOC" | awk -F: '
   function print_var(line){
       split($1, name_parts, "\"")
       split($2, val_parts, "\"")
       printf("_%s=%s\n", toupper(name_parts[2]), val_parts[2])
   }
   $1~/ *\"accountId\"/{ print_var($0) }
   $1~/ *\"instanceId\"/{ print_var($0) }
   $1~/ *\"region\"/{ print_var($0) }
   ')"
   
   if [ ! -z "${_INSTANCEID}" -a ! -z "${_REGION}" -a ! -z "${_ACCOUNTID}" ]; then
     _AWS_UNIQUE_ID=${_INSTANCEID}_${_REGION}_${_ACCOUNTID}
     printf "%s" "${_AWS_UNIQUE_ID}" 
     exit 0
   fi
   status=1
fi
exit ${status}