Keep trying a command every X minutes, and stop after Y minutes have passed, or the command succeeds

keep-trying.sh

#!/bin/sh

#---------------------------------------------------------------------------------------------------
# Usage
#
usage() {
  printf "$(basename "$0") -s <TIME_BETWEEN_TRIES> -t <TIME_TO_TRY> <COMMAND>\n"
  printf "  where:\n"
  printf "    -s TIME_BETWEEN_TRIES  time (minutes) between each try\n"
  printf "    -t TIME_TO_TRY         total time (minutes) to try the command before giving up\n"
  printf "       COMMAND             command to try\n"
}

#---------------------------------------------------------------------------------------------------
# Check command-line args
#
# Defaults
time_between_tries=0
time_to_try=0
while getopts ':s:t:h' option; do
  case "$option" in
    s)
      time_between_tries=$OPTARG
      ;;
    t)
      time_to_try=$OPTARG
      ;;
    h)
      usage
      exit
      ;;
   \?) printf "Invalid option: -%s\n" "$OPTARG" >&2
       usage >&2
       exit 1
       ;;
  esac
done
shift $((OPTIND - 1))
if [ $time_between_tries -eq 0 ] && [ $time_to_try -eq 0 ] ; then
    usage ; exit
fi
if [[ "$#" -lt 1 ]] ; then
    usage ; exit
fi

#---------------------------------------------------------------------------------------------------
# Get command-line arguments
#
command="$@"

#---------------------------------------------------------------------------------------------------
# Define some colors for printfs
#
RED='\e[0;31m'
GREEN='\e[0;32m'
YELLOW='\e[0;33m'
BLUE='\e[0;34m'
MAGENTA='\e[0;35m'
CYAN='\e[0;36m'
WHITE='\e[0;37m'
BLACK='\e[0;38m'
BOLDYELLOW='\e[1;33m'
NOCOLOR='\e[m'

#---------------------------------------------------------------------------------------------------
# Print what's going to happen
#
printf "\n${CYAN}===>${NOCOLOR} Trying the command ${YELLOW}${command}${NOCOLOR} every ${BLUE}${time_between_tries}${NOCOLOR} minutes for ${MAGENTA}${time_to_try}${NOCOLOR} minutes...\n\n"

#---------------------------------------------------------------------------------------------------
# Try the command
#
# Try the command the first time
eval $command
# Capture the return code
return_code=$?
# Print success or failure
if [[ $return_code -eq 0 ]] ; then
    printf "\n${CYAN}===>${NOCOLOR} Command ${GREEN}SUCCEEDED${NOCOLOR} the first time\n"
    exit 0
fi
# Keep trying again if it failed
try_count=1
while (( $return_code != 0 )) && (( $SECONDS < $((time_to_try * 60)) )) ; do
    # Update try count
    try_count=$(($try_count + 1))
    # Print failure
    printf "\n${CYAN}===>${NOCOLOR} Command ${RED}FAILED${NOCOLOR}, trying again in ${time_between_tries} mins...\n\n"
    # Sleep
    sleep $((time_between_tries * 60))
    # Try command
    eval $command
    # Capture the return code
    return_code=$?
done
# Print success or failure
if [[ $return_code -eq 0 ]] ; then
    printf "\n${CYAN}===>${NOCOLOR} Command ${GREEN}SUCCEEDED${NOCOLOR} after ${try_count} tries\n"
else
    minutes_passed=$((SECONDS / 60))
    printf "\n${CYAN}===>${NOCOLOR} Command ${RED}FAILED${NOCOLOR} after ${try_count} tries (${minutes_passed} minutes)\n"
fi