unitproc/bkt-timeUntilNextHour

   1 #!/bin/bash
   2 # Desc: Template to report seconds until beginning of next hour
   3
   4 #==BEGIN Define script parameters==
   5 #===BEGIN Declare local script functions===
   6 yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
   7 die() { yell "$*"; exit 111; }
   8 try() { "$@" || die "cannot $*"; }
   9 timeUntilNextHour(){
  10     # Desc: Report seconds until next hour
  11     # Version 1.0.1
  12     # Output: stdout: integer seconds until next hour
  13     # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
  14     # Usage: timeUntilNextHour
  15     # Usage: if ! myTTL="$(timeUntilNextHour)"; then yell "ERROR in if statement"; exit 1; fi
  16
  17     local returnState timeCurrent timeNextHour secondsUntilNextHour
  18     timeCurrent="$(date --iso-8601=seconds)"; # Produce `date`-parsable current timestamp with resolution of 1 second.
  19     timeNextHour="$(date -d "$timeCurrent next hour" --iso-8601=hours)"; # Produce `date`-parsable current time stamp with resolution of 1 second.
  20     secondsUntilNextHour="$(( $(date +%s -d "$timeNextHour") - $(date +%s -d "$timeCurrent") ))"; # Calculate seconds until next hour (res. 1 second).
  21     if [[ "$secondsUntilNextHour" -gt 0 ]]; then
  22         returnState="true";
  23     elif [[ "$secondsUntilNextHour" -eq 0 ]]; then
  24         returnState="warning_zero";
  25         yell "WARNING:Reported time until next hour exactly zero.";
  26     elif [[ "$secondsUntilNextHour" -lt 0 ]]; then
  27         returnState="warning_negative";
  28         yell "WARNING:Reported time until next hour is negative.";
  29     fi;
  30
  31     try echo "$secondsUntilNextHour"; # Report
  32
  33     # Determine function return code
  34     if [[ "$returnState" = "true" ]]; then
  35         return 0;
  36     elif [[ "$returnState" = "warning_zero" ]]; then
  37         return 1;
  38     elif [[ "$returnState" = "warning_negative" ]]; then
  39         return 2;
  40     fi;
  41 } # Report seconds until next hour
  42 #===END Declare local script functions===
  43 #==END Define script parameters==
  44
  45
  46 #==BEGIN sample code==
  47 try echo "Time until next hour (seconds):$(timeUntilNextHour)" # simple report
  48
  49 if ! myTTL="$(timeUntilNextHour)"; then yell "ERROR in if statement for myTTL:$myTTL"; exit 1; fi # Use of exit code to exit early if time <= 0.
  50 #==END sample code==
  51
  52 # Author: Steven Baltaktei Sandoval
  53 # License: GPLv3+