style(unitproc/):Shorten names of template prefix (bktemp -> bkt)

[BK-2020-03.git] / unitproc / bkt-timeUntilNextDay

diff --git a/unitproc/bkt-timeUntilNextDay b/unitproc/bkt-timeUntilNextDay
new file mode 100644 (file)
index 0000000..ae7562a
--- /dev/null
+++ b/unitproc/bkt-timeUntilNextDay
@@ -0,0 +1,54 @@
+#!/bin/bash
+# Desc: Template to report seconds until beginning of next day
+
+#==BEGIN Define script parameters==
+#===BEGIN Declare local script functions===
+yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
+die() { yell "$*"; exit 111; }
+try() { "$@" || die "cannot $*"; }
+timeUntilNextDay(){
+    # Desc: Report seconds until next day.
+    # Version: 1.0.3
+    # Output: stdout: integer seconds until next day
+    # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
+    # Usage: timeUntilNextDay
+    # Usage: if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement"; exit 1; fi
+    # Depends: date 8, echo 8, yell, try
+    
+    local returnState timeCurrent timeNextDay secondsUntilNextDay
+    timeCurrent="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
+    timeNextDay="$(date -d "$timeCurrent next day" --iso-8601=date)"; # Produce timestamp of beginning of tomorrow with resolution of 1 second.
+    secondsUntilNextDay="$(( $(date +%s -d "$timeNextDay") - $(date +%s -d "$timeCurrent") ))" ; # Calculate seconds until closest future midnight (res. 1 second).
+    if [[ "$secondsUntilNextDay" -gt 0 ]]; then
+       returnState="true";
+    elif [[ "$secondsUntilNextDay" -eq 0 ]]; then
+       returnState="warning_zero";
+       yell "WARNING:Reported time until next day exactly zero.";
+    elif [[ "$secondsUntilNextDay" -lt 0 ]]; then
+       returnState="warning_negative";
+       yell "WARNING:Reported time until next day is negative.";
+    fi
+
+    try echo "$secondsUntilNextDay"; # Report
+    
+    # Determine function return code
+    if [[ "$returnState" = "true" ]]; then
+       return 0;
+    elif [[ "$returnState" = "warning_zero" ]]; then
+       return 1;
+    elif [[ "$returnState" = "warning_negative" ]]; then
+       return 2;
+    fi
+} # Report seconds until next day
+#===END Declare local script functions===
+#==END Define script parameters==
+
+
+#==BEGIN sample code==
+try echo "Time until next day (seconds):$(timeUntilNextDay)" # simple report
+
+if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement for myTTL:$myTTL"; exit 1; fi # Use of exit code to exit early if time <= 0.
+#==END sample code==
+
+# Author: Steven Baltaktei Sandoval
+# License: GPLv3+