Full Regex for ScheduleExpression property of AWS CloudWatch Events Rule

aws-cloudwatch-events-rule-scheduleexpression.js

"^(rate\\(((1 (hour|minute|day))|(\\d+ (hours|minutes|days)))\\))|(cron\\(\\s*($|#|\\w+\\s*=|(\\?|\\*|(?:[0-5]?\\d)(?:(?:-|\/|\\,)(?:[0-5]?\\d))?(?:,(?:[0-5]?\\d)(?:(?:-|\/|\\,)(?:[0-5]?\\d))?)*)\\s+(\\?|\\*|(?:[0-5]?\\d)(?:(?:-|\/|\\,)(?:[0-5]?\\d))?(?:,(?:[0-5]?\\d)(?:(?:-|\/|\\,)(?:[0-5]?\\d))?)*)\\s+(\\?|\\*|(?:[01]?\\d|2[0-3])(?:(?:-|\/|\\,)(?:[01]?\\d|2[0-3]))?(?:,(?:[01]?\\d|2[0-3])(?:(?:-|\/|\\,)(?:[01]?\\d|2[0-3]))?)*)\\s+(\\?|\\*|(?:0?[1-9]|[12]\\d|3[01])(?:(?:-|\/|\\,)(?:0?[1-9]|[12]\\d|3[01]))?(?:,(?:0?[1-9]|[12]\\d|3[01])(?:(?:-|\/|\\,)(?:0?[1-9]|[12]\\d|3[01]))?)*)\\s+(\\?|\\*|(?:[1-9]|1[012])(?:(?:-|\/|\\,)(?:[1-9]|1[012]))?(?:L|W)?(?:,(?:[1-9]|1[012])(?:(?:-|\/|\\,)(?:[1-9]|1[012]))?(?:L|W)?)*|\\?|\\*|(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?(?:,(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?)*)\\s+(\\?|\\*|(?:[0-6])(?:(?:-|\/|\\,|#)(?:[0-6]))?(?:L)?(?:,(?:[0-6])(?:(?:-|\/|\\,|#)(?:[0-6]))?(?:L)?)*|\\?|\\*|(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?(?:,(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?)*)(|\\s)+(\\?|\\*|(?:|\\d{4})(?:(?:-|\/|\\,)(?:|\\d{4}))?(?:,(?:|\\d{4})(?:(?:-|\/|\\,)(?:|\\d{4}))?)*))\\))$"

Doesn't match this: "0 18 ? * MON-FRI *", according to doc https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/ScheduledEvents.html#CronExpressions. Tester in https://regex101.com/r/qIWy9U/1.

Fails
cron(0 8 ? * 3#4 *)

This update covers the above use case:
^(rate\\(((1 (hour|minute|day))|(\\d+ (hours|minutes|days)))\\))|(cron\\(\\s*($|#|\\w+\\s*=|(\\?|\\*|(?:[0-5]?\\d)(?:(?:-|\\/|\\,)(?:[0-5]?\\d))?(?:,(?:[0-5]?\\d)(?:(?:-|\\/|\\,)(?:[0-5]?\\d))?)*)\\s+(\\?|\\*|(?:[0-5]?\\d)(?:(?:-|\\/|\\,)(?:[0-5]?\\d))?(?:,(?:[0-5]?\\d)(?:(?:-|\\/|\\,)(?:[0-5]?\\d))?)*)\\s+(\\?|\\*|(?:[01]?\\d|2[0-3])(?:(?:-|\\/|\\,)(?:[01]?\\d|2[0-3]))?(?:,(?:[01]?\\d|2[0-3])(?:(?:-|\\/|\\,)(?:[01]?\\d|2[0-3]))?)*)\\s+(\\?|\\*|(?:0?[1-9]|[12]\\d|3[01])(?:(?:-|\\/|\\,)(?:0?[1-9]|[12]\\d|3[01]))?(?:,(?:0?[1-9]|[12]\\d|3[01])(?:(?:-|\\/|\\,)(?:0?[1-9]|[12]\\d|3[01]))?)*)\\s+(\\?|\\*|(?:[1-9]|1[012])(?:(?:-|\\/|\\,)(?:[1-9]|1[012]))?(?:L|W|#)?(?:[1-9]|1[012])?(?:,(?:[1-9]|1[012])(?:(?:-|\\/|\\,)(?:[1-9]|1[012]))?(?:L|W|#)?(?:[1-9]|1[012])?)*|\\?|\\*|(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?(?:,(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?)*)\\s+(\\?|\\*|(?:[0-6])(?:(?:-|\\/|\\,|#)(?:[0-6]))?(?:L)?(?:,(?:[0-6])(?:(?:-|\\/|\\,|#)(?:[0-6]))?(?:L)?)*|\\?|\\*|(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?(?:,(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?)*)(|\\s)+(\\?|\\*|(?:|\\d{4})(?:(?:-|\\/|\\,)(?:|\\d{4}))?(?:,(?:|\\d{4})(?:(?:-|\\/|\\,)(?:|\\d{4}))?)*))\\))$

Updated version. The regex posted previously have some issue on some of the cron expression.

^rate\((?:1\s(?:hour|minute|day)|(?:[2-9]|[1-9][0-9]+)\s(?:hours|minutes|days))\)|cron\(\s*(?:\*|(?<minutes>0|[1-5]{0,1}[0-9]?)(?:(?:,(?P>minutes))*|(?:-(?P>minutes)){0,1}(?:\/[[:digit:]]){0,1}))\s\s*(?:\*|(?<hours>0|[1]{0,1}[0-9]?|2[0-3])(?:(?:,(?P>hours))*|(?:-(?P>hours)){0,1}(?:\/[[:digit:]]){0,1}))\s\s*(?:(?<qDays>\?)|\*(?<days>[1-2]{0,1}[1-9]?|31|10|20|30)(?:(?:,(?P>days))*|(?:-(?P>days)){0,1}(?:\/[[:digit:]]){0,1}|L|W))\s\s*(?:\*|(?<month>[1-9]|1[0-2])(?:(?:,(?P>month))*|(?:-(?P>month)){0,1}(?:\/[[:digit:]]){0,1})|(?<alphamonth>JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:,(?P>alphamonth))*|(?:-(?P>alphamonth)){0,1}(?:\/[[:digit:]]){0,1}))\s\s*(?(<qDays>)(?:\*|(?<week>[1-7])(?:(?:,(?P>week))*|(?:-(?P>week)){0,1}(?:\/[[:digit:]]){0,1}|L|#[1-5])|(?<alphaweek>MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:,(?P>alphaweek))*|(?:-(?P>alphaweek)){0,1}(?:\/[[:digit:]]){0,1}))|\?)\s\s*(?:\*|(?<year>19[7-9][0-9]|2[0-1][0-9][0-9])(?:(?:,(?P>year))*|(?:-(?P>year)){0,1}(?:\/[[:digit:]]){0,1}))\s*\)$

https://regex101.com/r/Fmm1VJ/1

Updated version for JS regex:

• Fix the MON-FRI not matching
• Change the 0-6 day of week to 1-7
• Fix # wildcard in day of week (e.g. "3#1,6#2" should not match)
• You can't specify the Day-of-month and Day-of-week fields in the same cron expression. If you specify a value (or a *) in one of the fields, you must use a ? (question mark) in the other.

^rate((?:1\s(?:hour|minute|day)|(?:[2-9]|[1-9][0-9]+)\s(?:hours|minutes|days)))|(?:cron(($|#|\w+\s*=|(?|*|(?:[0-5]?\d)(?:(?:-|/|,)(?:[0-5]?\d))?(?:,(?:[0-5]?\d)(?:(?:-|/|,)(?:[0-5]?\d))?)))\s+(?|*|(?:[01]?\d|2[0-3])(?:(?:-|/|,)(?:[01]?\d|2[0-3]))?(?:,(?:[01]?\d|2[0-3])(?:(?:-|/|,)(?:[01]?\d|2[0-3]))?))\s+(?|*|(?:0?[1-9]|[12]\d|3[01])(?:(?:-|/|,)(?:0?[1-9]|[12]\d|3[01]))?(?:,(?:0?[1-9]|[12]\d|3[01])(?:(?:-|/|,)(?:0?[1-9]|[12]\d|3[01]))?))(\s+)(?|*|(?:[1-9]|1[012])(?:(?:-|/|,)(?:[1-9]|1[012]))?(?:L|W)?(?:,(?:[1-9]|1[012])(?:(?:-|/|,)(?:[1-9]|1[012]))?(?:L|W)?)\s+|?|*|(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?(?:,(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC)(?:(?:-)(?:JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV|DEC))?))(\s+)((?:(?<!(?:?\5\6\7))?)|((?<=(?:?\5\6\7))(*|(?:[1-7])(?:(?:-|/|,|#)(?:[1-7]))?(?:L)?(?:,(?:[1-7])(?:(?:-|/|,)(?:[1-7]))?(?:L)?)|?|*|(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?(?:,(?:MON|TUE|WED|THU|FRI|SAT|SUN)(?:(?:-)(?:MON|TUE|WED|THU|FRI|SAT|SUN))?))))(\s\s)(?:*|(19[7-9][0-9]|2[0-1][0-9][0-9])(?:(?:,(19[7-9][0-9]|2[0-1][0-9][0-9]))|(?:-(19[7-9][0-9]|2[0-1][0-9][0-9])){0,1}(?:/[[:digit:]]){0,1}))\s)$)

For me only the first regex works in javascript, the rest all fail to compile

By no means a guaranteed fix, but I have created a repo for this express purpose that will (hopefully) be easier to understand and maintain going forward. Hope it helps 🤞