CRON Expression Parser

================================

This utility parses the cron expression to scheduled time.

This utility can be used from command line.

System Requirements:

• A machine with python 3.10+ installed

To install Dev Dependencies

• No dependency

To install Test Dependencies

pip install -r test-requirements.in

To run the parser

python parser_client.py "<Input>"

To Run the test cases

pytest --verbose --failed-first

Input to the script: A cron expression with following time fields: MINUTE, HOUR, DAY-OF-MONTH, MONTH, DAY-OF-WEEK, COMMAND.

The order of expression should be same as time fields are mentioned, first MINUTE and last is COMMAND.

Constraints/Usage:

1. Every numeric value should be in the supported range.

   • MINUTE: 0 to 59
   • HOUR: 0 to 23
   • DAY OF MONTH: 1 to 31
   • MONTH: 1 to 12
   • DAY OF WEEK: 1 to 7

2. Except COMMAND, all other field supports Range (-):

   • It indicates all the values in given range.
   • No special char allowed.
   • Example: 0-5 * * * * /user This means minutes will have values 0, 1, 2, 3, 4, 5

3. Except COMMAND, all other field supports seperator (/):

   • left side of separator can have a number or *
   • right side should be a number

4. Except COMMAND, all other field supports ALL (*):

   • Example: * * * * * /user This means every minute, every hour, every day of month etc.

5. Except COMMAND, all other field supports specific (,):

   • It means consider only specified values
   • No special char allowed.
   • Example: 1,5 * * * * /user This means minutes will have values 1, 5

Output from the script:

python parser_client.py "0 0 12 6 5 /user"

{
  'MIN': [0],
  'HOUR': [0],
  'DAY-OF-MONTH': [12],
  'MONTH': [6],
  'DAY-OF-WEEK': [5],
  'COMMAND': "/user"
}