solid_queue doesn't raise a warning when fugit should generate multiple CRONs

[kghandour]

SolidQueue uses fugit to parse recurring tasks schedules. If you enter a schedule in natural language that generates multiple CRONs, only the first CRON is considered, and the other CRONs are ignored without warning. It might be a good idea to raise an error or a warning when that happens.

Normal case

For normal cases, with schedule

schedule: every day at 00:40

The corresponding fugit translation would result in this object.

> require 'fugit'; Fugit.parse('every day at 00:40')


#<Fugit::Cron:0x00007f5e11978d50
 @cron_s=nil,
 @day_and=nil,
 @hours=[0],
 @minutes=[40],
 @monthdays=nil,
 @months=nil,
 @original="40 0 * * *",
 @seconds=[0],
 @timezone=nil,
 @weekdays=nil,
 @zone=nil>

For schedules that only generate a single CRON like this:

schedule: every day at 00:40 and 15:40

The corresponding fugit translation results in this object:

#<Fugit::Cron:0x00007f5e116858c8
 @cron_s=nil,
 @day_and=nil,
 @hours=[0, 15],
 @minutes=[40],
 @monthdays=nil,
 @months=nil,
 @original="40 0,15 * * *",
 @seconds=[0],
 @timezone=nil,
 @weekdays=nil,
 @zone=nil>

Breaking case

However, for schedules that cannot be converted via fugit to a single CRON, like this

schedule: every day at 00:40 and 15:20

The corresponding fugit trims off the second schedule entirely and only results in:

#<Fugit::Cron:0x00007f5e117d43a0
 @cron_s=nil,
 @day_and=nil,
 @hours=[0],
 @minutes=[40],
 @monthdays=nil,
 @months=nil,
 @original="40 0 * * *",
 @seconds=[0],
 @timezone=nil,
 @weekdays=nil,
 @zone=nil>

This results in solid_queue only running the recurring task at one time and not reporting a failure.

Possible solution

A possible solution would be to use Fugit::Nat to parse and have multi: fail set to true.

schedule: every day at 00:40 and 15:20

Fugit::Nat.parse('every day at 00:40 and 15:20', multi: :fail)
(app):7:in '<top (required)>': multiple crons in "every day at 00:40 and 15:20" - {monthday: (slot :monthday "*" {weak: true})} (ArgumentError)

Or, for a safer approach if solid_queue can support multi CRONs,

Fugit::Nat.parse('every day at 00:40 and 15:20', multi: true)
 =>
[#<Fugit::Cron:0x00007f5e116ab0f0
  @cron_s=nil,
  @day_and=nil,
  @hours=[0],
  @minutes=[40],
  @monthdays=nil,
  @months=nil,
  @original="40 0 * * *",
  @seconds=[0],
  @timezone=nil,
  @weekdays=nil,
  @zone=nil>,
 #<Fugit::Cron:0x00007f5e116aae70
  @cron_s=nil,
  @day_and=nil,
  @hours=[15],
  @minutes=[20],
  @monthdays=nil,
  @months=nil,
  @original="20 15 * * *",
  @seconds=[0],
  @timezone=nil,
  @weekdays=nil,
  @zone=nil>]

Hope the description helps. Thought it would be a good idea to report this in case someone else goes through something similar and cannot debug why the recurring task is not running as expected.