[Feature] Continuous Deployment Hours

[davidcornu]

Closes https://github.com/Shopify/shipit-engine/issues/1100.

User-visible changes

Adds a new settings page where the continuous deployment schedule can be configured.

Stacks settings	Schedule

Code changes

• Adds a new continuous_delivery_schedules table, structured as a series of *_enabled, *_start, and *_end fields for each day of the week.
  • By default every day is enabled with a time window that covers the whole day
• Adds a new ContinuousDeliverySchedule model which wraps the logic to determine whether a deploy should be allowed
• Stack records can have one or zero associated ContinuousDeliverySchedule records (enforced via unique index)
• Adds new routes, a controller, and a view to render the UI
  • Also adds a little bit of coffeescript to power the Copy to all button
• Adds a check in ContinuousDeliveryJob to bail out if we are currently outside of a deployment window
  • From what I can tell this job runs every minute so I deemed this sufficient (one might imagine wanting to pause the job until the next deployment window but that'd likely be overkill)

Notes

• The UI is largely inspired by Google Calendar's settings for working hours
• I considered allowing the timezone to be configured per-schedule as this would be useful for cross-timezone teams.
  • Howewer
    • Doing this with ActiveRecord::Type::Time would require very localized timezone overrides (e.g. when parsing form data) which would be tricky to get right, easy to break, and may cause unintended consequences elsewhere.
    • A more robust approach (IMHO) would involve using a custom type (to basically store "HH:MM" as a string) and control all conversions to and from timestamps.
  • I'm happy to explore either of these options but I figured I would submit the most straightforward route as
    • This config is unlikely to change often
    • In most scenarios I would expect the host app to have to most appropriate timezone configured for the people using it

[davidcornu]

I have signed the CLA!

[davidcornu]

I don't believe this CI failure (https://github.com/Shopify/shipit-engine/actions/runs/10541191179/job/29206691546?pr=1361) is related to my changes but please correct me if I'm wrong.

[casperisfine]

Looks neat. I don't have any concern about the implementation. Did you try it in prod?

[davidcornu]

Did you try it in prod?

Gonna roll it out today and report back

[davidcornu]

Quick update - was on vacation for a bit so there was a bit of a delay in getting this deployed. We are running it in production as of today. Will report back with any issues we run into.

[davidcornu]

@casperisfine We've been running this branch in production for just over a week and I have nothing to report other than it's been working as advertised.

[davidcornu]

Thanks @casperisfine ❤️