Scheduled plugin update

[rossmacarthur]

At the moment you can update all plugins using the following

sheldon lock --update

But there is no way to make sheldon run that periodically. It would be nice to make sheldon run that daily, weekly, fortnightly or a completely arbitrary period.

From https://github.com/rossmacarthur/sheldon/issues/61#issuecomment-617645339

Proposed solution

I think we could have the following in the config file

[update]
every = "2 weeks"

or

[update]
every = "1 month"

We would then store the last updated time somewhere, and if the current time is greater than the last updated time plus the every value then we try update, regardless of the command executed (lock or source).

We could accept hours, days, weeks, months, and years.

Unresolved questions

• Should multiple units be allowed i.e. "2 weeks 1 day"

• Where should the last updated time be stored?

  If we store in the plugins.lock file then we have to keep track of it every time we relock the file we have to read it and rewrite it. It might be easier to store it in a different file in the data directory. Perhaps some sort of state file.

[tapeinosyne]

I feel that a built-in scheduled update mechanism would be dispensable, given how strongly established is the practice of delegating such tasks to specialized tools such as cron. Moreover, there are not many CLI utilities — none come to mind, to be entirely honest! — that will spontaneously perform an update when given unrelated commands.

Perhaps it would be best to keep things lean, here?

[rossmacarthur]

I agree, that sounds reasonable, I'm okay with not implementing this.