Whenever VS Sidekiq

Learn about Unix cron and use the whenever gem.

there are cronjob gems available, i believe https://github.com/javan/whenever or so seems to be used frequently

- Use them on a specific schedule as needed by your application, such as taking backups, sending periodic reminders or notifications for users, cleaning the database tables, etc. You can use a gem such as Whenever for managing scheduled cron jobs.

whenever gem is used in Rails applications to schedule cron jobs e.g. send email notification about monthly expenditure on the 1st of each month.

Then you can use the whenever gem to schedule stuff.

- [whenever](https://github.com/javan/whenever)

whenever

There are multiple ways to achieve this. Probably the simplest and most reliable is to rely on cron to run your process every minute. Cron keeps track of time and executes your script each minute. This has the added benefit of avoiding a long running process (which can have its own issues). You can even have your script install it’s own cron job using the Whenever gem.

Rake tasks can be called from Cron, so we'll use the Whenever Gem to automatically add our job to our Crontab during deployment, and keep our schedule in change control.

I'd say Sidekiq is the top competitor here.

There's something wrong at Redislabs, it took them over a year to get RESP3 rolled out into their hosted service, you'd expect a rollout of that to be a bit quicker when they're the owner of Redis.

It affected us when upgrading Sidekiq to version 7, which dropped support for older Redis, and their Envoy proxy setup didn't support HELLO and RESP3: https://github.com/sidekiq/sidekiq/issues/5594

That depends on how the `maxmemory-policy` is configured, and queue systems based on Redis will tell you not to allow eviction. https://github.com/sidekiq/sidekiq/wiki/Using-Redis#memory (it even logs a warnings if it detects your Redis is misconfigured IIRC).

Sidekiq https://sidekiq.org/: This one started as an open source project, once it got enough traction, the developer made a premium version of it, and makes money by selling licenses to businesses.

Sidekiq will drop in-progress jobs when a worker crashes. Sidekiq Pro can recover those jobs but with a large delay. Sidekiq is excellent overall but it’s not suitable for processing critical jobs with a low latency guarantee.

https://github.com/sidekiq/sidekiq/wiki/Reliability

> I'm not sure feature withholding has traditionally worked out well in the developer space.

I think it's worked out well for Sidekiq (https://sidekiq.org). I really like their model of layering valuable features between the OSS / Pro / Enterprise licenses.

I was studying Sidekiq's page on rate limiters. The first type of rate limiting mentioned is the concurrent limiter: only n tasks are allowed to run at any point in time. Note that this is independent of time units (e.g. per second), or how long they take to run. The only limitation is the number of concurrent tasks/requests.

The code above isn't idempotent. If you run it twice, it will create two copies, which is probably not what you intended. Why is this important? Because most backend job processors like Sidekiq don't make any guarantees that your jobs will run exactly once.