retry module integration

[softprops]

would like to retry if a send fails. this should use retry to retry futures

[daddykotex]

Let's reopen if someone ask for that.

[colindean]

Consider this an ask for retry! I'd love to rip out the direct JavaMail implementation in https://github.com/target/data-validator and use something more idiomatic.

[daddykotex]

Will look into it soon.

What would be an ideal interface for you to implement this, can you share some code?

[colindean]

Thanks for considering this!

In this comment, I explored a pair of retry solutions that met my expectations for interface and code quality (I've implemented internal retry libraries in three languages at three companies in the last decade, so I've got strong opinions loosely held, haha). Either will do just fine, I think.

The builder pattern in courier.Session lends itself well to adding a retry configuration case class. The courier.Mailer#apply method would consume that configuration here:

courier/src/main/scala/mailer.scala

Lines 36 to 38 in 9533af2

	Future {
	Transport.send(msg)
	}

Since courier is already using Futures there, it's probably cleanest to use SoftwareMill's retry package. The above would be come something like this:

val retry = buildRetryPolicyFromConfig(_session.retryConfig)
retry(() => Future {
      Transport.send(msg)
})

[daddykotex]

One month later, sorry, life happens ehh.

I'm checking it out today.

The plan would be to put that feature in a separate artifact: courier-retry to let user import it if they want to.

[daddykotex]

WIP: #61

I need retry for scala 3: softwaremill/retry#39

I would like some feedback from you @colindean. See the readme update in the PR and let me know what you think.

More specifically, what do you think of:

• exposing the retry.Policy directly in the RetryConfig class. this provide users (you) the most control over the behavior at the expense of simplicity (for example, only taking a maximum number of attempt and using a simple retry.Pause(numberOfAttempts, 10.seconds) under the hood)
• the extension method on the Mailer (via the Retry._ import)