Hey, So yesterday we discussed concurrency at our meetup (http://www.meetup.com/Budapest-Clojure-User-Group/) and a question occurred to me.
Suppose we have a classic web application. (I'm not currently building such a web app in Clojure, so that's a "theoretical" question). When the user signs up, a verification email has to be sent and the database entry related to the user has to be updated (or a new datom created ;) ) to reflect the fact that we've sent out the email to the user. First, we want this to be consistent so that the "verification_sent_out" db field reflects whether the email has really been sent out or not. Secondly, we also want the email to only be sent out once. My first idea was to use a transaction but if the transaction retries, the email could be sent out several times. A fellow Clojurian advised the sending of the email to be performed by an agent. The agent is "transaction aware" so if the wrapping transaction is retried several times it only sends out the email when the transaction successfully runs. Is this how this actually works? Is there another, simpler and/or more robust solution? In the languages I come from (e.g Ruby) I'd use a library that handles the queueing and consumption of tasks. Is this how you'd do it in Clojure or it's one of these cases where Clojure itself suffices where other languages are lacking? Thank you for your answer,-- Balint -- -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
