On Sat, Jan 8, 2011 at 12:04 AM, Michael Gardner <gardne...@gmail.com> wrote: > On Jan 7, 2011, at 9:19 PM, Ken Wesson wrote: > >> On the other hand, running a job scheduler from outside Clojure >> results in cranking up a big, slow to start up, expensive JVM process >> every single time a task needs to run, each of which runs one task >> once, and the scheduling itself must be done in an icky language like >> shell or cron's idiosyncratic "crontab" files with icky error >> reporting (e.g., need to run a local mail *server* to receive error >> notifications). > > If you care about startup times, you can use nailgun. But that shouldn't > matter unless you're running the job every minute or something.
Obviously, that requires knowing about, and learning how to use, nailgun. Solutions with a higher cost in novel-tools-you-have-to-figure-out-how-to-use are not, all other things being equal, superior ones. > As for scheduling, crontabs are really not hard to figure out. If you need > more complex scheduling, you can do that from your Clojure script > (essentially using cron to set the polling interval). If you're going to do that anyway, you might as well do the whole thing from inside Clojure. > And what kinds of error reporting could you do from a persistent daemon that > you couldn't also do from a cron job? Besides, most > systems that have cron also come with postfix (though it's disabled by > default on Mac OS X), so all you have to do is add your email > address to /etc/aliases. Email-based error reporting for background tasks is > really nice because you don't have to remember to check > some log file or other task-specific status indicator periodically (which has > burned me in the past). Well, both Windows and MacOS have variations on the nifty concept of "tray notification". > But this is all somewhat beside the point. What Trevor said sounded as though > the specific types of tasks he mentioned (sending > emails and checking some kind of status via web app) were particularly > unsuited to scheduled jobs; I was asking what it was about > those tasks in particular that made him lean towards a daemon instead. Maybe he needs timely responses to something, so something more akin to a web server than a periodically-run job? -- 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
