On Friday, August 30, 2013 11:16:21 AM UTC-6, Peter Skirko wrote: > Hi, > > I am trying to understand when it is safe to catch errors in node.js code, > by which I mean both node.js core and userland code as well. > > According to http://nodejs.org/api/domain.html, > > "By the very nature of how throw works in JavaScript, there is almost > never any way to safely "pick up where you left off", without leaking > references, or creating some other sort of undefined brittle state. The > safest way to respond to a thrown error is to shut down the process." > > Thus a naive rule is "Don't catch errors in your code. If you see an > error, shut down the process after some mild cleanup (restart via cluster > or equivalent process watcher). And don't use other code that catches > exceptions either, by the same reasoning." > > However, grepping in the node.js core, I find that it uses catch in quite > a few situations. Here's just one example, from lib/fs.js: > > fs.existsSync = function(path) { > try { > nullCheck(path); > binding.stat(pathModule._makeLong(path)); > return true; > } catch (e) { > return false; > } > }; > > As someone who is not steeped deeply in node.js on a daily basis, I have > no way of understanding how the core can catch errors (> 30 locations with > a simple grep) without leaking references or creating brittle state. > Naively, if it followed the "domain rule", it should be exception neutral > and propagate all exceptions upward so that the process can fail. > > Is there some way, like a rule of thumb or such, whereby I can determine > that the core is in fact safe? It's just not clear to a casual observer, > but seems deeply important for building robust node processes. I also don't > want to just say to myself "it's in the core therefore it must be safe", > b/c if that's not true, then I put production code at risk for unexpected > issues. > > Any help would be appreciated, thanks in advance! > > -Peter >
There is some discussion in this post: https://groups.google.com/d/topic/nodejs/4TYtu_xnNJY/discussion -- -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. To post to this group, send email to nodejs@googlegroups.com To unsubscribe from this group, send email to nodejs+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nodejs?hl=en?hl=en --- You received this message because you are subscribed to the Google Groups "nodejs" group. To unsubscribe from this group and stop receiving emails from it, send an email to nodejs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
