@Isaacs Thanks for the module! It has a nice clean syntax. I may replace actionHero's cluster server with it :D
I too agree that having a 'graceful reload' feature in clustered deployments is a great feature. This is especially useful when you host the app yourself and don't rely on providers like appfog and heroku where "deployments" are literally new "servers" switched at the load balancer. However, I am in agreement with Isaacs that building a "graceful reload" into node's core cluster module is a bad idea. I think that doing so would create a very complex API which is also very likely not to cover everyone's use cases. Some examples: If your app is just an http(s) server, all you need to do is call `server.close()`. Node is awesome and the server will stop handling new connections, and will still finish existing requests. However, how do you know to wait until all requests are complete before terminating this child? How long do you wait? What if there are websockets bound to this server? Will your clients know how to reconnect? What if you have a socket/tls server? You probably need to signal each client with a 'goodbye' message and be sure that whatever they are working on is complete. Perhaps most importantly, what if your server is processing some background tasks? You need to be sure that they are allowed to finish, less you loose the job they are working on. Here are links to my examples above. These are all "teardown" functions which every worker in the custer does when it is signaled to shut down (and they are all from one application!). Web (http/https) server: https://github.com/evantahler/actionHero/blob/master/servers/web.js#L66-L69 Telnet/TLS socket server: https://github.com/evantahler/actionHero/blob/master/servers/socket.js#L214-L239 Background Task Worker: https://github.com/evantahler/actionHero/blob/master/initializers/taskProcessor.js#L27-L43 On Friday, June 7, 2013 6:26:57 PM UTC-7, ryandesign wrote: > > > On Jun 7, 2013, at 19:10, Isaac Schlueter wrote: > > > I do this with the npmjs.org site using the cluster-master module. > > > > https://npmjs.org/package/cluster-master > > Thanks, I'm sure I've heard of that before, and will remember to look into > it once I get to the point of deploying. > > > > I only have to restart the main process if there's a change to the > > main server.js file. Otherwise, I log into the repl, and I can > > restart workers one by one, resize the cluster, etc. > > I guess I don't understand how this is accomplished. What repl are you > talking about? Is this something custom you've written for the npmjs web > site or is this easily available to anyone's nodejs site using the standard > repl that appears when you run "node"? Could you point me to an example? > > > > Getting all the edge cases handled properly is very app-specific, and > > in multi-machine setups, it will be completely extraneous. > > > > So, unlike Ben, I would reject a pull request flat-out for this > > feature, unless someone could present a *very* compelling case for why > > everyone ought to have the same logic in all their apps. I don't > > believe that this belongs in core. > > Regardless of whether you run a single node process on a single server or > several processes on several servers, most everyone will eventually want to > deploy an updated version of the code and restart the server, and I don't > think it's controversial to claim that doing so gracefully, without losing > any connections, is best. Why, then, should each developer need to figure > out anew how to do that, especially when as you say it's difficult to get > right? > > > -- -- 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 [email protected] To unsubscribe from this group, send email to [email protected] 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 [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
