On Thu, Sep 25, 2014 at 12:51 PM, George Neuner <gneun...@comcast.net> wrote: > Hi Jay, > > On 9/23/2014 10:03 PM, Jay McCarthy wrote: > > The command-line tool is basically deprecated and only provided for > backwards compatibility. There is a huge amount that it can't do at > all and it hasn't been the primary way that we recommend using the Web > server for a very long time. > > > I'm not using the plt-web-server app - I created a minimal application that > set up the environment: directories, ports, etc. and a start function that > just returns a 404 if called. My server sits behind Apache and only handles > servlets, which I would like to be demand load modules so they can be added > to and updated easily. That's why I am interested in being able to unload > servlets on command, though not necessarily all of them at once (although > that also is helpful). > > >> Not really knowing much about Racket's internals he naively asks: >> Could a server pre-load the commonly used webserver modules and make >> them available to new module servlets, or does the custodian >> implementation make doing that difficult/impossible? > > This is the purpose of the make-servlet-namespace argument of > configuration-table->web-config@ but there is no option in the > configuration file for that argument. > > http://docs.racket-lang.org/web-server-internal/Web_Servers.html?q=servlet-namespace#%28def._web-config._%28%28lib._web-server%2Fweb-config-unit..rkt%29._configuration-table-~3eweb-config~40%29%29 > > > The namespace facility seems designed more for user written modules than for > library modules. > > My analysis may be off-base as I have very little experience working > directly with custodians, but it seems that when a dynamic servlet is first > loaded, its custodian spends a lot of additional time (re)loading library > modules that already exist in other custodians. [ Though I can't tell > exactly what's happening, I can see a lot of disk activity when I think I'm > loading a 5KB servlet. ] Reasonably I would have expected that after > loading/linking the first servlet, the libraries common to the servlets > would be already in memory. But loading additional servlets is no quicker [ > and causes a similar disk hit ] so clearly I don't understand what is > happening internally with the custodians. > > If a Racket library is deliberately put into the servlet-namespace, does > that streamline linking? >
Your assumption about the purpose of this is not correct. Anything in the servlet-namespace will be shared between all servlets, and thus not loaded per-servlet. >> My application so far is based on stateful servlets and AJAX ... stateful >> mainly because it's easier for me to understand. Currently there is >> little use of continuations, but some planned functionality will use them >> extensively and it certainly would help if debugging didn't always mean >> starting over setting up conditions in the application. > > This comment/question is related to questions 4 and 5 from the FAQ: > > http://docs.racket-lang.org/web-server/faq.html?q=servlet-namespace#%28part._update-servlets%29 > > > That link leads to a "troubleshooting" page 8-). I didn't consider the > issue to be a "problem" per se - I already knew that restarting a stateful > servlet would lose saved state. Most of my existing servlets are one-shots > that don't save any state, but they are written using the stateful language. > Only a few use continuations and not extensively (so far). I was just > thinking ahead to stuff that will need to use continuations more > extensively. > > Thanks for putting up with my questions. > George > -- Jay McCarthy http://jeapostrophe.github.io "Wherefore, be not weary in well-doing, for ye are laying the foundation of a great work. And out of small things proceedeth that which is great." - D&C 64:33 ____________________ Racket Users list: http://lists.racket-lang.org/users
