Re: Advice for building backend REST services from scratch using clojure
With Lispy languages, you can do whatever you want without worrying too
much about underlying web server, db, etc.
I use my own constructors like:
(define-crud-handler :employee [:path [customers cust-id sites site-id
employees] :auth-required? true]
{:collection {:create (employees-create cust-id site-id)
:read (employees-collection-read cust-id site-id
:req-params
[number draw] [number start] [number length]
order search)
:partial-update (update-employees-collection-pref [number cust-id] [number
site-id]
:req-params [keyword payment-schedule] next-pay-date)
:delete employees-collection-delete
}
:element {:read (employees-element-read cust-id site-id employee-id)
:update (employees-element-modify cust-id site-id employee-id)
:delete employees-element-delete
}})
...
(define-crud-fn employees-element-modify [cust-id site-id employee-id]
(dl/update-item :employee
{:site-id site-id :id employee-id}
(into {} (map (fn [[k v]] [k [:put v]])
(get-json-parameters)))
:return :updated-new))
In this way, I can maintain proper abstraction layers and free to change
underlying web server or db.
On Friday, 11 April 2014 00:13:19 UTC+10, Kashyap CK wrote:
Hi,
I have the opportunity to build a set of services from scratch. I plan to
use clojure for this.
I'd like to experiment with options available out there - options such as
- what webserver, what database etc. I'd like it very much if you could
share some of your experiences in this and possibly some pitfalls to avoid.
Regards,
Kashyap
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Re: Advice for building backend REST services from scratch using clojure
With Lispy languages, you can do whatever you want without worrying too
much about underlying web server, db, etc.
I use my own constructors like:
(define-crud-handler :employee [:path [customers cust-id sites site-id
employees] :auth-required? true]
{:collection {:create (employees-create cust-id site-id)
:read (employees-collection-read cust-id site-id
:req-params
[number draw] [number start] [number length]
order search)
:partial-update (update-employees-collection-pref [number cust-id] [number
site-id]
:req-params [keyword payment-schedule] next-pay-date)
:delete (employees-collection-delete cust-id site-id)
}
:element {:read (employees-element-read cust-id site-id employee-id)
:update (employees-element-modify cust-id site-id employee-id)
:delete (employees-element-delete cust-id site-id employee-id)
}})
...
(define-crud-fn employees-element-modify [cust-id site-id employee-id]
(dl/update-item :employee
{:site-id site-id :id employee-id}
(into {} (map (fn [[k v]] [k [:put v]])
(get-json-parameters)))
:return :updated-new))
In this way, I can maintain proper abstraction layers and free to change
underlying web server or db.
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Re: [ANN] Silk, an isomorphic routing library for Clojure and ClojureScript
Has anyone here had a chance to use Silk for a project they'd be willing to share? I'm a front-end web-dev newbie who has been researching server-side Om/React rendering, and it seems like Silk is ideal for this use case. However I'd be much more comfortable starting out if there were some examples to go by. On Tuesday, August 5, 2014 10:04:07 AM UTC+7, Dom Kiva-Meyer wrote: I have recently been experimenting with isomorphic Clojure and ClojureScript architecture. The goal is to make Clojure[Script] web applications that can share logic for routing, rendering, and other functionality in order to be able run in both server-side and browser-side environments. I couldn't find a suitable routing library that worked in both Clojure and ClojureScript nor could I find a routing library with a design that was suitable for porting to the other platform, so I wrote one. https://github.com/DomKM/silk The core functionality of Silk is entirely compatible with both Clojure and ClojureScript. Silk is easily extensible, which is especially important for an isomorphic library. For example, you may have routes that, on the server, should only match GET requests, but which should also work in the browser where you are not routing from an HTTP request. This functionality is trivial to add to Silk (and, as a convenience, is built in). In Silk, route matching and handling are decoupled. While this is an important architecture concern anywhere, it is an essential feature for isomorphism. Matching URLs on the server and browser will be very similar, but what you do after will likely be entirely different. You can think of routing in Silk as bidirectional (yes, routes are named) pure functions that match URLs to extract parameters or take parameters to form URLs. If this sounds like it could be useful for you, please give it a try and let me know what you think. Thanks! -- 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/d/optout.
com.stuartsierra/component ring/compojure example
Hello, I'm trying to create a web app. I'm having the damnest time trying to figure out how to layer my application. I want to pass protocol implementations to the routes. The protocols define interacting with various data sources that I need down the way. I saw Stuart Sierra's talk about Component. It looks to satisfy my needs. What I can't find is an example project for component and compojure. Unfortunately the project com.stuartsierra/component is poorly named. Googling for component + compojure brings back mostly false positives. Does anyone have a gist or blog post about how to do this? Thanks, JPD -- 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/d/optout.
Re: com.stuartsierra/component ring/compojure example
Here is a toy app that downloads nzbs from usenet: https://github.com/gar3thjon3s/leacher It's not documented, but it works. The component stuff is hooked up here: https://github.com/gar3thjon3s/leacher/blob/master/src/clj/leacher/main.clj#L53 On 7 October 2014 12:33, JPatrick Davenport virmu...@gmail.com wrote: Hello, I'm trying to create a web app. I'm having the damnest time trying to figure out how to layer my application. I want to pass protocol implementations to the routes. The protocols define interacting with various data sources that I need down the way. I saw Stuart Sierra's talk about Component. It looks to satisfy my needs. What I can't find is an example project for component and compojure. Unfortunately the project com.stuartsierra/component is poorly named. Googling for component + compojure brings back mostly false positives. Does anyone have a gist or blog post about how to do this? Thanks, JPD -- 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/d/optout. -- 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/d/optout.
Re: com.stuartsierra/component ring/compojure example
You may want to look here for integrating components in your app. https://github.com/danielsz/system/ On Tuesday, October 7, 2014 2:33:33 PM UTC+3, JPatrick Davenport wrote: Hello, I'm trying to create a web app. I'm having the damnest time trying to figure out how to layer my application. I want to pass protocol implementations to the routes. The protocols define interacting with various data sources that I need down the way. I saw Stuart Sierra's talk about Component. It looks to satisfy my needs. What I can't find is an example project for component and compojure. Unfortunately the project com.stuartsierra/component is poorly named. Googling for component + compojure brings back mostly false positives. Does anyone have a gist or blog post about how to do this? Thanks, JPD -- 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/d/optout.
Re: Advice for building backend REST services from scratch using clojure
On 11/04/2014 09:17, Colin Yates wrote: * you can fight it as hard as you like but you will eventually end up using emacs, clojure-mode, cider, paredit and magit and then wonder how you ever lived without it, but not without spending at least a month or two cursing anything to do with emacs :). Whilst I love Emacs, clojure-mode cider for working with Clojure I wasted far too much time trying to get a Clojurescript browser repl working with cider. Tried Weasel but it didn't seem to be keeping up with Clojurescript releases or else it was some other mysterious bug. Austin seemed to require far too much boilerplate addition to get anything working so I eventually resorted to Lighttable which has smooth interaction with a browser repl in Chrome. Until the whole lein/cider/Clojurescript/browser repl toolchain settles into something stable I would caution anyone trumpeting the advantages of Emacs. For Clojurescript the current state of play seems to favour Lighttable and Cursive. gvim -- 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/d/optout.
Re: Advice for building backend REST services from scratch using clojure
On 11/04/2014 09:17, Colin Yates wrote: * you can fight it as hard as you like but you will eventually end up using emacs, clojure-mode, cider, paredit and magit and then wonder how you ever lived without it, but not without spending at least a month or two cursing anything to do with emacs :). To supplement my last post, I would add that the main factor against Lighttable, for me, is its insane memory consumption. I don't know whether or not it was due to leaving it on overnight but I found it consuming 1.4GB RAM when I returned to editing the other day. To some accustomed to working with Java/JVM languages this may not be such a big deal but to me it matters as I work on my laptop much of the time. gvim -- 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/d/optout.
Re: Advice for building backend REST services from scratch using clojure
To be fair, Cursive doesn't yet provide a great CLJS REPL solution either, although that is coming soon. Right now, for ease of getting a CLJS REPL up and running Light Table definitely wins. On 8 October 2014 05:20, gvim gvi...@gmail.com wrote: On 11/04/2014 09:17, Colin Yates wrote: * you can fight it as hard as you like but you will eventually end up using emacs, clojure-mode, cider, paredit and magit and then wonder how you ever lived without it, but not without spending at least a month or two cursing anything to do with emacs :). Whilst I love Emacs, clojure-mode cider for working with Clojure I wasted far too much time trying to get a Clojurescript browser repl working with cider. Tried Weasel but it didn't seem to be keeping up with Clojurescript releases or else it was some other mysterious bug. Austin seemed to require far too much boilerplate addition to get anything working so I eventually resorted to Lighttable which has smooth interaction with a browser repl in Chrome. Until the whole lein/cider/Clojurescript/browser repl toolchain settles into something stable I would caution anyone trumpeting the advantages of Emacs. For Clojurescript the current state of play seems to favour Lighttable and Cursive. gvim -- 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/d/optout. -- 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/d/optout.
Re: [ANN] async-sockets - work with sockets using core.async channels
On Sun, Oct 5, 2014 at 11:57 PM, Zach Tellman ztell...@gmail.com wrote: If I'm reading this correctly, you're using non-blocking thread pools for blocking operations on the sockets. Given more than N connections (last time I looked the thread pool's size was 42), you risk deadlock or at the very least poor average throughput. I'd thought the thread pool's size was a function of your core count plus some constant, which I believe is 42. But yes, that is a constraint, and deadlock is a risk with too many concurrent connections. I haven't tried to measure throughput yet but that seems like a reasonable next step. Thanks for the code review! -- 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/d/optout.
Re: [ANN] async-sockets - work with sockets using core.async channels
On Mon, Oct 6, 2014 at 12:10 AM, adrian.med...@mail.yu.edu wrote: Zach makes an excellent point; I've used AsyncSocketChannels and its irk ( http://docs.oracle.com/javase/8/docs/api/java/nio/channels/AsynchronousServerSocketChannel.html), with core.async in the past. Perhaps replacing your direct java.net.Sockets with nio classes that can be given CompletionHandlers ( http://docs.oracle.com/javase/7/docs/api/java/nio/channels/CompletionHandler.html) would be a better fit. Once I do some performance instrumentation I'll give that a shot. I admit that I'm not familiar with all the implications of using the nio classes; were I to switch, is it safe to continue using go blocks, or is it worth explicitly allocating a single thread per socket? Brian -- 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/d/optout.
Re: [ANN] Silk, an isomorphic routing library for Clojure and ClojureScript
Sorry i don't have time to really explain any of this... but here's some code I pulled out of a recent project. maybe it'll be helpful to you. unfortunately I can't share the whole project. https://gist.github.com/pleasetrythisathome/7adbdc9c8b7ab689df45 -- 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/d/optout.
[ANN] Clojure instaREPL for web
A web based clojure instaREPL, Check it out :) http://clojurerepl.com -- 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/d/optout.
Re: [ANN] async-sockets - work with sockets using core.async channels
It's not about 'safety' (depending on what that means in this context), but as Zach pointed out, if you aren't careful about backpressure you can run into performance bottlenecks with unrestrained async IO operations because although they let you code as if you could handle an unlimited amount of connections, obviously that isn't true. There is only a finite amount of data that can be buffered in and out of any network according to its hardware. When you don't regulate that, your system will end up spending an inordinate amount of time compensating for this. You don't need to worry about this with regular io because the thread per connection abstraction effectively bounds your activity within the acceptable physical constraints of the server. On Tuesday, October 7, 2014 2:49:30 PM UTC-4, Brian Guthrie wrote: On Mon, Oct 6, 2014 at 12:10 AM, adrian...@mail.yu.edu javascript: wrote: Zach makes an excellent point; I've used AsyncSocketChannels and its irk ( http://docs.oracle.com/javase/8/docs/api/java/nio/channels/AsynchronousServerSocketChannel.html), with core.async in the past. Perhaps replacing your direct java.net.Sockets with nio classes that can be given CompletionHandlers ( http://docs.oracle.com/javase/7/docs/api/java/nio/channels/CompletionHandler.html) would be a better fit. Once I do some performance instrumentation I'll give that a shot. I admit that I'm not familiar with all the implications of using the nio classes; were I to switch, is it safe to continue using go blocks, or is it worth explicitly allocating a single thread per socket? Brian -- 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/d/optout.
Evaluation order
Hi, I can't figure this out. I have these two functions: (defn get-number [] (try (let [input (read-string (read-line))] (if (number? input) input (get-number))) (catch Exception e (get-number (defn selection-handler [tests] (dotimes [i (count tests)] (printf (%s) %s: %s\n (inc i) (first (nth tests i)) (or (second (nth tests i)) --))) (loop [input (dec (get-number))] (if ((set (range (count tests))) input) (nth tests input) (recur (dec (get-number)) Now, the problem is that when I run selection-handler, the dotimes output isn't printed until (get-number) has returned. Why is this? -- 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/d/optout.
What is the reasoning behind the Transducers eduction function?
There's a few new functions that have been added with Transducers which mostly have very clear use cases to me. What are the use cases for the new eduction http://clojure.github.io/clojure/branch-master/clojure.core-api.html#clojure.core/eduction function? (which looks like it was previously called iteration). The example at http://clojure.org/transducers is informative. It looks similar to sequence in that it produces something that is seq-able with the major difference being that the transform is applied each time the sequence is traversed. You can see the difference here in this code (This uses iteration instead of eduction because I was on 1.7.0-alpha2) (def to-str-iteration (iteration (map (fn [i] (println iteration i) (str i))) (range 3))) (def to-str-seq (sequence (map (fn [i] (println sequence i) (str i))) (range 3))) (println First iteration) (dorun to-str-iteration) (println Second iteration) (dorun to-str-iteration) (println First sequence) (dorun to-str-seq) (println Second sequence) (dorun to-str-seq) Printed: First iteration iteration 0 iteration 0 iteration 1 iteration 2 Second iteration iteration 0 iteration 0 iteration 1 iteration 2 First sequence sequence 0 sequence 1 sequence 2 Second sequence Should we use eduction when we need side effects or reading the current state during a transform and sequence when the transform is pure? Or is there a subtler difference between the two that I'm missing? -- 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/d/optout.
Re: Evaluation order
*output On Tuesday, October 7, 2014 8:17:34 PM UTC-4, adrian...@mail.yu.edu wrote: You need to flush the input stream after printing. Call (clojure.core/flush) to do so. On Tuesday, October 7, 2014 4:51:05 PM UTC-4, Johannes Langøy wrote: Hi, I can't figure this out. I have these two functions: (defn get-number [] (try (let [input (read-string (read-line))] (if (number? input) input (get-number))) (catch Exception e (get-number (defn selection-handler [tests] (dotimes [i (count tests)] (printf (%s) %s: %s\n (inc i) (first (nth tests i)) (or (second (nth tests i)) --))) (loop [input (dec (get-number))] (if ((set (range (count tests))) input) (nth tests input) (recur (dec (get-number)) Now, the problem is that when I run selection-handler, the dotimes output isn't printed until (get-number) has returned. Why is this? -- 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/d/optout.
Re: Evaluation order
You need to flush the input stream after printing. Call (clojure.core/flush) to do so. On Tuesday, October 7, 2014 4:51:05 PM UTC-4, Johannes Langøy wrote: Hi, I can't figure this out. I have these two functions: (defn get-number [] (try (let [input (read-string (read-line))] (if (number? input) input (get-number))) (catch Exception e (get-number (defn selection-handler [tests] (dotimes [i (count tests)] (printf (%s) %s: %s\n (inc i) (first (nth tests i)) (or (second (nth tests i)) --))) (loop [input (dec (get-number))] (if ((set (range (count tests))) input) (nth tests input) (recur (dec (get-number)) Now, the problem is that when I run selection-handler, the dotimes output isn't printed until (get-number) has returned. Why is this? -- 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/d/optout.
Re: [ANN] async-sockets - work with sockets using core.async channels
BTW, is there any network based core.async channel available now? On 10/08/2014 04:36 AM, adrian.med...@mail.yu.edu wrote: It's not about 'safety' (depending on what that means in this context), but as Zach pointed out, if you aren't careful about backpressure you can run into performance bottlenecks with unrestrained async IO operations because although they let you code as if you could handle an unlimited amount of connections, obviously that isn't true. There is only a finite amount of data that can be buffered in and out of any network according to its hardware. When you don't regulate that, your system will end up spending an inordinate amount of time compensating for this. You don't need to worry about this with regular io because the thread per connection abstraction effectively bounds your activity within the acceptable physical constraints of the server. On Tuesday, October 7, 2014 2:49:30 PM UTC-4, Brian Guthrie wrote: On Mon, Oct 6, 2014 at 12:10 AM, adrian...@mail.yu.edu javascript: wrote: Zach makes an excellent point; I've used AsyncSocketChannels and its irk (http://docs.oracle.com/javase/8/docs/api/java/nio/channels/AsynchronousServerSocketChannel.html http://docs.oracle.com/javase/8/docs/api/java/nio/channels/AsynchronousServerSocketChannel.html), with core.async in the past. Perhaps replacing your direct java.net.Sockets with nio classes that can be given CompletionHandlers (http://docs.oracle.com/javase/7/docs/api/java/nio/channels/CompletionHandler.html http://docs.oracle.com/javase/7/docs/api/java/nio/channels/CompletionHandler.html) would be a better fit. Once I do some performance instrumentation I'll give that a shot. I admit that I'm not familiar with all the implications of using the nio classes; were I to switch, is it safe to continue using go blocks, or is it worth explicitly allocating a single thread per socket? Brian -- 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 mailto:clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- 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/d/optout.
Re: What is the reasoning behind the Transducers eduction function?
Hello, eduction does not return a seq, or anything already concrete like that, rather it returns a new reducible, with the interesting property lying in the retention of the xform argument (a transducer). This allows you, for instance, to pass around a collection with all the processing steps but the final rendering of the result (a seq? an aggregate result? a vector ? nil?) = it's up to the user of the educible. Since the educible is an unreduced form of the initial collection, then every time it will be realized into a concrete value, the hidden (behind the xform) collection will be traversed, and the transducer-returned reducing function called. Le mercredi 8 octobre 2014, Jason Gilman jason.gil...@gmail.com a écrit : There's a few new functions that have been added with Transducers which mostly have very clear use cases to me. What are the use cases for the new eduction http://clojure.github.io/clojure/branch-master/clojure.core-api.html#clojure.core/eduction function? (which looks like it was previously called iteration). The example at http://clojure.org/transducers is informative. It looks similar to sequence in that it produces something that is seq-able with the major difference being that the transform is applied each time the sequence is traversed. You can see the difference here in this code (This uses iteration instead of eduction because I was on 1.7.0-alpha2) (def to-str-iteration (iteration (map (fn [i] (println iteration i) (str i))) (range 3))) (def to-str-seq (sequence (map (fn [i] (println sequence i) (str i))) (range 3))) (println First iteration) (dorun to-str-iteration) (println Second iteration) (dorun to-str-iteration) (println First sequence) (dorun to-str-seq) (println Second sequence) (dorun to-str-seq) Printed: First iteration iteration 0 iteration 0 iteration 1 iteration 2 Second iteration iteration 0 iteration 0 iteration 1 iteration 2 First sequence sequence 0 sequence 1 sequence 2 Second sequence Should we use eduction when we need side effects or reading the current state during a transform and sequence when the transform is pure? Or is there a subtler difference between the two that I'm missing? -- 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 javascript:_e(%7B%7D,'cvml','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 javascript:_e(%7B%7D,'cvml','clojure%2bunsubscr...@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 javascript:_e(%7B%7D,'cvml','clojure%2bunsubscr...@googlegroups.com');. For more options, visit https://groups.google.com/d/optout. -- Laurent Petit -- 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/d/optout.
