channel | 易学教程

Direct Channel usage vs using a Proxy?

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问题 As the title implies I am trying to get an understanding of why in WCF sometimes people choose to "generate proxies" vs using a ChannelFactory to manually create new channel instances. I have seen examples of each, but haven't really found any explanations of WHY you would go for one vs the other. To be honest I have only ever worked with channels and the ChannelFactory<T> from code I have inherited, ie: IChannelFactory<IDuplexSessionChannel> channelFactory = binding.BuildChannelFactory

What is the Advantage of sync.WaitGroup over Channels?

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问题 I'm working on a concurrent Go library, and I stumbled upon two distinct patterns of synchronization between goroutines whose results are similar: Using Waitgroup var wg sync.WaitGroup func main() { words := []string{ "foo", "bar", "baz" } for _, word := range words { wg.Add(1) go func(word string) { time.Sleep(1 * time.Second) defer wg.Done() fmt.Println(word) }(word) } // do concurrent things here // blocks/waits for waitgroup wg.Wait() } Using Channel func main() { words = []string{ "foo",

WCF ChannelFactory and Channel caching in ASP.NET client application

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I'm building a series of WCF Services that are going to be used by more than one application. Because of that I'm trying to define a common library to access WCF services. Knowing that each service request made by different users should use a different Channel I'm thinking in cache the Channel per-request ( HttpContext.Current.Items ) and cache the ChannelFactory used to create the channel per Application ( HttpApplication.Items ) since I can create more than one channel with the same ChannelFactory . However, I have a question regarding this cache mechanism when it comes to closing the

WCF ChannelFactory and channels - caching, reusing, closing and recovery

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问题 I have the following planned architecture for my WCF client library: using ChannelFactory instead of svcutil generated proxies because I need more control and also I want to keep the client in a separate assembly and avoid regenerating when my WCF service changes need to apply a behavior with a message inspector to my WCF endpoint, so each channel is able to send its own authentication token my client library will be used from a MVC front-end, so I'll have to think about possible threading

Wait for the termination of n goroutines

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I need to start a huge amount of goroutines and wait for their termination. The intuitive way seems to use a channel to wait till all of them are finished : package main type Object struct { //data } func (obj *Object) Update(channel chan int) { //update data channel <- 1 return } func main() { channel := make(chan int, n) list := make([]Object, n, m) for { for _, object := range list { go object.Update(channel) } for i := 0; i < n; i++ { <-channel } //now everything has been updated. start again } } But the problem is that the amount of objects and therefore the amount of goroutines could

RabbitMQ: How to specify the queue to publish to?

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RabbitMQ's Channel#basicConsume method gives us the following arguments: channel.basicConsume(queueName, autoAck, consumerTag, noLocal, exclusive, arguments, callback); Giving us the ability to tell RabbitMQ exactly which queue we want to consume from. But Channel#basicPublish has no such equivalency: channel.basicPublish(exchangeName, routingKey, mandatory, immediateFlag, basicProperties, messageAsBytes); Why can't I specify the queue to publish to here?!? How do I get a Channel publishing to, say, a queue named logging ? Thanks in advance! Basically queues can be binded to an exchange based

Go channel vs Java BlockingQueue

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问题 Are there any differences between a Go channel and a Java BlockingQueue? Both are queues with similar blocking and memory model semantics. Optionally both can have a capacity set. 回答1: I would say the biggest difference is that Go channels have support for the select statement, which allow you to perform exactly one channel operation. An example (altered from the Go language specification): select { case i1 = <-c1: print("received ", i1, " from c1\n") case c2 <- i2: print("sent ", i2, " to c2

all goroutines are asleep - deadlock

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问题 For one of my requirement I have to create N number of worker go routines, which will be monitored by one monitoring routine. monitoring routine has to end when all worker routines completes. My code ending in deadlock, please help. import "fmt" import "sync" import "strconv" func worker(wg *sync.WaitGroup, cs chan string, i int ){ defer wg.Done() cs<-"worker"+strconv.Itoa(i) } func monitorWorker(wg *sync.WaitGroup, cs chan string) { defer wg.Done() for i:= range cs { fmt.Println(i) } } func

How to allocate an array of channels

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How to create an array of channels ? For example: replace the following five lines with an array of channels, with a size of 5: var c0 chan int = make(chan int); var c1 chan int = make(chan int); var c2 chan int = make(chan int); var c3 chan int = make(chan int); var c4 chan int = make(chan int); The statement var chans [5]chan int would allocate an array of size 5, but all the channels would be nil . One way would be to use a slice literal: var chans = []chan int { make(chan int), make(chan int), make(chan int), make(chan int), make(chan int), } If you don't want to repeat yourself, you would

ZeroMQ in javascript client

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问题 Have anyone used ZmqSocket.js successfully? I'd like to know how can it be used to establish a safe channel between the browser and a zeromq server app. Is there other/better options for such use case? 回答1: I've never used ZmqSocket.js, but I can tell you that it's probably not a good idea (yet). This is because zmq still assumes that both peers know the protocol well and will blow up if given invalid data (they are working on fixing that, though). What I do right now is have a simple node.js