channel

Go channels and deadlock

由 蓝咒 提交于 2019-11-28 21:30:43
问题 I'm trying to understand the Go language. I tried to create two goroutines that chain the flow between them using two channels: func main() { c1 := make(chan int) c2 := make(chan int) go func() { for i := range c1{ println("G1 got", i) c2 <- i } }() go func() { for i := range c2 { println("G2 got", i) c1 <- i } }() c1 <- 1 time.Sleep(1000000000 * 50) } As expected this code prints: G1 got 1 G2 got 1 G1 got 1 G2 got 1 .... Until the main function exits. But if I send another value to one of

How to broadcast a message from a Phoenix Controller to a Channel?

由 六月ゝ 毕业季﹏ 提交于 2019-11-28 18:41:46
Is there a way to broadcast a message to a channel from outside that channel? Maybe something like Channel.broadcast topic, event, data ? I saw something like this here but the final version of Phoenix.Channel.broadcast/3 (as of today) takes a socket which implies the channel and topic. You can use MyApp.Endpoint.broadcast(topic, event, msg) for that. Check http://hexdocs.pm/phoenix/Phoenix.Endpoint.html 来源： https://stackoverflow.com/questions/33960207/how-to-broadcast-a-message-from-a-phoenix-controller-to-a-channel

Priority in Go select statement workaround

由 。_饼干妹妹 提交于 2019-11-28 17:04:01
问题 I wish to have a go routine listening on two channels, blocked when both channels are drained. However, if both channels contains data, I want one to be drained before the other is handled. In the working example below I wish all out to be drained before exit is handled. I use a select -statement which doesn't have any priority order. How might I get around the problem, making all 10 out-values be handled before the exit? package main import "fmt" func sender(out chan int, exit chan bool){

Socket.io: Namespaces, channels & co

由 旧街凉风 提交于 2019-11-28 16:42:42
I have a Node.js web server that runs a socket server on top, which was created using Socket.io . Basically, this works. What I now want to achieve is that the clients that connect are clustered in groups. So there might be some clients which make up group A and some other clients which make up group B. They shall select to which group they belong by adressing a specific URL, either localhost:3000/A or localhost:3000/B . In Socket.io I now want to send messages to all clients in group A or to all clients in group B or to all clients, without looking at their group. It's basically like having a

WCF Channel and ChannelFactory Caching

由 落爺英雄遲暮 提交于 2019-11-28 16:03:11
问题 So I've decided to up the performance a bit in my WCF application, and attempt to cache Channels and the ChannelFactory. There's two questions I have about all of this that I need to clear up before I get started. 1) Should the ChannelFactory be implemented as a singleton? 2) I'm kind of unsure about how to cache/reuse individual channels. Do you have any examples of how to do this you can share? It's probably important to note that my WCF service is being deployed as a stand alone

Golang channel output order

由 不羁岁月 提交于 2019-11-28 14:23:14
func main() { messages := make(chan string) go func() { messages <- "hello" }() go func() { messages <- "ping" }() msg := <-messages msg2 := <-messages fmt.Println(msg) fmt.Println(msg2) The above code consistently prints "ping" and then "hello" on my terminal. I am confused about the order in which this prints, so I was wondering if I could get some clarification on my thinking. I understand that unbuffered channels are blocking while waiting for both a sender and a receiver. So in the above case, when these 2 go routines are executed, there isn't, in both cases,a receiver yet. So I am

proper way of waiting for a go routine to finish

由 牧云@^-^@ 提交于 2019-11-28 05:26:37
问题 I wish to know what is the proper way of waiting for a go routine to finish before exiting the program. Reading some other answers it seems that a bool chan will do the trick, as in Playground link func do_stuff(done chan bool) { fmt.Println("Doing stuff") done <- true } func main() { fmt.Println("Main") done := make(chan bool) go do_stuff(done) <-done //<-done } I have two questions here: why the <- done works at all? what happens if I uncomment the last line? I have a deadlock error. Is

A channel multiplexer

由 感情迁移 提交于 2019-11-28 04:33:01
问题 Note - newbie in Go. I've written a multiplexer that should merge the outputs of an array of channels into one. Happy with constructive criticism. func Mux(channels []chan big.Int) chan big.Int { // Count down as each channel closes. When hits zero - close ch. n := len(channels) // The channel to output to. ch := make(chan big.Int, n) // Make one go per channel. for _, c := range channels { go func() { // Pump it. for x := range c { ch <- x } // It closed. n -= 1 // Close output if all closed

How to wait until buffered channel (semaphore) is empty?

由 早过忘川 提交于 2019-11-28 04:21:15
问题 I have a slice of integers, which are manipulated concurrently: ints := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} I'm using a buffered channel as semaphore in order to have a an upper bound of concurrently running go routines: sem := make(chan struct{}, 2) for _, i := range ints { // acquire semaphore sem <- struct{}{} // start long running go routine go func(id int, sem chan struct{}) { // do something // release semaphore <- sem }(i, sem) } The code above works pretty well until the last or last

How to embed a YouTube channel into a webpage

由 拟墨画扇 提交于 2019-11-28 04:17:48
Can anyone suggest how I embed a youtube channel into a webpage - I am getting conflicting information from various sites, ideally using the custom player if possible? thanks YouTube supports a fairly easy to use iframe and url interface to embed videos, playlists and all user uploads to your channel : https://developers.google.com/youtube/player_parameters For example this HTML will embed a player loaded with a playlist of all the videos uploaded to your channel. Replace YOURCHANNELNAME with the actual name of your channel: <iframe src="http://www.youtube.com/embed/?listType=user_uploads&list
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